Alfalfa and Red Clover as Sources of Nectar and Pollen for Honey, Bumble, and Leaf-cutter Bees (Hymenoptera: Apoidea)

The most important factor affecting the densities of pollinating species of bees on alfalfa seed fields in southern Alberta is competing flowering growth (Hobbs and Lilly, 1954, 1955). This is a report on the relative attractiveness of red clover and alfalfa to honey, bumble, and leaf-cutter bees in southern Alberta. Observations were made on the first crops grown in each of two newly cultivated and irrigated areas near Hays; the fields were isolated from all other entomophilous crops by at least five miles of virgin prairie. A third series of observations was made on crops grown in the isolated river valley near Lethbridge previously described by Hobbs and Lilly (1955).