Foraging patterns of bees on watermelon (Citrullus lanatus Thunb.) flowers in Panama

Watermelon is one of the most important fruit crops in the world, but their flowers require bees for pollination. In this study we determine bee species visiting watermelon flowers, their daily visits and the resource they forage during 84 observation days on crops in Los Santos, Panama. Native bees, especially stingless bees represented most of the visits, so they probably play a very important role on the pollination of the crops within the zone. The most frequent bee species visiting flowers were N. perilampoides (58.7%), A. mellifera (23%), and P. peckolti (4%). Most of the bees foraged nectar, with very similar numbers between staminate and pistillate flowers. Honeybees dedicated almost half of their visits (47.7%) for pollen collection, and made most of their daily visits between 7:00 and 8:00 hours, whereas stingless bees visits picked up between 8:00 and 9:00 hours. Nectar visits were shorter than pollen visits, and overall, honeybees made the shortest visits to watermelon flowers. We found significant differences in the daily foraging patterns between bee species foraging for resources during the 84 observation period (Friedman P<0.05). We also found bee characteristics (size, color and sociability) and hour of the day significantly influenced flower visits for resources (GLMM P<0.05). Our results can be useful for predicting behavior of some of the Central American bee species, and managing and protecting those species, and improving fruit production in local watermelon crops.