Frequencies of Diploid Males in Natural Populations of Three North American Bumble Bee (Bombus) Species (Hymenoptera: Apidae)

We used four DNA microsatellite markers and detected diploid males in two out of three species of North American bumble bees from Alberta, Canada. The estimated average proportion of diploid males, , in Bombus occidentalis Greene and Bombus perplexus Cresson was ≈ 3% (n = 112) and 6% (n = 104), respectively. However, there was no significant difference between these estimates. Because no diploid males were detected in the sample (n = 81) of Bombus terricola Kirby, no estimate of could be made directly, but the upper limit to that would be found in a sample of this size, was ≈ 4%. The average over the three species was ≈ 4%. This is the first report of diploid males in natural populations of North American bumble bees.