Colony Cycle and Foraging Activity of a Tropical-montane Bumblebee, Bombus rufipes (Hymenoptera, Apidae) in Southeast Asia

Nest architecture and colony composition of an oriental tropicalmontane bumblebee, Bombus rufipes, were first described from Java and Sumatra. These nests were constructed in abandoned underground nests of small mammals and contained 38-48 worker-sized and 1-7 queen-sized bees. This species is a nonpocket maker. Batch composition of the nests suggests that the colonies are maintained without collapsing after producing queens, and that a new nest might be initiated by swarming. The number of batches per nest and that of larvae per batch were smaller than those of temperate species. The nest harbored many and diverse inquiline arthropods. The percentage of foragers in the colony was 46-50%, about a half of which were pollen foragers. Workers started foraging just before sunrise, and were so sensitive to an indication of a shower that they could quickly return to their nest just before abrupt heavy showers. Majoring of pollen foragers was assured by an analysis of pollen loads, and main pollen source was Albizzia, Eurya and Melastoma.