Developmental Constraints in the Evolution of Reproductive Strategies: Telescoping of Generations in Parthenogenetic Aphids

Most animal and plant species first grow and then switch to reproduction. Some continue to grow after breeding is initiated. Parthenogenetic aphids have a different reproductive strategy. They invest in both somatic and gonadal growth during their larval development. A developmental constraint is suggested to favour the simultaneous commitment to the growth of both soma and gonads in larval life and the telescoping of generations as an effective means of maximizing the rate of increase. This constraint also explains why aphids produce their offspring singly rather than in clutches as by so doing they keep their gonads approximately the same size and so maximize the use of the energy assimilated by the soma. Key-words: Aphids, developmental constraints, reproductive strategies, telescoping of generations