Electronic Thesis and Dissertation Repository

Degree

Doctor of Philosophy

Program

Psychology

Supervisor

Sherry, David F.

Abstract

Foraging bumblebees (Bombus impatiens) extract nectar and pollen from a wide variety of morphologically distinct flower species, referred to as flower handling. Bumblebees learn this behaviour and acquisition of multiple flower handling techniques is a demonstration of behavioural flexibility. The purpose of this thesis is to understand how bumblebees are able to forage flexibly. This research has three specific goals: (1) to identify the cognitive mechanisms that support flower handling learning, (2) to understand how bumblebees avoid interference costs between multiple handling techniques, and (3) to explore the relation between behavioural flexibility and the mushroom bodies of the bumblebee brain. To address the first two goals, I developed a laboratory model of flower handling. The model consisted of a tube with a plastic door insert that bumblebees moved to access a nectar reward. The door was designed to be similar to a flower petal that a bee would lift to access a nectary in a real flower. All bees demonstrated the same set of motor behaviours and showed improvement across trials by increasing the frequency with which they used the successful behaviour. The apparatus was then adapted to measure bees’ ability to switch between two handling tasks, representing two different flower morphologies. Two variations of the apparatus were used, each of which required a different innate motor pattern for successful removal of the door. Bees switched between the two tasks by changing only the frequency that they engaged in each successful motor behaviour. The role of the mushroom bodies in behavioural flexibility was examined by training bees on a measure of behavioural flexibility, reversal learning, and relating performance to volume of the mushroom bodies and their components. Performance on the reversal task did not correlate with mushroom body volume. My overall findings are that bumblebees use a combination of innate motor patterns and learned associations to forage on a variety of flower species and the flexibility of individual bumblebees is not related to individual variation in volume of the mushroom bodies and their components.

Download

Share

COinS