Meeting Abstract
Circadian rhythm results from environmental factors and the intrinsic circadian clock of an organism. We studied two species of bees and common pollinators of the field (Convolvulus arvensis) flowers, Lasioglossum malachurum (generalist) and Systropha curvicornis (specialist) on Lesvos Island, Greece. C. arvensis produces flowers with an average life of less than 24 hours. Pollinators prefer to visit the flowers in early hours when rewards are most abundant. After observing these two species visit flowers, our goal was to compare the circadian rhythm of locomotor activity by these species. Bees were collected from two field sites and placed into an activity monitor to assay their circadian rhythms under controlled conditions in an environmental chamber. We tested the activity of both species inside the chamber under oscillating (simulated) field conditions and constant conditions by manipulating three factors; temperature, humidity and light. L. malachurum displayed high levels of activity throughout the 24-h period, with bimodal peaks in activity, consistent with our expectations for a generalist, social bee that forages and maintains a social nest. S. curvicornis displayed a discrete period of high activity slightly longer than the flowering time of C. arvensis. The circadian rhythm of S. curvicornis agrees with our expectations for a solitary specialist bee. Our comparison of these two bees reveals an interesting interplay among environmental conditions and bee life history that requires further study.
