There are evidences that air temperature and relative humidity exerts influence on the flight activity of the social stingless bees (Meliponini). Particularly, the relatively large species of Melipona Illiger, 1806 would present variation in daily foraging activity very close to variation in relative humidity. In this study, we argue that the relative humidity is a confounding variable. In this same line of argumentation, it was also examined the role of pollen harvest on daily rhythm of foraging. The robust Melipona scutellaris (Latreille, 1811) was used as a model and the flight activity and pollen harvest along the day were measured in 12 colonies (4 colonies/habitat), in three types of habitats with varying rainfall, within the natural distribution range of this species (tropical rainforest, seasonal tropical forest and transition of tropical forest-savannah). Most of flight activity occurs during morning time in the three habitats. Colony foraging is high in the very early morning when the relative humidity is also high, and often associated with peaks of pollen harvest. Flight activity decreases abruptly during the high temperatures around noon time. The relationship between the flight activity and the relative humidity was highly significant and linear, in contrast to the unimodal and significant relationship with temperature. The relationship between the flight activity and the relative humidity is assumed to be contingent within humid tropical habitats, considering the daily microclimate variation and pollen foraging patterns. In particular, the latter pattern supports the hypothesis of temporal partitioning of pollen sources.
Temporal resource partitioning; pollen foraging; physiological constraint; stingless bees
