title: Nest initiation in three North American bumble bees (Bombus): gyne number and presence of honey bee workers influence establishment success and colony size.
abstract: Three species of bumble bees, Bombus appositus Cresson, Bombus bifarius, Cresson and Bombus centralis Cresson (Hymenoptera: Apidae) were evaluated for nest initiation success under three sets of initial conditions. In the spring, gynes of each species were caught in the wild and introduced to nest boxes in one of three ways. Gynes were either introduced in conspecific pairs, singly with two honey bees, Apis mellifera L. (Hymenoptera: Apidae) 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 gynes were most successful in producing worker bees (59.1%), less successful were colonies initiated with honey bee workers (33.3%), and least successful were bumble bee gynes initiating colonies alone (16.7%). 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 gynes 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 gyne to nesting boxes at colony initiation.
authors.affiliation: Pollinating Insect Research Unit, USDA-ARS, 255 BNR, Utah State University, Logan, Utah 84322-5310, USA. James.Strange@ars.usda.gov
authors.forename: James P
authors.initials: JP
authors.lastname: Strange
mesh_terms: D000818:Animals; D056630:Beekeeping; D001516:Bees; D005260:Female; D009425:Nesting Behavior; D011158:Population Growth; D013045:Species Specificity