Do chiggers prefer female hosts? A case study of Hirsutiella zachvatkini, supported by intraspecific variation of molecular traits

The family Trombiculidae (Actinotrichida: Parasitengona) comprises ca 3,000 species distributed worldwide, reaching the highest diversity in tropical and subtropical zones. Hirsutiella zachvatkini (Schluger, 1948), whose larvae parasitize small mammals, especially rodents and insectivores, is considered one of the most abundant and most prevalent species in the Western Palearctic. Its identification has been hitherto based on coherence of morphological traits, with relatively few reports on intraspecific variation. Recent studies, supported by identical COI sequences obtained from the mites, revealed host-associated phenotypic plasticity in H. zachvatkini. The current project aims at molecular characteristics of populations of H. zachvatkini distributed along the latitudinal, longitudinal and altitudinal gradients in Poland. A comparison of infestation level between the sexes of European bank vole – the most common host of H. zachvatkini, is being carried out. Unexpectedly, the higher activity displayed by male hosts, compared to females, is not reflected in the number of chiggers they carry; the rate of infestation is greater in females.