Abstract
The known world fauna of aphids (Aphididae) recently reached a total of 5000 species, placed in 510 currently accepted genera and recorded from about 300 plant families. Aphids, known from the Triassic, constitute an atypical group of insects characterized by a complex life cycle, accompanied by a change of host plant, as well as heterogony and polymorphism. They are predominantly a northern temperate group, with remarkably few species in the tropics. Cyclical parthenogenesis is a very successful way of exploiting the short-lived growth flushes of temperate plants, and aphids are thus a very successful group in temperate climates, using seasonal clues to time the alternation of the sexual and parthenogenetic phases of their life cycles. Such life cycles cannot however be readily adapted to tropics so most species in this conditions lose the sexual phase of the life cycle. On the other hand, the question is, if under current global warming conditions may result in a change in the distribution of those species.