Newly emerged workers of the stingless bee Scaptotrigona aff. depilis prefer stored pollen to fresh pollen

Abstract

Like in honey bees, the pollen collected and stored by stingless bees usually undergoes a fermentation process characterized by increase in moisture, lactic acid, and proliferation of microorganisms. We tested whether 2-day-old Scaptotrigona aff. depilis workers were more attracted to and consumed fermented pollen from old pollen pots (>7 days) or fresh pollen collected from the corbicula of foragers. In each bioassay, we offered both types of pollen to 40 inexperienced workers of one colony for 24 min, and repeated the procedure in ten different colonies. In all cases, there were more bees feeding on the fermented pollen, which was 2.2 times more consumed than the fresh pollen. Our results suggested that fermented pollen attracted more bees potentially due to innate preference of young bees, higher levels of attractant substances present in fermented pollen, or due to associative learning reminiscent from larvae feeding habits.