Pollinator-plant interactions: does the size of the inflorescence of Melilotus alba (white sweet clover) affect the foraging behavior of bumble bees?

Abstract

Lack of information concerning the affect of inflorescence size on insect foraging behaviors and whether these foraging behaviors aid in self or cross pollination prompted this investigation. My main objectives were: to determine if the inflorescence size causes a difference in the insect visitation on white sweet clover, and to examine if size of inflorescence encourages more self or cross pollination. I observed thirteen bumblebees making note of the number of flowers they foraged on and each of their movements within or between plants. The bees visited more flowers on larger inflorescences than smaller inflorescences. The chi-squared analysis did not show a significant difference in the way the bees foraged on large and small inflorescences. However, a general trend existed in which the bees foraging on smaller inflorescences seemed to have more between plant movements than within plant movements. This may inply that smaller inflorescences encourage more cross-pollination than larger ones.