1976] Waddington — Foraging Patterns of Halictid Bees 
115 
Results 
Bindweed plants grow along the ground, often forming dense 
tangled mats, and produce white or pinkish funnelform flowers. 
On test days anthesis began at about 0715 h and most flowers were 
fully open by 0800 h. Nectar was produced at the base of the corolla 
and pollen was slowly dehisced by the 5 anthers during the morning. 
The flowers wilted in the early afternoon. 
Halictid bees began visiting the bindweed before 0800 h and 
continued until nearly 1130 h when most of the nectar and pollen 
was depleted. During the first and last half hour of the foraging 
periods visits were infrequent. Censusing was conducted from 
about 0830 to 1030 h when halictid activity was generally high 
(Fig. 1). 
The number of bees per quadrat is the Poisson variable for both 
the temporal and spatial quadrat sampling experiments. If the 
observed frequencies closely fit the expected Poisson distribution 
with the same mean (x), indicating the bees are randomly dispersed 
over the flowers, then it can be assumed that the bees are foraging 
25 
0730 0830 0930 1030 
Time(Hrs-) 
Fig. 1. Visitation frequency of Halictid bees to quadrates 4-7 (data pooled) be- 
tween 0730 and 1 130 h, July 2. Each bar is the sum of bees during three consecutive 
censuses. 
