SYSTEMATIC RELATIONSHIPS AND THE EVOLUTION OF SOME LIFE-HISTORY ASPECTS IN THE MITE GENUS ENSLINIELLA VITZTHUM, 1925 (ACARI, WINTERSCHMIDTIIDAE)

A phylogenetic analysis of relationships is carried out for the specie s of the mite genus Ensliniella Vitzthum, 1925, all of which are assoc iated with eumenine vespid wasps of the genus Allodynerus Bluthgen. Ve spacarus Baker and Cunliffe, 1960, Kennethiella Cooreman, 1954 and Mon obiacarus Baker and Cunliffe, 1960 are used as outgroups, following th e results of an analysis of generic relationships in the study group. The genus Ensliniella is revised, two new species are described, and t he previously known species are redescribed. The results suggest that the characteristic of producing a second type of male (small type male ) evolved in the ancestor of Kennethiella, Vespacarus and Ensliniella, probably for adaptive reasons. Its maintenance in the latter two gene ra however, is hypothesized to be the result of phylogenetic inertia, rather than some adaptive function. The feeding behaviour in the ances tor of Kennethiella, Vespacarus and Ensliniella changed from feeding o ff the host, to feeding on the host larva and pupa, while the behaviou r of never leaving the host originated in the Vespacarus-Ensliniella l ineage. Host specificity within Ensliniella and the other genera in th e study group is very high. Individual species of Ensliniella occur on ly on a single host, even if several potential host species are sympat ric. The available data suggest cospeciation as a possible explanation for the host association patterns within Ensliniella, but colonizatio n has to be invoked to explain the pattern of association at the gener ic level.