Effect of ultraviolet and green radiation and temperature on flight activity and foraging of three tropical stingless bees

Abstract

Stingless bees (Apidae, Meliponini) comprise a group of eusocial bees with great potential for use in greenhouse pollination. However, low light and increased temperature in these protected systems can compromise bee performance. This study evaluated the effect of reduced light incidence and intensity in the spectral range of ultraviolet (∼ 345 nm) and green (∼ 540 nm) and increased temperature on bee acclimation and foraging behaviour of three tropical stingless bee species (Melipona quadrifasciata, Frieseomelitta varia, and Scaptotrigona cf. postica) in experimental arenas. For M. quadrifasciata foraging was more frequent in the mild-temperature treatments and was not affected by UV and green light reduction. However, Frieseomelitta varia was more active in treatments with higher light incidence and intensity in the UV and green range. In conditions of mild temperature and high luminosity, there was an increase in foraging activity for this species throughout the days of confinement. Lastly, S. cf. postica had the greatest difficulty acclimating, even under conditions of high light incidence and mild temperature. Taken together, our results show that the environmental conditions evaluated (i.e., reduced UV and green light incidence and increased temperature) differentially affected stingless bee species. These results reinforce the need for specific management strategies when using tropical stingless bees as pollinators for greenhouse crops.