Foraging behavior of Scaptotrigona bees in forested and open habitats: the importance of semiochemicals and visual cues

Stingless bees provide critical pollination services to tropical plant communities and crops, but the literature suggests that non-forested land uses might constrain their foraging movement. They are more abundant at the forest edge than in pastures and flower visitation halves at 600 m from the forest edge. A potential explanation for this pattern is that environmental and architectural properties of non-forest land uses constrain stingless bee foraging. If scent-trails used for bee recruitment were negatively affected by changes in environmental conditions, total recruitment in pastures would be lower than in forests. To test this, scent-trail laying bees (Scaptotrigona genus) were trained to identical ad-libitum feeders filled with a highly profitable sucrose solution, up to 40 m from the nest, in pastures and forests. Separately, to confirm bee’s response to scent-marks, foraging preference trials were conducted with a control and a labial gland-baited feeder. To test experienced forager’s ability to re-locate a food source in both environments, feeders were presented and removed in 5m increments. Preliminary findings suggest that at short distances from the nest a higher number of experienced foragers were able to re-locate feeders displaced in the forest than in the pasture. However, total recruitment was similar in both land uses. Surprisingly, experienced foragers did not lay scent trails and instead guided naïve foragers to feeders. Even if not used in trails, bees preferred feeders baited with the labial gland extract to the control. Further experiments are planned to clarify some of these findings.