BUMBLE BEES SHOW NO PREFERENCE OR INCREASED LANDING SUCCESS ON FLOWERS WITH A LABELLUM VERSUS WITHOUT

Abstract

Flower morphology and insect pollinator interaction are closely interrelated, and the study of bees specifically is particularly prominent in the investigation of foraging behavior in scientific literature (Harder 1985, Lamb & Wells 1995). In this study, we examined the behavior of the common eastern bumble bee (Bombus impatiens) in foraging on flowers with and without a labellum to test whether bees prefer flowers with labellums, or if the presence of a labellum influences bees’ success in landing on flowers. The purpose of this study was to further explore the relationship between the environment provided by the structure of a flower and bees’ behavior and learning, and perhaps more broadly the evolutionary rationale behind flower and pollinator interaction. Using data from 58 bees, each having participated in foraging trials including flowers with and without a labellum, we found that bumble bees show no preference for flowers with a labellum, nor do they demonstrate greater success landing on flowers with a labellum. These findings somewhat contradict much previous research that propose that flowers’ bright colors, patterns, and structural modifications help attract and engage pollinators and facilitate foraging (Dafni & Giurfa 1999, Leonard & Papaj 2011, Whitney et al. 2009). This could indicate that labellums may not have evolved for the purpose of facilitating greater landing ease for bees, and that factors other than providing a platform for landing may be responsible for attracting them and guiding them to nectar.