A theory about the evolutionary history of Lachnidae and comments on the results of some molecular phylogenetic studies of aphids (Hemiptera: Aphidoidea)

Abstract

Several characters of the Lachnidae are discussed, and it is explained why some of them are not plesiomorphies as previously believed, but apomorphies. This applies e.g. to the absence of host alternation in the extant genera, to the short cauda and to the presence of compound eyes in the nymphs and the apterous adults. Some characters are adaptations to attention by ants or ways of feeding. It is concluded that many characters show that the family is relatively young and probably originally had host alternation of the same kind as Aphididae, which is regarded as the sister group. The results of some molecular phylogenetic studies are discussed.