Odor discrimination in two conditioned solitary bees, Osmia lignaria and Megachile rotundata (Apidae: Megachilidae)

The majority of bee species are solitary, but little has been done to explore the learning and discriminatory abilities of solitary bees. We hypothesized that solitary bees from the family Megachilidae can be conditioned to discriminate between two odors. For two days, bees were conditioned using a feeder to associate one odor with a sucrose solution reward (positive scent) and to associate a different odor with water (negative scent). On the third day, bees were given 10 min to choose between a positive-scented feeder and a negative-scented feeder, both containing water. The choices of the conditioned bees were compared to those of an unconditioned control group. Using this methodology, the bees’ ability to learn through conditioning and subsequently to discriminate between certain odors was clearly demonstrated. In the future, conditioning procedures may allow us to determine what environmental stimuli are meaningful to solitary bees. We could then use this information for the enhancement of commercial use and propagation of these bee species.