Environmental conditions and bee foraging on watermelon crops in Panama

Abstract

Watermelon is a crop highly dependent on bees for pollination, and environmental conditions are some of the most important factors affecting bee foraging. In this study, we analyze the effect of environmental conditions on the behavior of the most common bees visiting flowers of watermelon crops in Panama. We recorded the number of visits, visit duration, and the corresponding environmental conditions during the visits. Environmental conditions affected the observed groups of bees differently: honey bee visit proportion was remarkably higher at low temperatures, solar radiation, wind speed, and high relative humidity, early in the morning when they made about 90% of their flower visits. The other observed bees showed a more homogenous behavior during the day, with peaks representing about 25-35% of the daily visits. Visit number showed a correlation with temperature for all the most common bees except Augochloropsis spp., with solar radiation for A. mellifera and Lasioglossum spp., with humidity for all except Lasioglossum spp., and with wind speed for all of the analyzed bees. Visit durations were remarkably longer in N. perilampoides early on the day. At the same time, the rest of the bees showed less pronounced duration peaks, reaching their maximum at intermediate values of environmental conditions. Visit duration on honeybees did not correlate with environmental factors, but it did for most other bees. Environmental conditions showed a strong effect on the bee foraging behavior, with each group of bees concentrating their activities in favorable conditions depending on their biology, establishing their daily foraging patterns.