Temperature, Size and Egg Production in the Cabbage Butterfly, Pieris Rapae L.

Abstract

Larvae reared at low temperatures produce larger pupae and adults than those reared at high temperatures, and pupal weight is linearly related to lifetime egg production; mean egg production in a group reared at 29-3l°C may be twice that of another reared at 17.5-19°C. The number of eggs visible with a dissecting microscope in the ovaries of young females is not proportional to their lifetime production. Once size is taken into account, there is no additional effect of temperature or larval diet on total egg production. The timing of egg production throughout an adult's life is unaffected by its size or by the conditions in which it was reared. but there are marked differences between Australian and Canadian (Vancouver) individuals. The size of eggs is inversely correlated with both the age and the size of the mother. In any particular set of rearing conditions, males tend to be larger than females, and the sexes show an equal and high degree of variation in size.