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Of the 265 known bumble bee (Bombus) species, knowledge of colony lifecycle is derived from relatively few species. As interest in Bombus commercialization and conservation grows, it is becoming increasingly important to understand colony growth dynamics across a variety of species since variation exists in nest success, colony growth, and reproductive output. In this study, we reported successful nest initiation and establishment rates of colonies and generated a timeline of colony development for 15 western North American Bombus species, which were captively reared from wild-caught gynes from 2009 to 2019. Additionally, we assessed variation in colony size among 5 western North American Bombus species from 2015 to 2018. Nest initiation and establishment rates varied greatly among species, ranging from 5–76.1% and 0–54.6%, respectively. Bombus griseocollis had the highest rates of nest success across the 11-yr period, followed by B. occidentalis , B. vosnesenskii , and B. huntii. Furthermore, days to nest initiation and days to nest establishment varied among species, ranging from 8.4 to 27.7 days and 32.7 to 47 days. Colony size also differed significantly among species with B. huntii and B. vosnesenskii producing more worker/drone cells than B. griseocollis , B. occidentalis , and B. vancouverensis. Additionally, gyne production differed significantly among species with B. huntii colonies producing more gynes than B. vosnesenskii. Results from this study increase knowledge of systematic nesting biology for numerous western North American Bombus species under captive rearing conditions, which can further improve rearing techniques available to conservationists and researchers. [ABSTRACT FROM AUTHOR]

Foraging behaviors of bumble bee workers have been examined in natural habitats, whereas agricultural landscapes, which can provide insights on flight distances to fragmented patches of bloom, have received limited attention. In particular, information on worker flight distances to crops blooming several months after nests have been established is invaluable. Here, we examined foraging patterns of Bombus vosnesenskii Radoszkowski in late-season blooming clover in the agricultural- dominated Willamette Valley in Oregon. Workers from 10 fields collected over 2 yr were assigned to full sibling families (colonies) by using eight microsatellite loci. With estimation of numbers of unseen species, we inferred the presence of 189 colonies from 433 bees genotyped in year 1, and 144 from 296 genotyped the next year. Worker foraging distance was estimated to be at least 11.6 km, half the distance between the most remote fields visited by the same colonies. Numbers of nests contributing workers to each field ranged from 15 to 163. Overall, 165 (50%) colonies foraged in two or more fields, and thus used common resources within the landscape. Estimates of average nest densities in the landscape each year ranged from 0.76/km² to 22.16/km² and highlighted the influences of various study parameters incorporated into the calculation including sample size, distances between sites, and analytical tools used to estimate unsampled individuals. Based on the results, bumble bees can fly long distances, and this could facilitate their survival in fragmented agricultural landscapes. This has important implications for the scale of habitat management in bumble bee conservation programs. [ABSTRACT FROM AUTHOR]