Foraging activity and pollen diets of subterranean stingless bee colonies in response to general flowering in Sarawak, Malaysia

General flowering is a type of supra-annual mast flowering at community level in Southeast Asia, which occurred in 1996 after a four-year interval in northern Sarawak, Malaysia. To examine foraging responses to general flowering, foraging activity and pollen diets of subterranean stingless bee (Trigona spp.) colonies were compared over 3 periods in 1994 and 1996. Among variables of foraging activity (frequency of forager returns, proportions of nectar and pollen foragers), only the frequency of forager returns was significantly higher in 1996 than in 1994. The proportion of nectar foragers differed significantly among periods within a year. Among variables of pollen diet breadth (pollen type richness, diversity and evenness indices), none differed significantly between years or among periods. Pollen diet similarity between colonies did not differ significantly between years, although it differed among periods