[Is parasitism of Metazoa "a one-way ticket"?]

Abstract

Various data considered as possible cases where metazoans return form the obligate parasitism to free mode of life (a violation of ecological interpretation of Dollo's law). It is shown that among temporary and phase parasites their return to the free mode of life is a rare but not exceptional phenomenon. It is possibly to conclude that these cases are displayed only by those ectoparasitic arthropods, ancestors of which were predators. The only, although incompletely proven cases of the violation of Dollo's law among permanent parasites is suggested to be acariform mites of the family Pyroglyphidae (Acariformes: Psoroptoidea).