Insects

12 pages, 3417 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Residual Efficacy of Two Diatomaceous Earths from Greece for the Control of Sitophilus oryzae (L.) (Coleoptera: Curculionidae) and Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) on Wheat and Maize

by Georgia V. Baliota, Christos I. Rumbos and Christos G. Athanassiou

Insects 2024, 15(5), 319; https://doi.org/10.3390/insects15050319 - 30 Apr 2024

Viewed by 835

Abstract

We evaluated the persistence and efficacy of two different, in granulometry and content of diatoms, diatomaceous earth (DE) formulations (i.e., DE5 and DE6), against two major beetle species of stored products, i.e., Sitophilus oryzae (L.) (Coleoptera: Curculionidae) and Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae). [...] Read more.

We evaluated the persistence and efficacy of two different, in granulometry and content of diatoms, diatomaceous earth (DE) formulations (i.e., DE5 and DE6), against two major beetle species of stored products, i.e., Sitophilus oryzae (L.) (Coleoptera: Curculionidae) and Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae). The formulations were applied as powders in soft wheat and maize in two doses of 500 and 1000 mg kg⁻¹ (ppm). Samples of the treated grains were taken on the day of application and every 30 days until completion of the six-month period of storage. Adults of S. oryzae and R. dominica were exposed to the treated grains at 25 °C and 55% relative humidity, and the mortality was measured after 7, 14, and 21 days of exposure. Rhyzopertha dominica survival was not affected by any combination of DE formulation, dose, and commodity. Contrariwise, the DEs caused significant adult mortality of S. oryzae, in most of the cases tested. We observed that DE6 was equally effective in both wheat and maize, and no considerable variations were observed in S. oryzae mortality during the 6-month experimental period. Furthermore, DE6 was more effective against S. oryzae than DE5, a difference that could have potentially contributed to the variations in the diatom granulometry between these two DEs. Thus, a DE treatment of 1000 ppm was shown to provide long-term protection of wheat and maize against S. oryzae, but this is strongly dependent on the DE formulation, commodity, and insect species. Overall, such natural resource-based inert silicaceous deposits could be used with success in stored-product protection with only some minor modifications, such as sieving and drying of the raw deposit. Full article

(This article belongs to the Special Issue Chemical and Non-chemical Control in Stored Product Protection: Modern Methods for Old Problems)

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12 pages, 3405 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

The Optimal Choice of Trap Type for the Recently Spreading Jewel Beetle Pests Lamprodila festiva and Agrilus sinuatus (Coleoptera, Buprestidae)

by Eszter Matula, Gábor Bozsik, József Muskovits, Csenge Ruszák, Laura Jávorszky, Jochem Bonte, Márton Paulin, József Vuts, József Fail, Ágoston Tóth, Ádám Egri, Miklós Tóth and Zoltán Imrei

Insects 2023, 14(12), 961; https://doi.org/10.3390/insects14120961 - 18 Dec 2023

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Abstract

BACKGROUND: Two jewel beetle species native to Europe, the cypress jewel beetle, Lamprodila (Palmar, Ovalisia) festiva L. (Buprestidae, Coleoptera), and the sinuate pear tree borer, Agrilus sinuatus Olivier (Buprestidae, Coleoptera), are key pests of ornamental thuja and junipers and of [...] Read more.

BACKGROUND: Two jewel beetle species native to Europe, the cypress jewel beetle, Lamprodila (Palmar, Ovalisia) festiva L. (Buprestidae, Coleoptera), and the sinuate pear tree borer, Agrilus sinuatus Olivier (Buprestidae, Coleoptera), are key pests of ornamental thuja and junipers and of orchard and ornamental rosaceous trees, respectively. Although chemical control measures are available, due to the beetles’ small size, agility, and cryptic lifestyle at the larval stage, efficient tools for their detection and monitoring are missing. Consequently, by the time emerging jewel beetle adults are noticed, the trees are typically significantly damaged. METHODS: Thus, the aim of this study was to initiate the development of monitoring traps. Transparent, light green, and purple sticky sheets and multifunnel traps were compared in field experiments in Hungary. RESULTS: Light green and transparent sticky traps caught more L. festiva and A. sinuatus jewel beetles than non-sticky multifunnel traps, regardless of the larger size of the colored surface of the funnel traps. CONCLUSIONS: Although light green sticky sheets turned out to be optimal for both species, using transparent sheets can reduce catches of non-target insects. The key to the effectiveness of sticky traps, despite their reduced suitability for quantitative comparisons, may lie in the behavioral responses of the beetles to the optical features of the traps. Full article

(This article belongs to the Collection Biology and Control of the Invasive Wood-Boring Beetles)

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12 pages, 3134 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Disruptive Effects of Two Curcuminoids (Demethoxycurcumin and Bisdemethoxycurcumin) on the Larval Development of Drosophila melanogaster

by Jun-Hyoung Jeon, Seon-Ah Jeong, Doo-Sang Park, Hong-Hyun Park, Sang-Woon Shin and Hyun-Woo Oh

Insects 2023, 14(12), 959; https://doi.org/10.3390/insects14120959 - 18 Dec 2023

Cited by 1 | Viewed by 1718

Abstract

Juvenile hormones (JHs) play a central role in insect development, reproduction, and various physiological functions. Curcuminoids generally exhibit a wide range of biological activities, such as antioxidant, anti-inflammatory, antibacterial, and insecticidal, and they exhibit insect growth inhibitory effects. However, research on insecticidal properties [...] Read more.

Juvenile hormones (JHs) play a central role in insect development, reproduction, and various physiological functions. Curcuminoids generally exhibit a wide range of biological activities, such as antioxidant, anti-inflammatory, antibacterial, and insecticidal, and they exhibit insect growth inhibitory effects. However, research on insecticidal properties of curcuminoids has been limited. Moreover, to the best of our knowledge, studies on JHs of insects and curcuminoids are lacking. Therefore, this study aimed to identify the substances that act as JH disruptors (JHDs) from edible plants. Demethoxycurcumin (DMC) and bisdemethoxycurcumin (BDMC), two curcuminoids from the turmeric plant Curcuma longa L. inhibited the formation of a methoprene-tolerant (Met)–Taiman (Tai) heterodimer complex in Drosophila melanogaster, as shown through in vitro yeast two-hybrid assays. An artificial diet containing 1% (w/v) DMC or BDMC significantly reduced the number of D. melanogaster larvae in a concentration-dependent manner; larval development was disrupted, preventing the progression of larvae to pupal stages, resulting in an absence of adults. Building on the results obtained in this study on curcuminoids, researchers can use our study as a reference to develop eco-friendly pesticides. Full article

(This article belongs to the Section Insect Physiology, Reproduction and Development)

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16 pages, 1161 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceReview

Chitosan as a Control Tool for Insect Pest Management: A Review

by Linda Abenaim and Barbara Conti

Insects 2023, 14(12), 949; https://doi.org/10.3390/insects14120949 - 15 Dec 2023

Cited by 3 | Viewed by 2923

Abstract

Chitosan, a polysaccharide derived from the deacetylation of chitin, is a versatile and eco-friendly biopolymer with several applications. Chitosan is recognized for its biodegradability, biocompatibility, and non-toxicity, beyond its antimicrobial, antioxidant, and antitumoral activities. Thanks to its properties, chitosan is used in many [...] Read more.

Chitosan, a polysaccharide derived from the deacetylation of chitin, is a versatile and eco-friendly biopolymer with several applications. Chitosan is recognized for its biodegradability, biocompatibility, and non-toxicity, beyond its antimicrobial, antioxidant, and antitumoral activities. Thanks to its properties, chitosan is used in many fields including medicine, pharmacy, cosmetics, textile, nutrition, and agriculture. This review focuses on chitosan’s role as a tool in insect pest control, particularly for agriculture, foodstuff, and public health pests. Different formulations, including plain chitosan, chitosan coating, chitosan with nematodes, chitosan’s modifications, and chitosan nanoparticles, are explored. Biological assays using these formulations highlighted the use of chitosan–essential oil nanoparticles as an effective tool for pest control, due to their enhanced mobility and essential oils’ prolonged release over time. Chitosan’s derivatives with alkyl, benzyl, and acyl groups showed good activity against insect pests due to improved solubility and enhanced activity compared to plain chitosan. Thus, the purpose of this review is to provide the reader with updated information concerning the use and potential applications of chitosan formulations as pest control tools. Full article

(This article belongs to the Special Issue New Formulations of Natural Substances against Insect Pests)

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12 pages, 1474 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

The Genomics of Isolated Populations of Gampsocleis glabra (Orthoptera: Tettigoniidae) in Central and Western Europe

by Oliver Hawlitschek, Carsten Bruns, Lara-Sophie Dey, Soňa Nuhlíčková, Rob Felix, Hein van Kleef, Jacqueline Nakel and Martin Husemann

Insects 2023, 14(12), 946; https://doi.org/10.3390/insects14120946 - 14 Dec 2023

Cited by 2 | Viewed by 1451

Abstract

Habitat destruction and fragmentation are among the major current threats to global biodiversity. Fragmentation may also affect species with good dispersal abilities. We study the heath bushcricket Gampsocleis glabra, a specialist of steppe-like habitats across Europe that are highly fragmented, investigating if [...] Read more.

Habitat destruction and fragmentation are among the major current threats to global biodiversity. Fragmentation may also affect species with good dispersal abilities. We study the heath bushcricket Gampsocleis glabra, a specialist of steppe-like habitats across Europe that are highly fragmented, investigating if these isolated populations can be distinguished using population genomics and if there are any traces of admixture or dispersal among them. We try to answer these questions using genome-wide SNP data generated with ddRAD sequencing. We calculated F-statistics and visualized differentiation using STRUCTURE plots. While limited by the difficulty of sampling this threatened species, our results show that all populations except one that was represented by a singleton were clearly distinct, with pairwise F_ST values between 0.010 and 0.181. STRUCTURE indicated limited but visible admixture across most populations and probably also an exchange of individuals between populations of Germany and The Netherlands. We conclude that in G. glabra, a certain amount of gene flow has persisted, at least in the past, also among populations that are isolated today. We also detect a possibly more recent dispersal event between a population in The Netherlands and one in Germany, which may be human aided. We suggest that the conservation of larger populations should be maintained, that efforts should be taken to restore abandoned habitat, that the preservation even of small habitat fragments may be beneficial for the conservation of this species, and that these habitats should be regularly monitored for possible (re-)colonization. Full article

(This article belongs to the Special Issue Comparative Cytogenetics and Molecular Systematics of Insects)

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30 pages, 17908 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

New Species of Paussus, Subgenus Scaphipaussus (Coleoptera: Carabidae: Paussinae), from Southeast Asia Reveal Ambiguities in Species Group Limits and High Species Diversity in the Oriental Region

by Michal Bednařík and Ladislav Bocak

Insects 2023, 14(12), 947; https://doi.org/10.3390/insects14120947 - 14 Dec 2023

Cited by 1 | Viewed by 1740

Abstract

Paussus, commonly known as ant nest beetles, is the most diverse genus of Paussinae (Coleoptera: Carabidae) with a very complex taxonomic history. Biodiversity research in Southeast and South Asia yields new species that can contribute to a better understanding of the morphological [...] Read more.

Paussus, commonly known as ant nest beetles, is the most diverse genus of Paussinae (Coleoptera: Carabidae) with a very complex taxonomic history. Biodiversity research in Southeast and South Asia yields new species that can contribute to a better understanding of the morphological disparity and species-group or subgenus delimitation. Here, we describe nine new species from Southeast Asia and China: Paussus (Scaphipaussus) fencli sp. nov. (China), P. (S.) mawdsleyi sp. nov. (Borneo), P. (S.) bakeri sp. nov. (Philippines), P. (S.) jendeki sp. nov. (Laos), P. (S.) saueri sp. nov. (India), P. (S.) annamensis sp. nov. (Vietnam), P. (S.) phoupanensis sp. nov. (Laos, Vietnam), P. (S.) bilyi sp. nov. (Thailand), and P. (S.) haucki sp. nov. (Thailand). We also bring new data on P. (S.) corporaali Reichensperger, 1927 (Java) and P. (S.) madurensis Wasmann, 1913 (India). Besides formal descriptions, we provide photographs of the habitus in the dorsal and dorsolateral view, antennal club, head crest, and male genitalia if the male is available. Based on the comparison of new and earlier described species, we show that the antennae are highly diverse within the Scaphipaussus. Considering other characters, some species are placed in Scaphipaussus, but they differ from putative relatives in the antennal morphology. The presence of the frontal protuberances and crests is a more reliable character. Additional species show that Scaphipaussus is most diverse in southeastern Asia, especially in Indo-Burma. Concerning its supposed late Miocene origin, the group underwent rapid radiation. The species diversity of Scaphipaussus almost doubled in the last decade, and it is highly probable that further species will be described in the future. Full article

(This article belongs to the Section Insect Systematics, Phylogeny and Evolution)

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49 pages, 2248 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceReview

Movement Ecology of Adult Western Corn Rootworm: Implications for Management

by Thomas W. Sappington and Joseph L. Spencer

Insects 2023, 14(12), 922; https://doi.org/10.3390/insects14120922 - 3 Dec 2023

Cited by 3 | Viewed by 2203

Abstract

Movement of adult western corn rootworm, Diabrotica virgifera virgifera LeConte, is of fundamental importance to this species’ population dynamics, ecology, evolution, and interactions with its environment, including cultivated cornfields. Realistic parameterization of dispersal components of models is needed to predict rates of range [...] Read more.

Movement of adult western corn rootworm, Diabrotica virgifera virgifera LeConte, is of fundamental importance to this species’ population dynamics, ecology, evolution, and interactions with its environment, including cultivated cornfields. Realistic parameterization of dispersal components of models is needed to predict rates of range expansion, development, and spread of resistance to control measures and improve pest and resistance management strategies. However, a coherent understanding of western corn rootworm movement ecology has remained elusive because of conflicting evidence for both short- and long-distance lifetime dispersal, a type of dilemma observed in many species called Reid’s paradox. Attempts to resolve this paradox using population genetic strategies to estimate rates of gene flow over space likewise imply greater dispersal distances than direct observations of short-range movement suggest, a dilemma called Slatkin’s paradox. Based on the wide-array of available evidence, we present a conceptual model of adult western corn rootworm movement ecology under the premise it is a partially migratory species. We propose that rootworm populations consist of two behavioral phenotypes, resident and migrant. Both engage in local, appetitive flights, but only the migrant phenotype also makes non-appetitive migratory flights, resulting in observed patterns of bimodal dispersal distances and resolution of Reid’s and Slatkin’s paradoxes. Full article

(This article belongs to the Special Issue Corn Rootworm: Biology, Ecology, Behavior and Integrated Management)

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19 pages, 4286 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Aerosolized Insecticide Spray Distributions and Relationships to Efficacy against Stored Product Pests

by Daniel Brabec, Srinivas Lanka, James F. Campbell, Frank H. Arthur, Deanna S. Scheff and Kun Yan-Zhu

Insects 2023, 14(12), 914; https://doi.org/10.3390/insects14120914 - 28 Nov 2023

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Abstract

Aerosol insecticides are widely used in stored product insect management programs in food facilities. Previous research has shown spatial variation in aerosol efficacy within facilities, but information on how spatial patterns of aerosol droplet concentration, size distribution, dispersal, and deposition contribute to this [...] Read more.

Aerosol insecticides are widely used in stored product insect management programs in food facilities. Previous research has shown spatial variation in aerosol efficacy within facilities, but information on how spatial patterns of aerosol droplet concentration, size distribution, dispersal, and deposition contribute to this variation in efficacy is limited. This study involved two aerosol application systems: a high-pressure cylinder containing TurboCide Py-75^® with pyriproxyfen IGR (ChemTech Ltd., Des Moines, IA, USA) and a hand-held fogger containing Pyrocide 100^® (MGK, Minneapolis, MN, USA) with Diacon II which contains methoprene IGR (Wellmark, Schaumburg, IL, USA). These systems were used at single or multiple application locations. The spray trials were conducted in a small-scale flour mill, Hall Ross Flour Mill (Kansas State University, Manhattan, KS, USA). The droplet size distributions were monitored at multiple positions within the room using nine aerodynamic particle sizing (APS, TSI Incorp, Shoreview, MN, USA) instruments. The APS data collected over the treatment period were summarized into a mass concentration index (MCI), which ranged from 155 to 2549 mg/m³ for Turbocide and 235–5658 mg/m³ for Pyrocide. A second parameter called the Deposition Index (Dep.Idx) was derived to estimate potential insecticide depositions on the floor and has units of g/m². The Dep.Idx was below 5.3 g/m² for most Turbocide applications, while the Dep.Idx was below 8.4 g/m² for most Pyrocide applications. The MCI and Dep.Idx values varied with APS position and spray application location, with proximity to the aerosol application location and degree of obstruction between the release point and APS position contributing to this variation. We assessed the relationship between aerosol droplet parameters and insect efficacy using Tribolium confusum Jacqueline DuVal, the confused flour beetle. The adults were treated directly, while the larvae were treated two weeks later during the residual test (previously published). For Turbocide, efficacy against adults increased with MCI and Dep.Idx values, but for residual efficacy of the IGR, efficacy was high at all aerosol droplet values, so no relationship was apparent. In contrast, the relationship between Pyrocide deposition and adult insect efficacy was highly variable. But with larval insect efficacy, residual larvae control was directly related to increases in Pyrocide MCI and Dep.Idx. Contour plots of Dep.Idx values were developed, which could be used to predict areas of the mill that are not receiving an adequate application rate, and this could be used to develop more effective application strategies for aerosol insecticides in food facilities. Full article

(This article belongs to the Section Insect Pest and Vector Management)

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28 pages, 332 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Plant Resource Use and Pattern of Usage by the Naturalized Orchid Bee (Euglossa dilemma: Hymenoptera: Apidae) in Florida

by Robert W. Pemberton

Insects 2023, 14(12), 909; https://doi.org/10.3390/insects14120909 - 27 Nov 2023

Cited by 3 | Viewed by 1319

Abstract

The Neotropical orchid bee Euglossa dilemma was found to be naturalized in southern Florida in 2003, and, by 2022, it had colonized the southern half of Florida. Observations of the bee’s collection of plant resources, primarily flowers, were made from 2003 through to [...] Read more.

The Neotropical orchid bee Euglossa dilemma was found to be naturalized in southern Florida in 2003, and, by 2022, it had colonized the southern half of Florida. Observations of the bee’s collection of plant resources, primarily flowers, were made from 2003 through to 2022 to document its plant usage and understand the patterns of its plant usage. The bee utilized 259 plant taxa, 237 species, and 22 horticultural forms, in 156 genera and 56 families in 263 total uses. Of 247 taxa of flowers, 120 were visited primarily for nectar, 46 for both nectar and pollen, 60 for pollen, including 42 buzz-pollinated flowers, 15 for fragrance chemicals for the males, and 5 for resin rewards by females for nesting. Fragrance chemicals were also collected by males from the leaves of 12 plant species. These extensive resource use data allowed the following predictions to be made. (1) The bee’s presence in Florida, distant from its native region of Mexico and Central America and the geographical ranges of other orchid bees, would result the usage of many new taxa of plants. True, half, 74/148 (50%), of the genera and one third, 16/51(31%), of the plant families of the plants with flowers used by the bee were not previously recorded as being utilized by Euglossine bees. (2) Like other naturalized bees, it would use relatively more plants from its native range or congeners of these plants. True, 113/148 (76%) of genera with species bearing collected floral rewards are native or congeners with species native to the bee’s native range. (3) Given the bee’s long tongue, ability to buzz pollen from poricidal anthers, and ability to collect and use specialized rewards, it would disproportionately use plants with protected or highly specialized floral rewards. True, 180/247 (72%) utilized species bear rewards which were protected and unavailable to, or of no interest to, most other flower visitors. Full article

(This article belongs to the Special Issue Pollinator Biodiversity and Ecosystem Services)

20 pages, 5384 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Accumulation of Fungal Pathogens Infecting the Invasive Spotted Lanternfly, Lycorma delicatula

by Ann E. Hajek, Thomas A. Everest and Eric H. Clifton

Insects 2023, 14(12), 912; https://doi.org/10.3390/insects14120912 - 27 Nov 2023

Cited by 2 | Viewed by 1808

Abstract

In the eastern United States, populations of the invasive spotted lanternfly, Lycorma delicatula, are abundant and spreading. Four species of naturally occurring entomopathogenic fungi have previously been reported as infecting these planthoppers, with two of these causing epizootics. Nymphal- and adult-stage lanternflies [...] Read more.

In the eastern United States, populations of the invasive spotted lanternfly, Lycorma delicatula, are abundant and spreading. Four species of naturally occurring entomopathogenic fungi have previously been reported as infecting these planthoppers, with two of these causing epizootics. Nymphal- and adult-stage lanternflies in Pennsylvania and New York were surveyed for entomopathogenic fungal infections from October 2021 to November 2023, and assays were conducted to confirm the pathogenicity of species that were potentially pathogenic. Beauveria bassiana was the most abundant pathogen, but we report an additional 15 previously unreported species of entomopathogenic fungi infecting spotted lanternflies, all in the order Hypocreales (Ascomycota). The next most common pathogens were Fusarium fujikuroi and Sarocladium strictum. While infection prevalence by species was often low, probably impacted to some extent by the summer drought in 2022, together these pathogens caused a total of 6.7% mortality. A significant trend was evident over time within a season, with low levels of infection among nymphs and higher infection levels in mid- and late-stage adults, the stages when mating and oviposition occur. Full article

(This article belongs to the Section Insect Behavior and Pathology)

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16 pages, 13385 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Occurrence and Population Density of the Endemic Species Cordulegaster buchholzi (Anisoptera: Cordulegastridae) on the Cyclades Islands in Greece

by Otakar Holuša and Kateřina Holušová

Insects 2023, 14(11), 896; https://doi.org/10.3390/insects14110896 - 20 Nov 2023

Viewed by 1155

Abstract

Our research was focused on determining the geomorphological characteristics of streams, characteristics of sediment in streams, habitat, emergence sites and flight period. Larvae were recorded in 19 streams (altitude of 35–680 m a.s.l.), with an average minimum width of 44.2 cm, an average [...] Read more.

Our research was focused on determining the geomorphological characteristics of streams, characteristics of sediment in streams, habitat, emergence sites and flight period. Larvae were recorded in 19 streams (altitude of 35–680 m a.s.l.), with an average minimum width of 44.2 cm, an average maximum width of 352.9 cm, an average minimum depth of 9 cm and an average maximum depth (in pools) of 55 cm, with an average stream gradient of 12 grades (range 0.6–45 grades). In terms of grain size, the sediment in these biotopes can be characterized as sandy gravel, medium-grained gravel with an admixture of fine sand and an admixture of coarse-grained gravel prevails (with dominancy of fraction 2–5 mm with a representation of 47%). The larval density reached 0.1–62.2 larvae per 1 m² of suitable sediment. Exuviae (100 exuviae found in total) occurred at an average of 66 cm horizontal distance from the shore and an average vertical height of 124 cm above the ground. The average total distance of larval movement was 190 cm. The emergence site was categorized as larvae-dominated tree trunks (57% of cases), rocks (51%) and overhanging rocks (11%). The flight period was recorded from 17th May to 15th July (literary record—to 15th August) with peak flight activity noted in the third quarter of June. Considering the size of the area—extent of occurrence, the population of C. buchholzi is strongly threatened; according to the IUCN categories it should be classified as endangered (EN). Full article

(This article belongs to the Special Issue A Themed Issue in Honor of Prof. Dr. Xin-Hua Wang on the Occasion of His 70th Birthday: Diversity, Ecology and Evolution of Aquatic Insects)

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11 pages, 4514 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Earwig Releases Provide Accumulative Biological Control of the Woolly Apple Aphid over the Years

by Georgina Alins, Jaume Lordan, Neus Rodríguez-Gasol, Judit Arnó and Ainara Peñalver-Cruz

Insects 2023, 14(11), 890; https://doi.org/10.3390/insects14110890 - 18 Nov 2023

Cited by 2 | Viewed by 1806

Abstract

Nature-based solutions, such as biological control, can strongly contribute to reducing the use of plant protection products. In our study, we assessed the effect of augmentative releases of the European earwig (Forficula auricularia) to control the woolly apple aphid (Eriosoma [...] Read more.

Nature-based solutions, such as biological control, can strongly contribute to reducing the use of plant protection products. In our study, we assessed the effect of augmentative releases of the European earwig (Forficula auricularia) to control the woolly apple aphid (Eriosoma lanigerum), a worldwide pest that causes serious damage to apple trees. The trials were carried out in two organic apple orchards located in Catalonia (NE Spain) from 2017 to 2020. Two treatments were compared: with vs. without earwig release. For the treatment, 30 earwigs per tree were released by means of a corrugated cardboard shelter. These releases were performed once per season and were repeated every year. We periodically assessed the length of the woolly apple aphid colonies, the number of colonies per tree, the percentage of aphids parasitized by Aphelinus mali, and the number of earwigs per shelter. Our results showed that earwig releases reduced the length of the colonies, but this effect was noticeable only for the second year onwards. Moreover, we found that those releases were compatible with A. mali. Overall, we demonstrated the positive impact of earwig releases on the woolly apple aphid control and the importance of considering time on augmentative biological control strategies. Full article

(This article belongs to the Special Issue Biological Control in Temperate Orchards)

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15 pages, 1566 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Complex Effects of a Land-Use Gradient on Pollinators and Natural Enemies: Natural Habitats Mitigate the Effects of Aphid Infestation on Pollination Services

by Tal Shapira, Tohar Roth, Adi Bar, Moshe Coll and Yael Mandelik

Insects 2023, 14(11), 872; https://doi.org/10.3390/insects14110872 - 13 Nov 2023

Viewed by 1595

Abstract

Pollinators and natural enemies are essential ecosystem service providers influenced by land-use and by interactions between them. However, the understanding of the combined impacts of these factors on pollinator and natural enemy activities and their ultimate effects on plant productivity remains limited. We [...] Read more.

Pollinators and natural enemies are essential ecosystem service providers influenced by land-use and by interactions between them. However, the understanding of the combined impacts of these factors on pollinator and natural enemy activities and their ultimate effects on plant productivity remains limited. We investigated the effects of local and landscape vegetation characteristics and the presence of herbivorous pests on pollination and biological control services and their combined influence on phytometer seed set. The study was conducted in a Mediterranean agro-ecosystem, encompassing ten shrubland plots spanning a land-use gradient. Within each plot, we placed caged and uncaged potted phytometer plants that were either aphid-infested or aphid-free. We quantified insect flower visitation, aphid predation and parasitism rates, and fruit and seed set. We found scale-dependent responses of pollinators and natural enemies to land-use characteristics. Flower species richness had a positive impact on aphid parasitism rates but a negative effect on pollinator activity. Notably, we found a more pronounced positive effect of natural areas on pollinator activity in aphid-infested compared to aphid-free plants, indicating a potentially critical role of natural habitats in mitigating the adverse effects of aphid infestation on pollination services. These results highlight the complex and interactive effects of land-use on pollinators and natural enemies, with significant implications for plant productivity. Full article

(This article belongs to the Topic Arthropod Biodiversity: Ecological and Functional Aspects)

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12 pages, 4638 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Identification of a Male-Produced Aggregation Sex Pheromone in Rosalia batesi, an Endemic Japanese Longhorn Beetle

by Midori Fukaya, Satoshi Kiriyama, Saki Yagami, Ryûtarô Iwata, Hiroe Yasui, Masahiko Tokoro, Yunfan Zou and Jocelyn G. Millar

Insects 2023, 14(11), 867; https://doi.org/10.3390/insects14110867 - 10 Nov 2023

Viewed by 1743

Abstract

The longhorned beetle Rosalia batesi Harold (Coleoptera; Cerambycidae) is endemic to Japan, where its range extends from Hokkaido to Kyushu. The colorful adults are well-known to entomologists and collectors worldwide. It is a hardwood-boring species with larvae that develop in dead broad-leaf trees. [...] Read more.

The longhorned beetle Rosalia batesi Harold (Coleoptera; Cerambycidae) is endemic to Japan, where its range extends from Hokkaido to Kyushu. The colorful adults are well-known to entomologists and collectors worldwide. It is a hardwood-boring species with larvae that develop in dead broad-leaf trees. In laboratory bioassays, females were attracted to males, which suggested that males produce a sex pheromone. The congeneric species R. alpina is native to Europe, and another congener, R. funebris, is distributed in North America. The pheromone components produced by males of these species had been previously identified as two compounds from different biosynthetic pathways. In the present study, volatiles were collected from beetles of both sexes, and the analyses of the resulting extracts revealed a single male-specific compound, which was identified as 3,5-dimethyl-6-(1-methylbutyl)-pyran-2-one; this is the same compound as the pheromone of the European R. alpina. This alkylated pyrone structure is, so far, unique among known cerambycid pheromones. In field bioassays with traps baited with the racemic synthetic pheromone, significant numbers of both sexes of R. batesi were attracted in an approximately equal ratio, indicating that the compound is an aggregation-sex pheromone rather than a sex pheromone. Full article

(This article belongs to the Section Insect Physiology, Reproduction and Development)

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11 pages, 1068 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Power Bars: Mormon Crickets Get Immunity Boost from Eating Grasshoppers

by Robert B. Srygley and David H. Branson

Insects 2023, 14(11), 868; https://doi.org/10.3390/insects14110868 - 10 Nov 2023

Cited by 1 | Viewed by 1382

Abstract

In addition to feeding on plants, Mormon crickets Anabrus simplex Haldeman, 1852 predate on invertebrates, including one another, which effectively drives their migration. Carnivory derives from lack of dietary protein, with Mormon crickets deprived of protein having less phenoloxidase (PO) available to combat [...] Read more.

In addition to feeding on plants, Mormon crickets Anabrus simplex Haldeman, 1852 predate on invertebrates, including one another, which effectively drives their migration. Carnivory derives from lack of dietary protein, with Mormon crickets deprived of protein having less phenoloxidase (PO) available to combat foreign invaders, such as fungal pathogens. Because Mormon crickets commonly occur with grasshoppers that feed on the same plants, we investigated interactions between grasshoppers and Mormon crickets, and hypothesized that if Mormon crickets are predatory on grasshoppers, grasshopper abundance would influence the protein available to Mormon crickets and their immunity. In a field setting, we varied densities of Mormon crickets (0, 10, or 20 per cage) and grasshoppers Melanoplus borealis (0, 15, 30, or 45) in 68 1-m² cages. After one month, we measured Mormon cricket dietary preferences and PO activity. As predicted, artificial diet consumption shifted away from protein as grasshopper density increased, and immunocompetence, as measured by PO activity, also increased with grasshopper availability. Although nitrogen availability in the vegetation decreased with increasing insect density, predation became an important source of protein for Mormon crickets that enhanced immunity. Grasshoppers can be an important source of dietary protein for Mormon crickets, with prey availability affecting Mormon cricket immunity to diseases. Full article

(This article belongs to the Section Insect Physiology, Reproduction and Development)

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11 pages, 1303 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Use of Insect Exclusion Row Cover and Reflective Silver Plastic Mulching to Manage Whitefly in Zucchini Production

by Thiago Rutz, Timothy Coolong, Rajagopalbabu Srinivasan, Alton Sparks, Bhabesh Dutta, Clarence Codod, Alvin M. Simmons and Andre Luiz Biscaia Ribeiro da Silva

Insects 2023, 14(11), 863; https://doi.org/10.3390/insects14110863 - 9 Nov 2023

Viewed by 1446

Abstract

The challenges that sweet potato whitefly (Bemisia tabaci) creates for vegetable production have increased in the southeastern U.S. Growers must use intensive insecticide spray programs to suppress extremely high populations during the fall growing season. Thus, the objective of this study [...] Read more.

The challenges that sweet potato whitefly (Bemisia tabaci) creates for vegetable production have increased in the southeastern U.S. Growers must use intensive insecticide spray programs to suppress extremely high populations during the fall growing season. Thus, the objective of this study was to evaluate the use of a reflective plastic mulch and an insect row cover as alternative methods to the current grower practices to manage whiteflies in zucchini (Cucurbita pepo) production. Field experiments were conducted with a two-level factorial experimental design of cover and plastic mulch treatments arranged in a randomized complete block design, with four replications in Georgia in 2020 and 2021, and in Alabama in 2021. Cover treatments consisted of an insect row cover installed on zucchini beds at transplanting and removed at flowering and a no-cover treatment, while plastic mulch treatments consisted of reflective silver plastic mulching and white plastic mulching. During all growing seasons, weather conditions were monitored, whitefly populations were sampled weekly, zucchini biomass accumulation was measured at five stages of crop development, and fruit yield was determined at harvesting. Warm and dry weather conditions early in the growing season resulted in increased whitefly populations, regardless of location and year. In general, the reflective silver plastic mulching reduced whitefly populations compared to the conventional white plastic by 87% in Georgia in 2020, 33% in Georgia in 2021, and 30% in Alabama in 2021. The insect row cover treatment reduced whitefly populations to zero until its removal. Consequently, zucchini plants grown with the insect row cover and reflective silver plastic mulching had an increased rate of biomass accumulation due to the lower insect pressure in all locations. Zucchini grown using silver reflective plastic mulch and row covers had an overall increase of 17% and 14% in total yield compared to white plastic mulch and no-cover treatments, respectively. Significant differences in yield among locations were likely due to severe whitefly pressure early in the fall season, and total yields in Georgia in 2020 (11,451 kg ha⁻¹) were 25% lower than in Georgia in 2021 (15,177 kg ha⁻¹) and in Alabama in 2021 (15,248 kg ha⁻¹). In conclusion, silver plastic mulching and row covers reduced the whitefly population and increased biomass accumulation and total yield. These treatments can be considered ready-to-use integrated pest management practices for growers. Full article

(This article belongs to the Collection Integrated Pest Management Strategies for Horticultural Crops)

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11 pages, 1185 KiB

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Characterization of Olive Fruit Damage Induced by Invasive Halyomorpha halys

by Elissa Daher, Elena Chierici, Stefania Urbani, Nicola Cinosi, Gabriele Rondoni, Maurizio Servili, Franco Famiani and Eric Conti

Insects 2023, 14(11), 848; https://doi.org/10.3390/insects14110848 - 31 Oct 2023

Cited by 3 | Viewed by 1776

Abstract

The brown marmorated stink bug, Halyomorpha halys (Stål), is an invasive species causing economic crop losses. This species was recently detected attacking olive fruits. The aim of this study was to characterize feeding damage. Olive samples were initially collected from a field where [...] Read more.

The brown marmorated stink bug, Halyomorpha halys (Stål), is an invasive species causing economic crop losses. This species was recently detected attacking olive fruits. The aim of this study was to characterize feeding damage. Olive samples were initially collected from a field where H. halys was reported to cause damage to olive fruits. Hence, we conducted a field trial on the Moraiolo variety using sleeve cages to test the effect of H. halys feeding pressure on olive fruit drop and evaluated the effect of feeding on fruit quality. We tested two densities of H. halys (two or eight adults/cage) at two different stages of olive development, pre- and post-pit hardening. High pressure of H. halys before pit hardening caused a significant fruit drop compared to the control. In addition, chemical analysis of damaged and infested fruits revealed higher levels of total phenols compared to healthy fruits. These findings indicate that feeding by H. halys induced a stress response in the plants that could translate in quality variations in the olive drupes. Full article

(This article belongs to the Section Insect Pest and Vector Management)

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15 pages, 1498 KiB

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Contact Efficacy of Two Amorphous Silica Powders against the Red Flour Beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)

by Selladurai Manivannan and Bhadriraju Subramanyam

Insects 2023, 14(11), 833; https://doi.org/10.3390/insects14110833 - 24 Oct 2023

Cited by 4 | Viewed by 1477

Abstract

The contact efficacy of two amorphous silica powders 1 and 2 procured from Imery’s chemicals, Lompoc, CA, USA, were evaluated against the red flour beetle, Tribolium castaneum (Herbst). The efficacy of the silica two powders was evaluated by exposing 10 adults of T. [...] Read more.

The contact efficacy of two amorphous silica powders 1 and 2 procured from Imery’s chemicals, Lompoc, CA, USA, were evaluated against the red flour beetle, Tribolium castaneum (Herbst). The efficacy of the silica two powders was evaluated by exposing 10 adults of T. castaneum to twelve different concentrations of silica powder 1 and 2 for 12, 24, 36, and 48 h. Mortality assessments were made after 14 d, and data on adult progeny production were recorded at 42 d. Complete mortality of T. castaneum was observed when adults were exposed for 36 h to concentrations of 1.5 to 5 g/m² of silica powder 1. Conversely, in tests with silica powder 2, complete mortality was only achieved when adults were exposed for 48 h to concentrations ranging from 0.75 to 5 g/m². Silica powder 1 exhibited greater efficacy in inhibiting adult progeny production in T. castaneum, particularly at a concentration of 2.0 g/m² after 24 h exposure. Overall, silica powder 1 displayed superior performance in terms of adult mortality and the suppression of T. castaneum adult progeny production. This advantage can be attributed to the smaller particle size of silica powder 1 when compared to silica powder 2. Full article

(This article belongs to the Collection Integrated Management and Impact of Stored-Product Pests)

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14 pages, 2380 KiB

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Rapid Evolutionary Adaptation to Diet Composition in the Black Soldier Fly (Hermetia illucens)

by Anton Gligorescu, Long Chen, Kim Jensen, Neda Nasiri Moghadam, Torsten Nygaard Kristensen and Jesper Givskov Sørensen

Insects 2023, 14(10), 821; https://doi.org/10.3390/insects14100821 - 18 Oct 2023

Viewed by 2073

Abstract

Genetic adaptation of Hermetia illucens (BSF) to suboptimal single sourced waste streams can open new perspectives for insect production. Here, four BSF lines were maintained on a single sourced, low-quality wheat bran diet (WB) or on a high-quality chicken feed diet (CF) for [...] Read more.

Genetic adaptation of Hermetia illucens (BSF) to suboptimal single sourced waste streams can open new perspectives for insect production. Here, four BSF lines were maintained on a single sourced, low-quality wheat bran diet (WB) or on a high-quality chicken feed diet (CF) for 13 generations. We continuously evaluated presumed evolutionary responses in several performance traits to rearing on the two diets. Subsequently, we tested responses to interchanged diets, i.e., of larvae that had been reared on low-quality feed and tested on high-quality feed and vice versa to evaluate costs associated with adaptation to different diets. BSF were found to experience rapid adaptation to the diet composition. While performances on the WB diet were always inferior to the CF diet, the adaptive responses were stronger to the former diet. This stronger response was likely due to stronger selection pressure experienced by BSF fed on the low-quality single sourced diet. The interchanged diet experiment found no costs associated with diet adaptation, but revealed cross generational gain associated with the parental CF diet treatment. Our results revealed that BSF can rapidly respond adaptively to diet, although the mechanisms are yet to be determined. This has potential to be utilized in commercial insect breeding to produce lines tailored to specific diets. Full article

(This article belongs to the Section Insect Physiology, Reproduction and Development)

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14 pages, 4503 KiB

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Laboratory Insecticide Efficacy Trials of Lethal Harborages for Control of the Common Bed Bug, Cimex lectularius (Hemiptera: Cimicidae)

by Jutamas Kerdsawang, Kai Dang, Theeraphap Chareonviriyaphap and Stephen L. Doggett

Insects 2023, 14(10), 814; https://doi.org/10.3390/insects14100814 - 14 Oct 2023

Viewed by 5144

Abstract

Over the past two decades, there has been a worldwide resurgence in the bed bugs Cimex lectularius L. and Cimex hemipterus (F.). This is primarily due to insecticide resistance, making bed bug management and eradication challenging and expensive. To address the need for [...] Read more.

Over the past two decades, there has been a worldwide resurgence in the bed bugs Cimex lectularius L. and Cimex hemipterus (F.). This is primarily due to insecticide resistance, making bed bug management and eradication challenging and expensive. To address the need for more affordable control solutions, “lethal harborages” were explored. Cardboard squares were treated using insecticidal dusts at different dosage levels, including silica dioxide, diatomaceous earth, deltamethrin, permethrin, and fipronil. Two strains of C. lectularius, one susceptible and one resistant, were allowed to enter the treated harborages, and mortality rates were recorded daily. The silica dioxide products proved to be the most efficacious, consistently achieving 100% mortality between 14–17 d at the highest dose. An artificial environment trial using the “new ChinChex^®” formulation of silica dioxide resulted in the complete elimination of bed bugs in the treated harborages within 21 d. These findings suggest that lethal harborages, especially those impregnated with silica dioxide, offer a cost-effective solution that could be incorporated into broader integrated bed bug management strategies. This approach may help alleviate the burden of bed bug infestations in economically disadvantaged communities. Full article

(This article belongs to the Section Insect Pest and Vector Management)

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12 pages, 1476 KiB

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The Characterization of Melanaphis sacchari Microbiota and Antibiotic Treatment Effect on Insects

by Beatriz Xoconostle-Cázares, José Abrahán Ramírez-Pool, Leandro Alberto Núñez-Muñoz, Berenice Calderón-Pérez, Brenda Yazmín Vargas-Hernández, Rafael Bujanos-Muñiz and Roberto Ruiz-Medrano

Insects 2023, 14(10), 807; https://doi.org/10.3390/insects14100807 - 11 Oct 2023

Cited by 2 | Viewed by 1475

Abstract

Insects are under constant selective pressure, which has resulted in adaptations to novel niches such as crops. This is the case of the pest Melanaphis sacchari, the sugarcane aphid, native to Africa and currently spreading worldwide. The aphid undergoes successful parthenogenesis, causing [...] Read more.

Insects are under constant selective pressure, which has resulted in adaptations to novel niches such as crops. This is the case of the pest Melanaphis sacchari, the sugarcane aphid, native to Africa and currently spreading worldwide. The aphid undergoes successful parthenogenesis, causing important damage to a variety of crops and leading to important economic losses for farmers. A natural M. sacchari population grown in sorghum was studied to identify its microbiome through the sequencing of its 16S rDNA metagenome. A high proportion of Proteobacteria, followed by Firmicutes, Bacteroidetes, and Actinobacteria, was observed. We also detected Wolbachia, which correlates with the asexual reproduction of its host. M. sacchari was challenged in a bioassay with the antibiotics oxytetracycline and streptomycin, resulting in a dose-dependent decay of its survival rate. The possibility of controlling this pest by altering its microbiota is proposed. Full article

(This article belongs to the Special Issue Biology and Molecular Mechanisms of Plant-Aphid Interactions)

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10 pages, 2835 KiB

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Early Season Monitoring of Tarnished Plant Bug, Lygus lineolaris, in Wild Hosts Using Pheromone Traps

by Justin George, James P. Glover, Gadi V. P. Reddy, Chris Johnson and David R. Hall

Insects 2023, 14(10), 805; https://doi.org/10.3390/insects14100805 - 7 Oct 2023

Cited by 1 | Viewed by 1798

Abstract

The tarnished plant bug, Lygus lineolaris (Hemiptera: Miridae), has a wide host range of over 700 plant species, including 130 crops of economic importance. During early spring, managing the field edges with weeds and other wild hosts is important in preventing early-season infestations [...] Read more.

The tarnished plant bug, Lygus lineolaris (Hemiptera: Miridae), has a wide host range of over 700 plant species, including 130 crops of economic importance. During early spring, managing the field edges with weeds and other wild hosts is important in preventing early-season infestations of L. lineolaris in cotton to prevent damage to the squares and other fruiting structures. Scouting fields for L. lineolaris is time- and labor-intensive, and end-user variability associated with field sampling can lead to inaccuracies. Insect traps that combine visual cues and pheromones are more accurate, sustainable, and economically feasible in contrast to traditional insect detection methods. In this study, we investigated the application of red or white sticky cards baited with the female-produced sex pheromone to monitor overwintering L. lineolaris populations in early spring. Field experiments demonstrated that the red sticky cards baited with a pheromone blend containing hexyl butyrate, (E)-2-hexenyl butyrate, and (E)-4-oxo-2-hexenal in 4:10:7 ratio are highly effective in trapping L. lineolaris adults in early spring before the row crops are planted, and in monitoring their movement into a cotton crop. The monitoring of L. lineolaris should help growers to make judicious decisions on insecticide applications to control early pest infestations, thereby reducing economic damage to cotton. Full article

(This article belongs to the Special Issue Research in Chemical Ecology of Insects of Significance to Forestry and Agriculture)

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11 pages, 788 KiB

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Prediction of the Overseas Migration of the Fall Armyworm, Spodoptera frugiperda, to Japan

by Akira Otuka

Insects 2023, 14(10), 804; https://doi.org/10.3390/insects14100804 - 6 Oct 2023

Cited by 2 | Viewed by 1443

Abstract

(1) Background: The fall armyworm, Spodoptera frugiperda, is an invasive migratory insect pest that first arrived in Japan in early July 2019. Since then, the species has immigrated to Japan mainly in the summer monsoon season and inflicted damage mainly on the [...] Read more.

(1) Background: The fall armyworm, Spodoptera frugiperda, is an invasive migratory insect pest that first arrived in Japan in early July 2019. Since then, the species has immigrated to Japan mainly in the summer monsoon season and inflicted damage mainly on the maize used as animal feed in the western region, where major immigrations occur. In this study, to know the precise arrival timing and area of S. frugiperda for purposes of pest management, a prediction method for its overseas migration from neighboring source areas was developed. (2) Methods: The method uses the Weather Research and Forecast model to give numerical weather predictions and the GEARN-insect model to predict migration. Emigration source areas on the Chinese mainland and the island of Taiwan and the insect’s take-off and flight behaviors were input to the GEARN-insect model to calculate the daily migration prediction figures. (3) Results: In a prediction evaluation using 2-year six-point trapping data in Japan, the prediction method achieved an average hitting ratio of 78%. (4) Conclusions: The method has sufficient prediction quality for operational use. The technique may be applicable to other migratory moths immigrating to Japan, such as the oriental armyworm, Mythimna separata. Full article

(This article belongs to the Section Insect Pest and Vector Management)

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25 pages, 418 KiB

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Biosecurity and Management Strategies for Economically Important Exotic Tephritid Fruit Fly Species in Australia

by Jessica L. Hoskins, Polychronis Rempoulakis, Mark M. Stevens and Bernard C. Dominiak

Insects 2023, 14(10), 801; https://doi.org/10.3390/insects14100801 - 4 Oct 2023

Cited by 2 | Viewed by 2053

Abstract

Exotic tephritid incursions are of high concern to Australia’s biosecurity and its horticultural industries. It is vital that Australia remains ready to respond to incursions as they arise, as an incursion of tephritid fruit fly species will result in significant economic losses. In [...] Read more.

Exotic tephritid incursions are of high concern to Australia’s biosecurity and its horticultural industries. It is vital that Australia remains ready to respond to incursions as they arise, as an incursion of tephritid fruit fly species will result in significant economic losses. In this review, we compared Australian incursion management strategies for fruit flies with global management strategies and identified possible areas where improvements could be made in an Australian context. Overall, Australia has a good understanding of the main tephritid threats, of which Bactrocera species from across the Torres Strait (northern Australia) are of most concern. Effective tools for tephritid detection and early warning surveillance at points of entry are in place at ports and in horticultural areas Australia-wide and provide the basis for initiating biosecurity responses in the event of an incursion. Area-wide control measures used in successful eradication attempts globally are available for use in Australia. However, a specific tephritid emergency response plan identifying suitable response measures and control options for species of concern is not yet available. We have identified that Australia has the policies and management tools available to respond to an exotic tephritid incursion, but the speed at which this could be accomplished would be greatly improved by the development of species-specific emergency response plans. Full article

(This article belongs to the Section Insect Pest and Vector Management)

17 pages, 6083 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Effects of Natural Habitat and Season on Cursorial Spider Assemblages in Mediterranean Vineyards

by Zeana Ganem, Marco Ferrante, Yael Lubin, Igor Armiach Steinpress, Moshe Gish, Rakefet Sharon, Ally R. Harari, Tamar Keasar and Efrat Gavish-Regev

Insects 2023, 14(10), 782; https://doi.org/10.3390/insects14100782 - 25 Sep 2023

Viewed by 1498

Abstract

Natural habitats adjacent to vineyards are presumed to have a positive effect on the diversity of natural enemies within the vineyards. However, these habitats differ in vegetation structure and seasonal phenology and in turn could affect the species composition of natural enemies. Here, [...] Read more.

Natural habitats adjacent to vineyards are presumed to have a positive effect on the diversity of natural enemies within the vineyards. However, these habitats differ in vegetation structure and seasonal phenology and in turn could affect the species composition of natural enemies. Here, we compared the species richness and diversity and the composition of spider assemblages in several locations within three commercial vineyards and the nearby natural habitats in a Mediterranean landscape in northern Israel. We sampled spiders by means of pitfall traps in early and in late summer. Both the time in the season and the habitat (natural versus vineyard) affected spider species richness and diversity. More species were found in early summer (47) than in late summer (33), and more occurred in the natural habitat (34 species) than in the vineyards (27–31 species). Fifteen species were found exclusively in the natural habitat, and only 11 species were shared by the vineyards and natural habitat, four of which were the most abundant and geographically widely distributed species in the samples. In late summer, spider diversity in the natural habitat was higher than within the vineyards: the spider assemblages in the vineyards became dominated by a few species late in the crop season, while those of the natural habitat remained stable. Overall, the natural habitat differed in assemblage composition from all within-vineyard locations, while the three locations within the vineyard did not differ significantly in assemblage composition. Season (early vs. late summer), however, significantly affected the spider assemblage composition. This study documents the large diversity of spiders in a local Mediterranean vineyard agroecosystem. Over 60% of the known spider families in the region occurred in our samples, highlighting the importance of this agroecosystem for spider diversity and the potential for conservation biocontrol, where natural habitats may be a source of natural enemies for nearby vineyards. Full article

(This article belongs to the Section Insect Ecology, Diversity and Conservation)

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21 pages, 5990 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Diversified Rice Farms with Vegetable Plots and Flower Strips Are Associated with Fewer Pesticide Applications in the Philippines

by Finbarr G. Horgan, Enrique A. Mundaca, Buyung A. R. Hadi and Eduardo Crisol-Martínez

Insects 2023, 14(10), 778; https://doi.org/10.3390/insects14100778 - 22 Sep 2023

Cited by 1 | Viewed by 3086

Abstract

Ecological engineering is defined as the design of sustainable ecosystems for the benefit of both human society and the environment. In Southeast Asia, researchers have applied ecological engineering by diversifying farms using flower strips to restore regulatory services to rice ecosystems and thereby [...] Read more.

Ecological engineering is defined as the design of sustainable ecosystems for the benefit of both human society and the environment. In Southeast Asia, researchers have applied ecological engineering by diversifying farms using flower strips to restore regulatory services to rice ecosystems and thereby reduce herbivore-related yield losses and overall pesticide use. We conducted a survey of 302 rice farmers across four regions of the Philippines to assess their farm diversification practices and determine possible associations with pesticide use. Rice was the main product on all farms; however, the farmers also produced fruits and vegetables, either rotated with rice (47% of the farmers) or in small plots in adjacent farmland. In addition, 64% of the farmers produced flowers, herbs, and/or vegetables on rice bunds. Vegetables were cultivated mainly to supplement household food or incomes, but 30% of the farmers also believed that the vegetables reduced pest and weed damage to their rice. We found that 16% of the farmers grew flowers on their bunds to reduce pest damage to rice and vegetables, and many farmers applied botanical extracts, growth stimulants, and insect traps to reduce damage to the vegetables. Some farmers avoided insecticides on rice by using Trichogramma cards. Planting flowers on rice bunds, rearing ducks in the rice fields, and farmers’ recognition of beneficial rice arthropods were statistically significantly associated with lower pesticide (particularly, insecticide) applications to rice. Our results indicate that farm diversification to produce supplementary foods for rural households and access to alternative pest management options can reduce pesticide use on rice farms in tropical Asia. Full article

(This article belongs to the Special Issue Sustainable Management of Arthropod Pests in Agroecosystems)

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14 pages, 2957 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Phylogeny of Rhynchium and Its Related Genera (Hymenoptera: Eumeninae) Based on Universal Single-Copy Orthologs and Ultraconserved Elements

by Min Dai, Shu-Lin He, Bin Chen and Ting-Jing Li

Insects 2023, 14(9), 775; https://doi.org/10.3390/insects14090775 - 20 Sep 2023

Viewed by 1923

Abstract

The subfamily Eumeninae is a large group of fierce predatory insects that prey mainly on the larvae of Lepidoptera pests. Because of the highly similar morphologies of the genus Rhynchium and its related genera in the subfamily, including Rhynchium Spinola, Allorhynchium van der [...] Read more.

The subfamily Eumeninae is a large group of fierce predatory insects that prey mainly on the larvae of Lepidoptera pests. Because of the highly similar morphologies of the genus Rhynchium and its related genera in the subfamily, including Rhynchium Spinola, Allorhynchium van der Vecht, Anterhynchium de Saussure, Pararrhynchium de Saussure, it is essential to delineate their relationships. A previous phylogenetic analysis based on mitochondrial genomes suggested the inconsistent relationships of these genera under traditional classification based on morphological characters. In this study, we first used single-copy orthologs [USCO] and ultraconserved elements [UCE] extracted from 10 newly sequenced low-coverage whole genomes to resolve the phylogenetic relationships of the above genera. The newly sequenced genomes are 152.99 Mb to 211.49 Mb in size with high completeness (BUSCO complete: 91.5–95.6%) and G + C content (36.31–38.76%). Based on extracted 5811 USCOs and 2312 UCEs, the phylogenetic relationships of Rhynchium and its related genera were: ((Allorhynchium + Lissodynerus) + (Pararrhynchium + (Anterhynchium + (Dirhynchium + Rhynchium)))), which was consistent with the mitochondrial genome results. The results supported the genus Rhynchium as monophyletic, whereas Anterhynchium was recovered as paraphyletic, with Anterhynchium (Dirhynchium) as a sister to Rhynchium and hence deserving generic status; In addition, in the genus Pararrhynchium, P. septemfasciatus feanus and P. venkataramani were separated, not clustered on a branch, just as P. septemfasciatus feanus was not together with P. striatum based on mitochondrial genomes. Since Lissodynerus septemfasciatus, the type species of the genus Lissodynerus, was transferred to Pararrhynchium, it is considered that the genus Lissodynerus should be restituted as a valid genus, not a synonym of Pararrhynchium. Full article

(This article belongs to the Collection Hymenoptera: Biology, Taxonomy and Integrated Management)

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17 pages, 7566 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Phylogenetic Structure Revealed through Combining DNA Barcodes with Multi-Gene Data for Agrodiaetus Blue Butterflies (Lepidoptera, Lycaenidae)

by Vladimir A. Lukhtanov, Nazar A. Shapoval, Alexander V. Dantchenko and Wolfgang Eckweiler

Insects 2023, 14(9), 769; https://doi.org/10.3390/insects14090769 - 15 Sep 2023

Cited by 4 | Viewed by 1759

Abstract

The need for multi-gene analysis in evolutionary and taxonomic studies is generally accepted. However, the sequencing of multiple genes is not always possible. For various reasons, short mitochondrial DNA barcodes are the only source of molecular information for some species in many genera, [...] Read more.

The need for multi-gene analysis in evolutionary and taxonomic studies is generally accepted. However, the sequencing of multiple genes is not always possible. For various reasons, short mitochondrial DNA barcodes are the only source of molecular information for some species in many genera, although multi-locus data are available for other species of the same genera. In particular, such situation exists in the species-rich butterfly subgenus Polyommatus (Agrodiaetus). Here, we analyzed the partitioning of this subgenus into species groups by using three data sets. The first data set was represented by short mitochondrial DNA barcodes for all analyzed samples. The second and third data sets were represented by a combination of short mitochondrial DNA barcodes for part of the taxa with longer mitochondrial sequences COI + tRNA-Leu + COII (data set 2) and with longer mitochondrial COI + tRNA-Leu + COII and nuclear 5.8S rDNA + ITS2 + 28S rDNA sequences (data set 3) for the remaining species. We showed that the DNA barcoding approach (data set 1) failed to reveal the phylogenetic structure, resulting in numerous polytomies in the tree obtained. Combined analysis of the mitochondrial and nuclear sequences (data sets 2 and 3) revealed the species groups and the position within these species groups, even for the taxa for which only short DNA barcodes were available. Full article

(This article belongs to the Special Issue Systematics, Ecology and Evolution of Lepidoptera)

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14 pages, 1463 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Volatile Organic Compounds from Cassava Plants Confer Resistance to the Whitefly Aleurothrixus aepim (Goeldi, 1886)

by Thyago Fernando Lisboa Ribeiro, Demetrios José de Albuquerque Oliveira, João Gomes da Costa, Miguel Angel Martinez Gutierrez, Eder Jorge de Oliveira, Karlos Antonio Lisboa Ribeiro Junior, Henrique Fonseca Goulart, Alessandro Riffel and Antonio Euzebio Goulart Santana

Insects 2023, 14(9), 762; https://doi.org/10.3390/insects14090762 - 13 Sep 2023

Viewed by 1314

Abstract

Cassava is an essential tuber crop used to produce food, feed, and beverages. Whitefly pests, including Aleurothrixus aepim (Goeldi, 1886) (Hemiptera: Aleyrodidae), significantly affect cassava-based agroecosystems. Plant odours have been described as potential pest management tools, and the cassava clone M Ecuador 72 [...] Read more.

Cassava is an essential tuber crop used to produce food, feed, and beverages. Whitefly pests, including Aleurothrixus aepim (Goeldi, 1886) (Hemiptera: Aleyrodidae), significantly affect cassava-based agroecosystems. Plant odours have been described as potential pest management tools, and the cassava clone M Ecuador 72 has been used by breeders as an essential source of resistance. In this study, we analysed and compared the volatile compounds released by this resistant clone and a susceptible genotype, BRS Jari. Constitutive odours were collected from young plants and analysed using gas chromatography–mass spectrometry combined with chemometric tools. The resistant genotype released numerous compounds with previously described biological activity and substantial amounts of the monoterpene (E)-β-ocimene. Whiteflies showed non-preferential behaviour when exposed to volatiles from the resistant genotype but not the susceptible genotype. Furthermore, pure ocimene caused non-preferential behaviour in whiteflies, indicating a role for this compound in repellence. This report provides an example of the intraspecific variation in odour emissions from cassava plants alongside information on odorants that repel whiteflies; these data can be used to devise whitefly management strategies. A better understanding of the genetic variability in cassava odour constituents and emissions under field conditions may accelerate the development of more resistant cassava varieties. Full article

(This article belongs to the Collection Advancing the Use of Plant Volatile in Biological Control of Insects and Weeds)

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61 pages, 24679 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

The Morphological Diversity of Dragon Lacewing Larvae (Nevrorthidae, Neuroptera) Changed More over Geological Time Scales Than Anticipated

by Laura Mengel, Simon Linhart, Gideon T. Haug, Thomas Weiterschan, Patrick Müller, Christel Hoffeins, Hans-Werner Hoffeins, Viktor Baranov, Carolin Haug and Joachim T. Haug

Insects 2023, 14(9), 749; https://doi.org/10.3390/insects14090749 - 6 Sep 2023

Cited by 4 | Viewed by 1418

Abstract

Nevrorthidae, the group of dragon lacewings, has often been considered a relic group. Today, dragon lacewings show a scattered distribution, with some species occurring in southern Europe, Japan, Australia, and one in China. The idea that this distribution is only a remnant of [...] Read more.

Nevrorthidae, the group of dragon lacewings, has often been considered a relic group. Today, dragon lacewings show a scattered distribution, with some species occurring in southern Europe, Japan, Australia, and one in China. The idea that this distribution is only a remnant of an originally larger distribution is further supported by fossils of the group preserved in ambers from the Baltic region (Eocene, ca. 35–40 MaBP) and Myanmar (Kachin amber, Cretaceous, ca. 100 MaBP). Larvae of the group are slender and elongated and live mostly in water. Yet, larvae are in fact very rare. So far, only slightly more than 30 larval specimens, counting all extant and fossil larvae, have been depicted in the literature. Here, we report numerous additional specimens, including extant larvae, but also fossil ones from Baltic and Kachin amber. Together with the already known ones, this sums up to over 100 specimens. We analysed quantitative aspects of the morphology of these larvae and compared them over time to identify changes in the diversity. Despite the enriched sample size, the data set is still unbalanced, with, for example, newly hatched larvae (several dozen specimens) only known from the Eocene. We expected little change in larval morphology over geological time, as indicated by earlier studies. However, on the contrary, we recognised morphologies present in fossils that are now extinct. This result is similar to those for other groups of lacewings which have a relic distribution today, as these have also suffered a loss in diversity in larval forms. Full article

(This article belongs to the Section Insect Ecology, Diversity and Conservation)

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14 pages, 981 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Integrated Effect of Plastic Mulches and Biorational Insecticides in Managing Tomato Chlorotic Spot Virus (TCSV) and Its Vector Thrips in Tomatoes

by Rafia A. Khan, Dakshina R. Seal, Shouan Zhang, Oscar E. Liburd and James Colee

Insects 2023, 14(9), 740; https://doi.org/10.3390/insects14090740 - 3 Sep 2023

Viewed by 1233

Abstract

In the USA, tomato chlorotic spot virus (TCSV) was first identified in Miami-Dade County of Florida in 2012. This viral disease is transmitted by thrips (Thysanoptera: Thripidae) of different species, imposing a serious threat to the entire tomato production in the state. Both [...] Read more.

In the USA, tomato chlorotic spot virus (TCSV) was first identified in Miami-Dade County of Florida in 2012. This viral disease is transmitted by thrips (Thysanoptera: Thripidae) of different species, imposing a serious threat to the entire tomato production in the state. Both cultural and chemical control techniques could be essential tools to combat this vector-borne disease. In the present two-year-long study, we determined the effect of different types of plastic mulches and biorational insecticides on managing thrips and TCSV. Results from the leaf and flower samples showed a significantly lower adult thrips population in Entrust^®SC treated tomatoes than in other treated and untreated tomatoes in 2018. Silver on black and silver on white reflective plastic mulches significantly reduced the adult thrips population in 2018. In both study years, marketable yield was significantly higher in tomatoes treated with Entrust^®SC and reflective plastic mulches than in other treatments. The incidence of TCSV was significantly reduced in tomatoes treated with Entrust^®SC and reflective plastic mulches than the untreated control in 2018. Marketable yield was negatively correlated with the thrips population, as observed from the Pearson correlation coefficient analysis. This research describes a potentially viable management program for thrips and thrips-transmitted TCSV. Full article

(This article belongs to the Section Insect Pest and Vector Management)

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14 pages, 314 KiB

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Symbiotic Bacteria Regulating Insect–Insect/Fungus/Virus Mutualism

by Siqi Chen, Aiming Zhou and Yijuan Xu

Insects 2023, 14(9), 741; https://doi.org/10.3390/insects14090741 - 3 Sep 2023

Cited by 2 | Viewed by 2843

Abstract

Bacteria associated with insects potentially provide many beneficial services and have been well documented. Mutualism that relates to insects is widespread in ecosystems. However, the interrelation between “symbiotic bacteria” and “mutualism” has rarely been studied. We introduce three systems of mutualism that relate [...] Read more.

Bacteria associated with insects potentially provide many beneficial services and have been well documented. Mutualism that relates to insects is widespread in ecosystems. However, the interrelation between “symbiotic bacteria” and “mutualism” has rarely been studied. We introduce three systems of mutualism that relate to insects (ants and honeydew-producing Hemiptera, fungus-growing insects and fungi, and plant persistent viruses and vector insects) and review the species of symbiotic bacteria in host insects, as well as their functions in host insects and the mechanisms underlying mutualism regulation. A deeper understanding of the molecular mechanisms and role of symbiotic bacteria, based on metagenomics, transcriptomics, proteomics, metabolomics, and microbiology, will be required for describing the entire interaction network. Full article

(This article belongs to the Section Insect Behavior and Pathology)

14 pages, 1705 KiB

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Sequential and Simultaneous Interactions of Plant Allelochemical Flavone, Bt Toxin Vip3A, and Insecticide Emamectin Benzoate in Spodoptera frugiperda

by Kaiyuan Huang, Haibo He, Shan Wang, Min Zhang, Xuewei Chen, Zhongyuan Deng, Xinzhi Ni and Xianchun Li

Insects 2023, 14(9), 736; https://doi.org/10.3390/insects14090736 - 31 Aug 2023

Cited by 2 | Viewed by 1324

Abstract

Target pests of genetically engineered crops producing both defensive allelochemicals and Bacillus thuringiensis (Bt) toxins often sequentially or simultaneously uptake allelochemicals, Bt toxins, and/or insecticides. How the three types of toxins interact to kill pests remains underexplored. Here we investigated the interactions of [...] Read more.

Target pests of genetically engineered crops producing both defensive allelochemicals and Bacillus thuringiensis (Bt) toxins often sequentially or simultaneously uptake allelochemicals, Bt toxins, and/or insecticides. How the three types of toxins interact to kill pests remains underexplored. Here we investigated the interactions of Bt toxin Vip3A, plant allelochemical flavone, and insecticide emamectin benzoate in Spodoptera frugiperda. Simultaneous administration of flavone LC₂₅ + Vip3A LC₂₅, emamectin benzoate LC₂₅ + Vip3A LC₂₅, and flavone LC₁₅ + emamectin benzoate LC₁₅ + Vip3A LC₁₅ but not flavone LC₂₅ + emamectin LC₂₅ yielded a mortality significantly higher than their expected additive mortality (EAM). One-day pre-exposure to one toxin at LC₅ followed by six-day exposure to the same toxin at LC₅ plus another toxin at LC₅₀ showed that the mortality of flavone LC₅ + Vip3A LC₅₀, emamectin benzoate LC₅ + Vip3A LC₅₀, and Vip3A LC₅ + emamectin benzoate LC₅₀ were significantly higher than their EAM, while that of flavone LC₅ + emamectin benzoate LC₅₀ was significantly lower than their EAM. No significant difference existed among the mortalities of Vip3A LC₅ + flavone LC₅₀, emamectin benzoate LC₅ + flavone LC₅₀, and their EAMs. The results suggest that the interactions of the three toxins are largely synergistic (inductive) or additive, depending on their combinations and doses. Full article

(This article belongs to the Special Issue Resistance of Pests to Insecticidal Proteins from Bacillus thuringiensis (Bt))

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17 pages, 4573 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

The Effect of Habitat on Insect Movements: Experimental Evidence from Wild-Caught Butterflies

by Matteo Marcantonio, Raluca Voda, Daniele Da Re, Quentin Igot, Roger L. H. Dennis, Aurélien Vielfaure, Sophie O. Vanwambeke and Caroline M. Nieberding

Insects 2023, 14(9), 737; https://doi.org/10.3390/insects14090737 - 31 Aug 2023

Viewed by 1591

Abstract

There is broad evidence that the main driver of the ongoing biodiversity crisis is land-use change, which reduces and fragments habitats. The consequence of habitat fragmentation on behavioural responses of fitness-related traits in insects have been so far understudied. In herbivorous insects, oviposition-related [...] Read more.

There is broad evidence that the main driver of the ongoing biodiversity crisis is land-use change, which reduces and fragments habitats. The consequence of habitat fragmentation on behavioural responses of fitness-related traits in insects have been so far understudied. In herbivorous insects, oviposition-related behaviours determine access to larval food, and the fate of the next generation. We present a pilot study to assess differences in behaviours related to movement and oviposition in Limenitis camilla butterflies from Wallonia (Belgium), one of the most fragmented regions in Europe. We first quantified variation in functional habitat connectivity across Wallonia and found that fragmented habitats had more abundant, but less evenly distributed host plants of L. camilla. Secondly, we quantified the behaviours of field-caught L. camilla females originating from habitats with contrasted landscape connectivity in an outdoor experimental setting. We found differences in behaviours related to flight investment: butterflies from fragmented woodlands spent more time in departing flight, which we associated with dispersal, than butterflies from homogenous woodlands. Although results from this study should be interpreted with caution given the limited sample size, they provide valuable insights for the advancement of behavioural research that aims to assess the effects of global changes on insects. Full article

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49 pages, 29234 KiB

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Revisiting the Taxonomy of Cylapocoris Carvalho, 1954 (Hemiptera: Miridae: Cylapinae) with Descriptions of Five New Species and Morphology-Based Phylogenetic Analysis of the Genus

by Andrzej Wolski, Adrian Masłowski and Artur Taszakowski

Insects 2023, 14(9), 721; https://doi.org/10.3390/insects14090721 - 22 Aug 2023

Viewed by 1131

Abstract

This paper provides descriptions of five new species of the Neotropical genus Cylapocoris Carvalho, 1954 (C. bimaculatus n. sp., C. brooksi n. sp., C. carvalhoi n. sp., C. scutellatus n. sp., and C. simplexoides n. sp.). Cylapocoris and Cylapocoroides Carvalho, 1989 are [...] Read more.

This paper provides descriptions of five new species of the Neotropical genus Cylapocoris Carvalho, 1954 (C. bimaculatus n. sp., C. brooksi n. sp., C. carvalhoi n. sp., C. scutellatus n. sp., and C. simplexoides n. sp.). Cylapocoris and Cylapocoroides Carvalho, 1989 are redescribed and rediagnosed. Illustrations of male genitalia, scanning electron micrographs of selected structures of certain taxa, and an identification key to species are provided. Female genitalia are described and illustrated for the first time for Cylapocoris in nine out of 19 known species. A cladistic analysis of the genus, based on 62 morphological characters, is presented as a contribution to the understanding of relationships within Cylapocoris and its relationships with other groups of Cylapinae. The analysis comprises 16 ingroup species and 15 outgroup taxa. Both equal and implied weighting parsimony analyses were used in the phylogenetic reconstruction. We confirm the monophyly of Cylapocoris and its sister-group relationship with Cylapocoroides. Additionally, we identify subgroupings within Cylapocoris. Intertribal relationships within Cylapinae are briefly discussed. Full article

(This article belongs to the Special Issue Phylogeny and Morphological Evolution of Hemiptera)

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15 pages, 2809 KiB

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A New Approach for Detecting Sublethal Effects of Neonicotinoids on Bumblebees Using Optical Sensor Technology

by Vasileia Chatzaki, Marta Montoro, Rámi El-Rashid, Annette Bruun Jensen and Antoine Lecocq

Insects 2023, 14(8), 713; https://doi.org/10.3390/insects14080713 - 17 Aug 2023

Cited by 4 | Viewed by 1812

Abstract

Among insects, bees are important pollinators, providing many vital ecosystem services. The recent pollinator decline is threatening both their diversity and abundance. One of the main drivers of this decline is the extensive use of pesticides. Neonicotinoids, one of the most popular groups [...] Read more.

Among insects, bees are important pollinators, providing many vital ecosystem services. The recent pollinator decline is threatening both their diversity and abundance. One of the main drivers of this decline is the extensive use of pesticides. Neonicotinoids, one of the most popular groups of pesticides, can be toxic to bees. In fact, numerous studies have found that neonicotinoids can cause sublethal effects, which can impair the biology, physiology, and colony survival of the bees. Yet, there are still knowledge gaps, and more research is needed to better understand the interaction between neonicotinoids and bees, especially in the field. A new optical sensor, which can automatically identify flying insects using machine learning, has been created to continuously monitor insect activity in the field. This study investigated the potential use of this sensor as a tool for monitoring the sublethal effects of pesticides on bumblebees. Bombus terrestris workers were orally exposed to field-realistic doses of imidacloprid. Two types of exposures were tested: acute and chronic. The flight activity of pesticide-exposed and non-exposed bumblebees was recorded, and the events of the insect flights recorded by the sensor were used in two ways: to extract the values of the wingbeat frequency and to train machine learning models. The results showed that the trained model was able to recognize differences between the events created by pesticide-exposed bumblebees and the control bumblebees. This study demonstrates the possibility of the optical sensor for use as a tool to monitor bees that have been exposed to sublethal doses of pesticides. The optical sensor can provide data that could be helpful in managing and, ideally, mitigating the decline of pollinators from one of their most major threats, pesticides. Full article

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15 pages, 3143 KiB

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Helmet Shape and Phylogeography of the Treehopper Membracis mexicana

by Marisol De-la-Mora and Daniel Pinero

Insects 2023, 14(8), 704; https://doi.org/10.3390/insects14080704 - 14 Aug 2023

Viewed by 1462

Abstract

Membracis mexicana (Hemiptera: Membracidae) is distributed in four biogeographic provinces of Mexico. Field observations indicate that there are different forms of this species, but the distribution of the phenotype and the genetic variation of this species have not been clarified. The aim of [...] Read more.

Membracis mexicana (Hemiptera: Membracidae) is distributed in four biogeographic provinces of Mexico. Field observations indicate that there are different forms of this species, but the distribution of the phenotype and the genetic variation of this species have not been clarified. The aim of this study was to quantify the phenotypic and genetic variation of M. mexicana and determine whether the configuration of biogeographic provinces impacts the distribution of this variation. To achieve this, we analyzed 307 photographs using 19 landmarks and geometric morphometrics to quantify the phenotypic variation in helmets. We sequenced five molecular markers for 205 individuals to describe the phylogeographic pattern. As a result, we identified three morphological configurations of the helmet of M. mexicana and two genetic lineages. The morphotypes are (1) a large and wide helmet with small dorsal spots, (2) a small and narrow helmet with large dorsal spots, and (3) a small and narrow helmet with small spots. Genetic lineages are distributed in southeast and western Mexico. The western lineage corresponds to two helmet morphotypes (1 and 2) and the southeast lineage to morphotype 3. We found that the larger helmets correspond to the western lineage and are distributed in Trans-Mexican Volcanic Belt and Pacific lowlands provinces, whereas the smallest helmets correspond to the southeast lineage and are present in the Veracruzan and Yucatan Peninsula provinces. Full article

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13 pages, 3415 KiB

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Distribution, Vertical Transmission, and Cooperative Mechanisms of Obligate Symbiotic Bacteria in the Leafhopper Maiestas dorsalis (Hemiptera, Cicadellidea)

by Wei Wu, Jia-Ning Lei, Qianzhuo Mao, Yan-Zhen Tian, Hong-Wei Shan and Jian-Ping Chen

Insects 2023, 14(8), 710; https://doi.org/10.3390/insects14080710 - 14 Aug 2023

Cited by 3 | Viewed by 1364

Abstract

Many insects rely on ancient symbiotic bacterial associations for essential nutrition. Auchenorrhyncha commonly harbor two obligate symbionts: Sulcia (Bacteroidetes) and a proteobacterial partner that supplies essential amino acids lacking in their plant-sap diets. In this study focusing on Maiestas dorsalis, we investigated [...] Read more.

Many insects rely on ancient symbiotic bacterial associations for essential nutrition. Auchenorrhyncha commonly harbor two obligate symbionts: Sulcia (Bacteroidetes) and a proteobacterial partner that supplies essential amino acids lacking in their plant-sap diets. In this study focusing on Maiestas dorsalis, we investigated the distribution and vertical transmission of two obligate symbiotic bacteria, Sulcia and Nasuia, within the leafhopper. Sulcia primarily inhabits the external region of the bacteriome, while Nasuia is restricted to the internal region. Both symbionts progressively infiltrate the ovary through the epithelial plug, ultimately reaching the developing primary oocyte. Furthermore, co-phylogenetic analysis suggests a close correlation between the evolution of Auchenorrhyncha insects and the presence of their obligate symbiotic bacteria. Genomic analysis further unveiled the extreme genome reduction of the obligate symbiotic bacteria, with Sulcia retaining genes involved in basic cellular processes and limited energy synthesis, while Nasuia exhibited further gene loss in replication, transcription, translation, and energy synthesis. However, both symbionts retained the genes for synthesizing the essential amino acids required by the host insect. Our study highlights the coevolutionary dynamics between Sulcia, proteobacterial partners, and their insect hosts, shedding light on the intricate nutritional interactions and evolutionary adaptations in Auchenorrhyncha insects. Full article

(This article belongs to the Section Insect Behavior and Pathology)

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14 pages, 2259 KiB

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A Rapid Method for Measuring In Vitro Growth in Entomopathogenic Fungi

by Anna R. Slowik, Helen Hesketh, Steven M. Sait and Henrik H. de Fine Licht

Insects 2023, 14(8), 703; https://doi.org/10.3390/insects14080703 - 13 Aug 2023

Cited by 2 | Viewed by 3391

Abstract

Quantifying the growth of entomopathogenic fungi is crucial for understanding their virulence and pathogenic potential. Traditional methods for determining growth, such as biomass determination or colony growth area, are time-consuming and quantitatively and spatially limited in scope. In this study, we introduce a [...] Read more.

Quantifying the growth of entomopathogenic fungi is crucial for understanding their virulence and pathogenic potential. Traditional methods for determining growth, such as biomass determination or colony growth area, are time-consuming and quantitatively and spatially limited in scope. In this study, we introduce a high-throughput method for rapidly measuring fungal growth using spectrophotometry in small-volume, liquid media cultures in 96-well microplates. Optical density (OD) changes were directly correlated with dry weight of samples for six isolates from three species of the genus Metarhizium to validate spectrophotometric growth measurements, and investigate species- and isolate-specific effects. We quantified fungal biomass from the microcultures by extracting, drying, and weighing mycelial mats. From the relationship established between OD and biomass, we generated standard curves for predicting biomass based on the OD values. The OD measurements clearly distinguished growth patterns among six isolates from three Metarhizium species. The logistic growth phase, as captured by the OD measurements, could be accurately assessed within a span of 80 h. Using isolates of M. acridum, M. brunneum, and M. guizhouense, this technique was demonstrated to be an effective, reproducible, and simple method for rapidly measuring filamentous fungal growth with high precision. This technique offers a valuable tool for studying the growth dynamics of entomopathogenic fungi and investigating the factors that influence their growth. Full article

(This article belongs to the Special Issue Insect–Pathogen Interactions in Mass-Reared Insects)

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18 pages, 2466 KiB

Open AccessFeature PaperMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Anthropogenic Influence on Moth Populations: A Comparative Study in Southern Sweden

by Markus Franzén, Anders Forsman and Bafraw Karimi

Insects 2023, 14(8), 702; https://doi.org/10.3390/insects14080702 - 11 Aug 2023

Cited by 3 | Viewed by 1890

Abstract

As moths are vital components of ecosystems and serve as important bioindicators, understanding the dynamics of their communities and the factors influencing these dynamics, such as anthropogenic impacts, is crucial to understand the ecological processes. Our study focuses on two provinces in southern [...] Read more.

As moths are vital components of ecosystems and serve as important bioindicators, understanding the dynamics of their communities and the factors influencing these dynamics, such as anthropogenic impacts, is crucial to understand the ecological processes. Our study focuses on two provinces in southern Sweden, Västergötland and Småland, where we used province records from 1974 to 2019 in combination with light traps (in 2020) to record the presence and abundance of moth species, subsequently assessing species traits to determine potential associations with their presence in anthropogenically modified landscapes. This study design provides a unique opportunity to assess temporal changes in moth communities and their responses to shifts in environmental conditions, including anthropogenic impacts. Across the Västergötland and Småland provinces in Sweden, we recorded 776 moth taxa belonging to fourteen different taxonomic families of mainly Macroheterocera. We captured 44% and 28% of the total moth species known from these provinces in our traps in Borås (Västergötland) and Kalmar (Småland), respectively. In 2020, the species richness and abundance were higher in Borås than in Kalmar, while the Shannon and Simpson diversity indices revealed a higher species diversity in Kalmar. Between 1974 and 2019, the colonisation rates of the provinces increased faster in Småland. Ninety-three species were found to have colonised these provinces since 1974, showing that species richness increased over the study period. We reveal significant associations between the probability of a species being present in the traps and distinct traits compared to a provincial species pool. Traits over-represented in the traps included species with a high variation in colour patterns, generalist habitat preferences, extended flight periods, lower host plant specificity, and overwintering primarily as eggs. Our findings underscore the ongoing ecological filtering that favours certain species-specific traits. This study sheds light on the roles of climate change and anthropogenic impacts in shaping moth biodiversity, offers key insights into the ecological processes involved, and can guide future conservation efforts. Full article

(This article belongs to the Topic Arthropod Biodiversity: Ecological and Functional Aspects)

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26 pages, 5719 KiB

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A Revision of the Genus Argolis (Hemiptera: Reduviidae: Stenopodainae) from Asia

by Zhuo Chen, Michael D. Webb and Wanzhi Cai

Insects 2023, 14(8), 680; https://doi.org/10.3390/insects14080680 - 31 Jul 2023

Cited by 1 | Viewed by 1708

Abstract

The assassin bug genus Argolis Stål, 1861 (Hemiptera: Reduviidae: Stenopodainae) has a disjunct distribution in Sub-Saharan Africa and Asia. In the present study, the Asian species of Argolis are revised. Two species are recognized, redescribed, and illustrated, with the following new subjective synonyms [...] Read more.

The assassin bug genus Argolis Stål, 1861 (Hemiptera: Reduviidae: Stenopodainae) has a disjunct distribution in Sub-Saharan Africa and Asia. In the present study, the Asian species of Argolis are revised. Two species are recognized, redescribed, and illustrated, with the following new subjective synonyms and new combination proposed: Argolis Stål, 1861 = Bardesanes Distant, 1909, syn. nov. = Neoklugia Distant, 1919, syn. nov.; A. farinator (Reuter, 1882) = N. typica Distant, 1919, syn. nov. = B. sericenotatus Livingstone & Ravichandran, 1989, syn. nov.; A. signata (Distant, 1909), comb. nov. (transferred from Bardesanes) = Caunus noctulus Hsiao, 1977, syn. nov. Lectotypes for C. farinator, B. signatus, and N. typica are designated. A key to separate the two Asian species of Argolis is provided. The sexual dimorphism, systematic relationships, and distribution of Argolis are discussed. Argolis is newly recorded from Laos, Pakistan, and Vietnam. Full article

(This article belongs to the Section Insect Systematics, Phylogeny and Evolution)

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12 pages, 2168 KiB

Open AccessFeature PaperMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Validamycin Inhibits the Synthesis and Metabolism of Trehalose and Chitin in the Oriental Fruit Fly, Bactrocera dorsalis (Hendel)

by Ying Li, Yonghong Xu, Shunjiao Wu, Baohe Wang, Yaying Li, Yinghong Liu and Jia Wang

Insects 2023, 14(8), 671; https://doi.org/10.3390/insects14080671 - 28 Jul 2023

Cited by 3 | Viewed by 1399

Abstract

The oriental fruit fly, Bactrocera dorsalis (Hendel), is a notorious invasive pest that has raised concerns worldwide. Validamycin has been demonstrated to be a very strong inhibitor against trehalase in a variety of organisms. However, whether validamycin can inhibit trehalase activity to suppress [...] Read more.

The oriental fruit fly, Bactrocera dorsalis (Hendel), is a notorious invasive pest that has raised concerns worldwide. Validamycin has been demonstrated to be a very strong inhibitor against trehalase in a variety of organisms. However, whether validamycin can inhibit trehalase activity to suppress trehalose hydrolysis and affect any other relevant physiological pathways in B. dorsalis remains unknown. In this study, the effects of validamycin injection on the synthesis and metabolism of trehalose and chitin were evaluated. The results show that validamycin injection significantly affected trehalase activity and caused trehalose accumulation. In addition, the downstream pathways of trehalose hydrolysis, including the synthesis and metabolism of chitin, were also remarkably affected as the expressions of the key genes in these pathways were significantly regulated and the chitin contents were changed accordingly. Intriguingly, the upstream trehalose synthesis was also affected by validamycin injection due to the variations in the expression levels of key genes, especially BdTPPC1. Moreover, BdTPPC1 was predicted to have a binding affinity to validamycin, and the subsequent in vitro recombinant enzyme activity assay verified the inhibitory effect of validamycin on BdTPPC1 activity for the first time. These findings collectively indicate that validamycin can be considered as a promising potential insecticide for the management of B. dorsalis. Full article

(This article belongs to the Section Insect Physiology, Reproduction and Development)

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11 pages, 2109 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Novel Methodology for Localizing and Studying Insect Dorsal Rim Area Morphology in 2D and 3D

by Vun Wen Jie, Arttu Miettinen and Emily Baird

Insects 2023, 14(8), 670; https://doi.org/10.3390/insects14080670 - 28 Jul 2023

Viewed by 1245

Abstract

Polarized light-based navigation in insects is facilitated by a polarization-sensitive part of the eye, the dorsal rim area (DRA). Existing methods to study the anatomy of the DRA are destructive and time-consuming. We presented a novel method for DRA localization, dissection, and measurement [...] Read more.

Polarized light-based navigation in insects is facilitated by a polarization-sensitive part of the eye, the dorsal rim area (DRA). Existing methods to study the anatomy of the DRA are destructive and time-consuming. We presented a novel method for DRA localization, dissection, and measurement using 3D volumetric images from X-ray micro-computed tomography in combination with 2D photographs. Applying the method on size-polymorphic buff-tailed bumblebees, Bombus terrestris, we found that the DRA was easily obtainable from photographs of the dorsal eye region. Allometric analysis of the DRA in relation to body size in B. terrestris showed that it increased with the body size but not at the same rate. By localizing the DRA of individual bumblebees, we could also perform individual-level descriptions and inter-individual comparisons between the ommatidial structures (lens, crystalline cones, rhabdoms) of three different eye regions (DRA, non-DRA, proximate to DRA). One feature distinct to the bumblebee DRA was the smaller dimension of the crystalline cones in comparison to other regions of the eye. Using our novel methodology, we provide the first individual-level description of DRA ommatidial features and a comparison of how the DRA varies with body size in bumblebees. Full article

(This article belongs to the Collection Insect Sensory Biology)

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14 pages, 2377 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Increased Phenoloxidase Activity Constitutes the Main Defense Strategy of Trichoplusia ni Larvae against Fungal Entomopathogenic Infections

by Kristin R. Duffield, Alayna M. Rosales, Ephantus J. Muturi, Robert W. Behle and José L. Ramirez

Insects 2023, 14(8), 667; https://doi.org/10.3390/insects14080667 - 25 Jul 2023

Cited by 2 | Viewed by 1390

Abstract

The cabbage looper Trichoplusia ni is an important agricultural pest worldwide and is frequently used as a model organism for assessing entomopathogenic fungi virulence, though few studies have measured the host response repertoire to fungal biocontrol agents. Here, we quantified the immune response [...] Read more.

The cabbage looper Trichoplusia ni is an important agricultural pest worldwide and is frequently used as a model organism for assessing entomopathogenic fungi virulence, though few studies have measured the host response repertoire to fungal biocontrol agents. Here, we quantified the immune response of T. ni larvae following exposure to two entomopathogenic fungal species: Beauveria bassiana and Cordyceps javanica. Results from our study demonstrate that T. ni larvae exposed to fungal entomopathogens had higher total phenoloxidase activity compared to controls, indicating that the melanization cascade is one of the main immune components driving defense against fungal infection and contrasting observations from other insect–fungi interaction studies. We also observed differences in host response depending on the species of entomopathogenic fungi, with significantly higher induction observed during infections with B. bassiana than with C. javanica. Larvae exposed to B. bassiana had an increased expression of genes involved in prophenoloxidase response and the Imd, JNK, and Jak/STAT immune signaling pathways. Our results indicate a notable absence of Toll pathway-related responses, further contrasting results to other insect–fungi pathosystems. Important differences were also observed in the induction of antimicrobial effectors, with B. bassiana infections eliciting three antimicrobial effectors (lysozyme, gloverin, and cecropin), while C. javanica only induced cecropin expression. These results provide insight into the host response strategies employed by T. ni for protection against entomopathogenic fungi and increase our understanding of insect–fungal entomopathogen interactions, aiding in the design of more effective microbial control strategies for this important agricultural pest. Full article

(This article belongs to the Section Insect Behavior and Pathology)

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25 pages, 444 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceReview

Overview of Updated Control Tactics for Western Flower Thrips

by Daniel Rodríguez and Ericsson Coy-Barrera

Insects 2023, 14(7), 649; https://doi.org/10.3390/insects14070649 - 20 Jul 2023

Cited by 4 | Viewed by 3032

Abstract

Frankliniella occidentalis Pergande (Thysanoptera: Thripidae), broadly known as Western flower thrips (WFT), are currently one of the most critical pests worldwide in field and greenhouse crops, and their management is full of yet unsolved challenges derived from their high reproductive potential, cryptic habit, [...] Read more.

Frankliniella occidentalis Pergande (Thysanoptera: Thripidae), broadly known as Western flower thrips (WFT), are currently one of the most critical pests worldwide in field and greenhouse crops, and their management is full of yet unsolved challenges derived from their high reproductive potential, cryptic habit, and ability to disperse. The control of this pest relies widely on chemical control, despite the propensity of the species to develop resistance. However, significant advances have been produced through biological and ethological control. Although there has recently been a remarkable amount of new information regarding the management of this pest worldwide, there is no critical analysis of recent developments and advances in the attractive control tactics for WFT, constituting the present compilation’s aim. Hence, this narrative review provides an overview of effective control strategies for managing thrips populations. By understanding the pest’s biology, implementing monitoring techniques, accurately identifying the species, and employing appropriate control measures, farmers and researchers can mitigate the WFT impact on agricultural production and promote sustainable pest management practices. Full article

(This article belongs to the Special Issue Invasive Arthropod Pests - Volume II)

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12 pages, 1837 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

The Effect of X-ray Irradiation on the Fitness and Field Adaptability of the Codling Moth: An Orchard Study in Northeast China

by Jinghan Zhang, Shengwang Huang, Shici Zhao, Xingya Wang, Xianming Yang, Huiyuan Zhao, Ping Gao, Yuting Li and Xueqing Yang

Insects 2023, 14(7), 615; https://doi.org/10.3390/insects14070615 - 7 Jul 2023

Cited by 2 | Viewed by 1337

Abstract

The codling moth, Cydia pomonella (L.), is an invasive agricultural pest of pome fruits and walnuts in China that threatens the apple industry in the Loess Plateau and Bohai Bay; it has developed resistance to many insecticides. Sterile insect technique (SIT) combined with [...] Read more.

The codling moth, Cydia pomonella (L.), is an invasive agricultural pest of pome fruits and walnuts in China that threatens the apple industry in the Loess Plateau and Bohai Bay; it has developed resistance to many insecticides. Sterile insect technique (SIT) combined with area-wide integrated pest management (AW-IPM) can reduce the risk of resistance to insecticides and effectively control some insect pest species. Our previous laboratory experiment found that irradiation with 366 Gy of X-ray caused the males of the codling moth to become sterile. However, the sterility and adaptability of males after being irradiated with 366 Gy X-ray in the field are still unclear. In this study, we investigated the effect of X-ray irradiation on the fitness of male adults that emerged from pupae irradiated with 366 Gy to explore their adaptability and mating competitiveness, and to examine the effect of releasing sterile male insects in orchards in northeast China on the fruit infestation rate of the Nanguo pear. The results showed that 366 Gy of X-ray irradiation significantly reduced the mating competitiveness of males and the hatching rate of the eggs laid by females pairing with sterile males. Meanwhile, the lifespan of the sterile male moths was significantly shorter than that of the normal ones in the field. A pilot test showed that the release twice of sterile male moths in the orchards had no significant effect on the fruit infestation rate. Our field experiments provide a scientific basis for the further optimization of the SIT technology program for controlling C. pomonella. Full article

(This article belongs to the Special Issue Environmentally-Friendly Pest Control Approaches for Invasive Insects)

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12 pages, 1153 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Spent Coffee Grounds and Novaluron Are Toxic to Aedes aegypti (Diptera: Culicidae) Larvae

by Waralee Thanasoponkul, Tanasak Changbunjong, Rattanavadee Sukkurd and Tawee Saiwichai

Insects 2023, 14(6), 564; https://doi.org/10.3390/insects14060564 - 16 Jun 2023

Cited by 2 | Viewed by 2593

Abstract

Aedes aegypti (Diptera: Culicidae) is a vector for mosquito-borne diseases worldwide. Insecticide resistance is a major concern in controlling this mosquito. We investigated the chemical compounds in wet and dry spent coffee grounds (wSCGs and dSCGs) and evaluated the efficacy of dSCGs, wSCGs, [...] Read more.

Aedes aegypti (Diptera: Culicidae) is a vector for mosquito-borne diseases worldwide. Insecticide resistance is a major concern in controlling this mosquito. We investigated the chemical compounds in wet and dry spent coffee grounds (wSCGs and dSCGs) and evaluated the efficacy of dSCGs, wSCGs, and novaluron on the mortality and adult emergence inhibition of Ae. aegypti. We found higher concentrations of chemical compounds in wSCGs than in dSCGs. The wSCGs and dSCGs both contained total phenolic compounds, total flavonoid compounds, caffeic acid, coumaric acid, protocatechuic acid, and vanillic acid. Complete mortality was observed after 48 h of exposure to 50 g/L wSCGs, while similar mortality was found after 120 h of exposure to 10 µg/L of novaluron. The sublethal dose was a concentration of wSCGs (5 g/L) and novaluron (0.01, 0.1, and 1 µg/L) combined that resulted in a larval mortality lower than twenty percent (at 72 h) to determine their synergistic effects. The death rate of larvae exposed in sublethal combination of wSCGs and novaluron was significantly higher than that of its stand-alone. The findings indicate that the combination of wSCGs and novaluron at sublethal concentrations had synergistic effects on the mortality of Ae. aegypti larvae and could be applied as an alternative control measure. Full article

(This article belongs to the Special Issue The Efficacy of Insecticides and Botanicals against Pests)

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18 pages, 4325 KiB

Open AccessFeature PaperMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Northern Richness, Southern Dead End—Origin and Dispersal Events of Pseudolycoriella (Sciaridae, Diptera) between New Zealand’s Main Islands

by Arne Köhler and Thomas Schmitt

Insects 2023, 14(6), 548; https://doi.org/10.3390/insects14060548 - 12 Jun 2023

Viewed by 1459

Abstract

Sciaridae (Diptera) is a widespread insect family of which some species can reach high abundances in arboreal habitats. This trait, together with their (passive) mobility, enables them to quickly colonise suitable habitats. To reveal the biogeographic history of the New Zealand members of [...] Read more.

Sciaridae (Diptera) is a widespread insect family of which some species can reach high abundances in arboreal habitats. This trait, together with their (passive) mobility, enables them to quickly colonise suitable habitats. To reveal the biogeographic history of the New Zealand members of the sciarid genus Pseudolycoriella, we analysed three molecular markers of selected species and populations in a Bayesian approach. At the intra- and interspecific levels, we detected a pattern of northern richness vs. southern purity, which has probably developed as a result of Pleistocene glacial cycles. Since the late Miocene, we identified 13 dispersal events across the sea strait separating New Zealand’s main islands. As nine of these dispersal events were south-directed, North Island can be considered the centre of radiation for this genus. An unequivocal re-colonisation of North Island was only observed once. Based on the inclusion of three undescribed species from Tasmania and on previously published data, three colonisations of New Zealand are likely, all of them assumed to be of Australian origin. One of these most probably took place during the late Miocene, and the other two during the late Pliocene or at the Pliocene–Pleistocene boundary. Full article

(This article belongs to the Special Issue Systematics, Taxonomy and Biodiversity of Sciaridae (Diptera))

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14 pages, 2700 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Granger Causality Analysis of Transient Calcium Dynamics in the Honey Bee Antennal Lobe Network

by Marco Paoli, Yuri Antonacci, Angela Albi, Luca Faes and Albrecht Haase

Insects 2023, 14(6), 539; https://doi.org/10.3390/insects14060539 - 9 Jun 2023

Cited by 2 | Viewed by 1224

Abstract

Odorant processing presents multiple parallels across animal species, and insects became relevant models for the study of olfactory coding because of the tractability of the underlying neural circuits. Within the insect brain, odorants are received by olfactory sensory neurons and processed by the [...] Read more.

Odorant processing presents multiple parallels across animal species, and insects became relevant models for the study of olfactory coding because of the tractability of the underlying neural circuits. Within the insect brain, odorants are received by olfactory sensory neurons and processed by the antennal lobe network. Such a network comprises multiple nodes, named glomeruli, that receive sensory information and are interconnected by local interneurons participating in shaping the neural representation of an odorant. The study of functional connectivity between the nodes of a sensory network in vivo is a challenging task that requires simultaneous recording from multiple nodes at high temporal resolutions. Here, we followed the calcium dynamics of antennal lobe glomeruli and applied Granger causality analysis to assess the functional connectivity among network nodes in the presence and absence of an odorous stimulus. This approach revealed the existence of causal connectivity links between antennal lobe glomeruli in the absence of olfactory stimulation, while at odor arrival, the connectivity network’s density increased and became stimulus-specific. Thus, such an analytical approach may provide a new tool for the investigation of neural network plasticity in vivo. Full article

(This article belongs to the Section Insect Physiology, Reproduction and Development)

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18 pages, 1979 KiB

Open AccessMore Editor’s choice articles in journal Insects.">Editor’s ChoiceArticle

Mosquito Larvicidal Activity and Cytotoxicity of the Extracts of Aromatic Plants from Malaysia

by Huimei Lim, Sook Yee Lee, Lai Yee Ho and Nam Weng Sit

Insects 2023, 14(6), 512; https://doi.org/10.3390/insects14060512 - 1 Jun 2023

Cited by 8 | Viewed by 5511

Abstract

Despite ongoing control efforts, the mosquito population and diseases vectored by them continue to thrive worldwide, causing major health concerns. There has been growing interest in the use of botanicals as alternatives to insecticides due to their widespread insecticidal properties, biodegradability, and adaptability [...] Read more.

Despite ongoing control efforts, the mosquito population and diseases vectored by them continue to thrive worldwide, causing major health concerns. There has been growing interest in the use of botanicals as alternatives to insecticides due to their widespread insecticidal properties, biodegradability, and adaptability to ecological conditions. In this study, we investigated the larvicidal activity and cytotoxicity effects of solvent extracts from three aromatic plants—Curcuma longa (turmeric), Ocimum americanum (hoary basil), and Petroselinum crispum (parsley)—against Aedes albopictus. Subsequently, we examined the phytochemical composition of the extracts through gas chromatography–mass spectrometry (GC–MS) analysis. Results revealed that the hexane extracts of O. americanum and P. crispum exhibited the greatest larvicidal activity with the lowest median lethal concentration (LC₅₀) values (<30 µg/mL) at 24 h post-treatment, with the former found to be significantly less toxic towards African monkey kidney (Vero) cells. The GC–MS analysis of the said extract indicated the presence of different classes of metabolites, including phenylpropanoids, very long-chain alkanes, fatty acids and their derivatives, and terpenes, with the most abundant component being methyl eugenol (55.28%), most of which, have been documented for their larvicidal activities. These findings provide valuable insights into the potential use and development of bioinsecticides, particularly from O. americanum. Full article

(This article belongs to the Special Issue The Efficacy of Insecticides and Botanicals against Pests)

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