Effect of the type and degree of floral symmetry on bumble bee flower choice and foraging behaviour.

摘要

Three experiments were conducted, using bumble bees (Bombus impatiens), to determine if their documented preference for bilateral flower types and flowers with a low degree of asymmetry were innate or learned and if a proximal cause of the observed preferences is a result of asymmetry in ultraviolet nectar guides on an asymmetrical flower. The first experiment tested for an innate preference for a particular type and degree of symmetry. I predicted that bumble bees would show an innate preference for bilateral flowers over radial flowers and symmetrical over asymmetrical flowers. The bumble bees showed no innate preference for a particular type or degree of symmetry.;The second experiment was conducted to test for biased learning for symmetrical flowers. I predicted that bees would remember symmetrical flowers better than asymmetrical flowers after 1 hour. Bees visited more rewarding flowers when tested on bilateral than radial flowers. However, no biased learning or memory for symmetrical flowers was exhibited by the bumble bees in this experiment.;The third experiment was conducted to determine if bumble bees were sensitive to asymmetry in ultraviolet nectar guides. Handling time was greater for bees tested on radial than bilateral flowers and asymmetrical than symmetrical flowers. Foraging rate per flower tended to be faster on bilateral flowers, although bees tested on radial flowers with equal nectar guides were as fast as bees tested on bilateral flowers with equal and unequal nectar guides. There was no difference in the foraging rate of bees tested on symmetrical and asymmetrical bilateral flowers, however, bees foraged more quickly on symmetrical radial flowers than asymmetrical radial flowers. (Abstract shortened by UMI.).