Temporal variation in homing ability of the neotropical stingless bee Scaptotrigona aff. postica (Hymenoptera: Apidae: Meliponini)

Abstract

Body size is a known predictor of foraging distance in stingless bees (Apidae: Meliponini). However, effects of seasonality on foraging distances, particularly in tropical regions, are poorly understood. Here, we use translocation (‘homing’) experiments, the release of marked individuals at various distances from the nest, to investigate how homing abilities of the Neotropical stingless bee, Scaptotrigona aff. postica differ across the transition between wet and dry seasons (February–August) in a heterogenous tropical landscape in the eastern Brazilian Amazon. We also determined nectar sugar concentrations of unmanipulated returning foragers to assess temporal changes in collected resource quality. Maximum and typical homing distances (i.e. distances where 90% and 50% of released bees are lost) were estimated to be 860 and 392 m, respectively, confirming that while some individuals travel long distances, most workers must remain close to nests during foraging trips. Homing distances and collected nectar sugar concentrations showed inverse temporal patterns, as homing range declined in later months (May to August), whereas nectar sugar concentrations increased over the same period. Thus, shorter homing distances in later ‘dry season’ months probably reflected an increased availability of floral resources compared with earlier months. Together, our findings highlight the limited spatial extent of foraging activities in S. aff. postica workers, and that bee homing distances vary with environmental conditions. These results provide useful information for both stingless bee colony management and conservation in humid tropical regions.