Bumblebee ecology in relation to the pollination of alfalfa and red clover

Abstract

The ecology of bumblebees has been discussed under two major headings: (1) floral hosts and (2) populations. An understanding of the environmental factors that (1) affect the behavior of bumblebees in visiting flowers and (2) influence the production of a worker field force are basic to the utilisation of bumblebees in a practical way for the increased pollination, or more consistent pollination of alfalfa and red clover seed crops. Information is presented about the host plants in their seasonal succession, and the attractiveness of various flowers during the period of worker activity. Certain species of bumblebees are shown to differ in their preference of red clover and alfalfa. The initiation of colonies, the proper development of the brood, and the production of the workers have been related with ecological factors having major influence. Optimum conditions will be required for the culmination of a colony in a maximum force of worker bees at peak availability for pollination. Worker populations vary widely between species and among colonies of the same species. An elucidations of the reasons for the fluctuations will require additional biological and ecological research.