An association between the climate and variation of the cuticular hydrocarbon pattern was found for several populations of Rhipicephalus sanguineus ticks. Extreme parameters of climate (absolute minimal and maximal temperatures) correlated positively with six compounds (mainly methylalkanes) detected in cuticular hydrocarbon mixtures. In the light of work conducted on cuticular transpiration in arthropods and biochemical phase changes in cuticle lipids, it is suggested that the adaptation of ticks to potential colonization areas is accomplished by detectable changes in cuticular hydrocarbon relationships. These tick strains can be biochemically determined and their adaptation potential, analyzed.