Behavioural evolution in the cabbage butterfly (Pieris rapae).

Australian and U.K. Pieris rapae differ markedly in their oviposition behaviour; U.K. females produce a more aggregated egg distribution, and lay their eggs more quickly, than do Australian females. The adaptive reason for this divergence probably lies in the relative costs of increased flight time (more costly in the U.K.) and increased local crowding (more costly in Australia). There is also a strong relationship between juvenile developmental rate (at constant temperature) and oviposition behaviour, but the form of this relationship differed between the two populations. The adaptive reasons for the link between developmental rate and behaviour is not clear. It may be that this link represents the tip of the iceberg; i.e. that physiological, developmental, and behabioral characters all co-vary in ways and for reasons that we do not yet understand.