The interaction of temperature and sucrose concentration on foraging preferences in bumblebees
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Several authors have found that flowers that are warmer than their surrounding environment have an advantage in attracting pollinators. Bumblebees will forage preferentially on warmer flowers, even if equal nutritional reward is available in cooler flowers. This raises the question of whether warmth and sucrose concentration are processed independently by bees, or whether sweetness detectors respond to higher sugar concentration as well as higher temperature. We find that bumblebees can use lower temperature as a cue to higher sucrose reward, showing that bees appear to process the two parameters strictly independently. Moreover, we demonstrate that sucrose concentration takes precedence over warmth, so that when there is a difference in sucrose concentration, bees will typically choose the sweeter feeder, even if the less sweet feeder is several degrees warmer.
KeywordsPollination Sensory ecology Sensory integration Sweetness detection
We thank Tom Collett and Simon Laughlin for discussions and Lucy Sandbach and David Prince for help with data collection. The project is funded by NERC grant NE/C000552/1. AGD is supported by ARC DP0878968.
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