Meeting Abstract
The Greek horehound, Ballota acetabulosa (Lamiaceae), is an evergreen shrub native to Southeast Greece, Crete, and West Turkey, which attracts a diverse bee community to their dense patches of inflorescences. Flowers of this plant are bilateral, with filaments and styles located on the adaxial side or top of the flower. Bee different species have morphological adaptations to passively collect pollen from this type of flowers. Flowers also feature a nectar guide, which may serve to signal reward and guide the searching behavior of pollinators. To investigate how removal of the flower’s nectar guide affects bee visitors, we conducted an experiment during two days (11-June and 12-June 2014) in two adjacent plots, one control plot and one experimental plot, on the island of Lesvos, Greece. Bee visitation, handling time per bee, and nectar flow per plant were measured during 30-minute trials that were timed at two-hour intervals on each day. Nine bee species visited our plots; however, honey (Apis mellifera) and leaf cutter bees (Megachile lefebvrei) were the most frequent visitors. The relative frequencies of bees differed among trials. Handling time per bee was similar during all trials, but also displayed high variance, suggesting that individual bees might have learned or that innate differences may exist between species. However, a comparison between the two common bee species on the plot revealed that the removal of the nectar guide significantly increased handling time for honey bees but not for leaf cutter bees. Our results support the hypothesis that nectar guides reduce searching behavior of bee foragers.
