We analyzed the effects of queen removal on male and queen production in the bumble bee, Bombus terrestris. In total, 43 Bombus terrestris colonies were reared under standard laboratory rearing conditions. Before the competition point, when the colonies comprised 35-40 workers and many diploid larvae, we removed the queens from 20 randomly selected colonies to test the effects of queenlessness. The timing of gyne production in queenless colonies (25.6 +/- 1.5 days) was significantly earlier than in queenright colonies (32.8 +/- 3.2 days). Although queen removal had a significant effect on the timing of gyne production, there was no significant difference between the timing of the switch point, or the number of gynes and males produced in the queenright and queenless colonies.