Submitted to: Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/29/2009
Publication Date: 1/8/2010
Citation: Strange, J.P. 2010. Nest Initiation in Three North American Species of Bumble Bees (Bombus): Effects of Gyne Number and Worker Helpers on Colony Size and Establishment Success. Insect Science 10:1-11. Interpretive Summary: Three species of bumble bees were evaluated for a trait that is important in commercializing a species: nest initiation by queens. Queen bumble bees start colonies in the spring and can be trapped and made to form colonies in the laboratory for use in greenhouses and crops. The present study tests three ways of inducing queens to initiate nests in captivity. Many researchers have tried to get bumble bee queens to found nests by themselves, but the success rate is low, generally less than 20%. By manipulating the number of queens in a nest, or by adding honey bee workers to the nest, the success rate in the present study increased dramatically. Two queens placed in a starter box together were four times more likely to start a nest than a single unaided queen. A queen placed in the starter box with two honey bee workers was twice as likely to found a nest as a single unaided queen. The trend was similar with all three species evaluated suggesting that the techniques may be broadly applicable when rearing bumble bees. These techniques are important in helping bumble bee producers and researchers develop species for pollination.
Technical Abstract: Three species of bumble bees, Bombus appositus, B. bifarius, and B. centralis (Hymenoptera: Apidae) were evaluated for nest initiation success under three sets of initial conditions. In the spring, queens of each species were caught in the wild and introduced to nest boxes in one of three ways. Queens were either introduced in conspecific pairs, singly with two honey bee (Apis mellifera L.) workers, or alone. Nesting success and colony growth parameters were measured to understand the effects of the various treatments on nest establishment. Colonies initiated from pairs of conspecific queens were most successful in producing worker bees (59.1%), less successful were colonies were initiated with honey bee workers (34.8%), and least successful were bumble bee queens initiating colonies alone (16.1%). There was a negative correlation between the numbers of days to the emergence of the first worker in a colony to the attainment of ultimate colony size, indicating that queens that have not commenced oviposition in 21 days are unlikely to result in colonies exceeding 50 workers. B. appositus had the highest rate of nest establishment followed by B. bifarius and B. centralis. Nest establishment rates in three western bumble bee species can be increased dramatically by the addition of either honey bee workers or a second queen to nesting boxes at colony initiation.