Abstract
Observations of five free foraging colonies of Bombus (Megabombus) ruderatus (Fab.) are reported with respect to brood production and mortality. Emphasis is given to the nutrition of larvae and new adults, and larval ejection. Seasonal trends in the sex, caste, and size of adults are reported. Colony size was relatively large for a temperate Bombus species. Intraspecific variation in colony size was related to the timing of male production.