Meeting Abstract
Spiral-horned bees belong to the genus Systropha and are morphologically and biologically interesting organisms. Based on previous data, one can hypothesize a strong association of Systropha with Convolvulaceae because Systropha are thought to be oligolectic on Convolvulaceae flowers, mainly on species of Convolvulus with tricolporate pollen grains. However, despite these morphological divergences in the host plants, the available data suggest an association between Systropha and Convolvulaceae flowers. The comparison between Systropha and Convolvulaceae is studied to understand the circadian rhythm of Systropha. Five 1 x 1 meter patches of Convolvulus were selected at Namık Kemal Üniversitesi in Tekirdağ, Turkey. The visitation numbers of four categories of bees, Systropha planidens, Systropha curvicornis, Apis mellifera, and “other bees”, were recorded in each quadrat for two minutes. Although Convolvulus opened at approximately 7:00 and closed by 14:00, the nectar levels occurred in a smaller time frame, peaking at 8:00 and zeroing approximately at 11:00. Systropha exhibited peak visitation levels that lasted from approximately 9:00 to 11:00. This finding suggests that closing time is determined by another environmental factor or by the intrinsic clock of the flower. Meanwhile, the peak of Apis mellifera visitations varied on each day of the study. The early visitation time of Systropha may be to avoid competition with other bees for the nectar from Convolvulus. We can infer that light intensity is an influential factor in Convolvulaceae rhythmic behavior.
