Figure 1

Schematic development of (a) wood-dwelling termites, (b) ants, (c) the wood-roach Cryptocercus, and (d) other cockroaches, with special emphasis on wing-occurrence. Shown are simplified diagrams of development, single instars are not shown. In wood-dwelling termites, 'wingless' sexuals are neotenic reproductives that can be either apterous or brachypterous depending on the instar from which they developed (see text). In ants, there generally is a bifurcation of development. At latest at the pupal instar (but often much earlier), individuals are determined to become either workers or winged sexuals, or in few cases wingless sexuals. In 'other cockroaches' wing dimorphism is often a sexual dimorphism. Note, the larvae of ants and termites are not equivalent. In termite terminology, instars without wing buds are called larvae, while those with wing buds are termed nymphs. In all other hemimetabolous insects (including the cockroaches) all instars are called nymphs.