Faculty Sponsor
Aimee Dunlap
Final Abstract for URS Program
Bumble bees (Bombus impatiens) are crucial pollinators, responsible for pollinating multiple native plants and agricultural crops. Caffeine, which is classified as a stimulant, is present in some of these plant species at varying levels. Alterations in bumble bee cognition, including motivation, learning, and hunger, have been associated with caffeine intake. This study explored the impacts of caffeine on the bumble bee behavior on a biological level. While previous research has examined caffeine’s effects on cognition and learning, fewer studies have investigated its effects on hunger at the level of individual bees. Bumble bees, identified with numerically labeled tags, were trained to forage on a single artificial flower within a transparent apparatus. Individual bumble bees were then pretreated with 5 µl of a randomly assigned treatment: a control (containing 60% sucrose solution) or one of four caffeine concentrations (0.01 M, 0.001 M, 0.0001 M, or 0.00001 M) dissolved in 60% sucrose solution. The bumble bees were also randomly assigned to a progressive or fixed ratio schedule of reward. Fifteen minutes after pretreatment, bumble bees were introduced to the testing apparatus and were provided 5 µl of 60% sucrose solution as a reward. The progressive ratio schedule required an increasing number of visits per reward over time, while the fixed ratio schedule supplied the bumble bee with a reward for each visit. Hunger was assessed by calculating sucrose consumption relative to thorax width for each treatment.
The goal of this study was to establish whether exposure to different levels of caffeine when foraging alters hunger and feeding behavior in bumble bees. These findings will be discussed in the context of recent studies conducted in our lab.
Presentation Type
Visual Presentation
Document Type
Article