Meeting Abstract
What factors determine where animals choose to forage in the face of uncertain food rewards? Foragers face a challenging problem – visit the best known location or explore new locations where rewards are uncertain. Though theoretical approaches suggest that foragers may decrease exploration over time, few experiments have explicitly examined animals’ strategies in uncertain environments. Of the experiments that have been conducted, many allow foraging insects to visit flowers to collect nectar. Though many insects require both nectar and pollen to survive, pollen-foraging is understudied. Bumblebees provide an ideal system to study pollen-foraging, because their pollen-collecting behavior (floral sonication) can be easily quantified. They vibrate their flight muscles to shake pollen from flowers, suggesting that floral sonication is likely more energetically costly than nectar foraging. Using accelerometers, we built an automated system to quantify bees’ transitions between flowers – one flower delivered pollen when sonicated and another did not. We found transitions between the two flowers were rare (initially 5-10%). Over time, however, the chance of transitioning from the unrewarding flower to the rewarding flower increased (from 9% to 27%), and the probability of staying on the unrewarding flower decreased (from 89% to 72%). Bees did not visit the rewarding flower exclusively but maintained a constant ~6% chance of transitioning away from the rewarding flower (i.e. exploring the environment). This may be an adaptive strategy to keep bees from missing out on flowers that release pollen at different times of the day or to keep bees from continuing to visit flowers that are releasing diminishing resources. Overall, this work fills a knowledge gap, to help us understand how pollinators make decisions when foraging for pollen as they gain experience in an uncertain environment.
