Adaptations of fleas (Siphonaptera) to parasitism

The paper deals with peculiarities of flea structure determined by their parasitism on mammals and birds. On the basis of the data on diversity of morphological characters, the leading role of structures of the frontal and nototrochanteral complexes in the adaptive evolution of Siphonaptera is substantiated. Peculiarities of the pulicoid, ischnopsylloid, palaeopsylloid, and generalized morphological types are analyzed together with examples of narrow morphological specializations. Distribution of fleas of these morphological types over five groups of hosts differing in the degree of mobility and association with nests and burrows is also analyzed.