I spent some
time watching a colony of Colletes Cunicularius at Whiteford 2 weeks ago.
I was
curious to find out why some of the males 2 or 3 at a time, were digging at one
particular place in the sand for maybe 5-10 minutes and then as if bored of
doing so flew away to some other places. I took a twig and started to dig
where these males had started a tiny hole. After reaching a couple of centimeters
down, a fully grown and emerging bee would come out and all
those observed (I dug 3 holes) were males. I concluded from these observations
that the digging males had detected an emerging bee at first but then must have
found out (via pheromones?) that it was a male not a female and had given up
digging as a result.
I also
observed some females being mated by the stronger of the fighting males. Some
males would try to push the stronger males out of the way but failed. When the
act was over, the male would fly away and the mated female was ignored by other
males. Somehow, the female had become unreceptive.
I have attached a couple of pictures below. One shows several males waiting for a female to emerge, note the smaller male behind the bigger males on the bottom left of the picture.
Sylvie Herault 
