Food or defense? The effect of resin collection on stingless bee foraging
Stingless bees are important pollinators in tropical forests. Yet, we know little about their foraging behavior (e.g., their nutritional requirements, or their floral sources visited for resource collection). Many stingless bees not only depend vitally on pollen and nectar for food but also on resin for defense. However, it is unclear how the large effort devoted to collecting resin as a non-food resource affects stingless bees foraging behavior. Therefore, in this study, we analyzed species-specific differences in foraging patterns (i.e., foraging activity, proportion of collected resources, specialization in plants visited) and resource nutritional composition (i.e., sucrose amount in nectar, amino acids in pollen) of seven different stingless bee species in north-western Ecuador with a particular focus on the role of resin collection. We found that species with a high resin intake tended to be more active than species with a low resin intake. Pollen foragers per minute were similar across species. Sucrose intake per minute differed between some species, but was not affected by increased resin intake. Interestingly, high and low resin collecting species partly differed in the plants visited for pollen collection. Pollen amino acid profiles largely, but not completely overlapped between the two groups. Our findings show that resin intake, as a non-nutritional resource, can affect stingless bee foraging patterns and plant choices, highlighting the need for more research focusing on resin collection and use by stingless bees.