Bumblebee (Bombus impatiens) visitation behavior to sunflowers (Helianthus annuus) in response to spatial learning and memory of sunflower moth (Homoeosoma electellum) florivory cues

Insects that feed on flowers (florivores) can have significant indirect impacts on the reproductive success of plants that are highly dependent on pollinators for reproduction. Florivores can alter the appearance of flowers, damage flowers, and/or directly compete with pollinators causing them to avoid flowers with florivores present. The goal of this study was to determine to what extent the presence of florivory cues of the sunflower moth (Homoeosoma electellum) on sunflowers (Helianthus annuus) altered bumblebee (Bombus impatiens) visitation behaviors. We set up 5 flowers in a pentagon and recorded the number of bumblebee visits, time spent visiting, and the order in which the bumblebees visited the flowers. Two of the five flowers were then treated with olfactory or visual cues of florivory and the same variables were recorded. After three days, the flowers were replaced with fresh, unmanipulated flowers, and the same variables were recorded again. We found that the number of visits to the flowers was significantly higher for all flowers within the patch during the treatment period (during which some flowers were manipulated), but the length of time the bees spent foraging on the flower was not affected. It is possible that this increase in visitation is a result of increased investigation behaviors to the novel manipulations within the patch. We also found no significant differences in visitation behavior between baseline and reversion periods suggesting that bumblebees rely on current cues present on the flowers rather than spatial memory.