Rhynchophorus palmarum in Disguise: Undescribed Polymorphism in the "Black" Palm Weevil

PLoS One. 2015 Dec 18;10(12):e0143210. doi: 10.1371/journal.pone.0143210. eCollection 2015.

Abstract

During studies to adapt pheromone trapping of Rhynchophorus palmarum to the special coconut growing conditions at the Colombian Pacific coast, 152 atypically-colored specimens were captured in a total collection of 53,802 of the normally completely black weevil. Five specimens had the typical coloration of Rhynchophorus ferrugineus, an invasive species recently introduced to Aruba and Curação. A regional expansion of this invasion to the South American continent was feared and all atypical specimens were submitted to taxonomic analysis. Both conventional and molecular methods were employed. Conventional taxonomics confirmed the samples as belonging to R. palmarum but registered undescribed and species-atypical morphological variability in the subgular suture (wide vs. narrow), the ratio between intraocular distance and width of antennal scrobes (>0.35 vs. < 0.29) and the indentation of the mandibles (up to three mandibular teeth vs. bilobed). Molecular analysis placed all samples inspected, black and reddish alike, firmly within the R. palmarum group and the hypothesis of having inter-specific hybrids was rejected using co-dominant single sequence repeat markers with allelic specificity for both species.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arthropod Antennae / anatomy & histology
  • Eye / anatomy & histology
  • Female
  • Genome, Insect
  • Introduced Species
  • Male
  • Phylogeny
  • Polymorphism, Genetic*
  • Sequence Analysis, DNA / methods
  • Weevils / anatomy & histology*
  • Weevils / classification*
  • Weevils / genetics

Grants and funding

This work was partially funded by Colciencias (www.colciencias.gov.co) grant no. 2236-502-27543 to Centro International de Agricultura Tropical (BL). The remaining costs were covered through CIAT core funds (BL, AAV, LABL). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.