Patterns of Offspring Production and Sex Allocation in the Small Carpenter Bee, Ceratina flavipes SMITH (Hymenoptera, Xylocopinae)

Parental investment and sex allocation were studied in the small carpenter bee, Ceratina flavipes, a typical K-selected species which is characterized by giant eggs, low fecundity and prolonged longevity. The brood in the nest burrow was composed of several continuous series of subbrood. The size of each subbrood was regularly reduced according to its order, proceeding toward the entrance. On the other hand, the sex ratio (males/males+females) within each subbrood gradually decreased toward the entrance. Conspicuously small-sized female juveniles were produced during the first part of the oviposition period. Such skimped parental investment seems to result from the mother's manipulation so as to produce replacement female who will feed sibs, if the mother should disappear prior to the mother-juvenile cohabiting phase.