Interspecific cuticular hydrocarbon variations and tentative hybrids of Rhipicephalus sanguineus and R. pusillus ticks (Acari: Ixodidae) in nature

The interspecific variation of Rhipicephalus sanguineus and R. pusillus ticks is studied by means of cuticular hydrocarbon gas chromatography, from specimens collected in nature. Several compounds able the effective separation of « pure » strains of both species, together with tentatively determined hybrid specimens, collected exclusively on foxes. Cuticular hydrocarbon features are compared with morphological observations of the hybrid ticks. Those show a variable morphology with mixed characters of both R. sanguineus and R. pusillus, as size and scutal punctations. Also, chromatographic pattern is intermediate between the typical one of the two species. The possibility of hybridation of the two species in nature is discussed, bearing in mind the ecological and biological requirements of both hosts and parasites.