Publications

Patterns of range-wide genetic variation in six North American bumble bee (Apidae: Bombus) species.	The increasing evidence for population declines in bumble bee (Bombus) species worldwide has accelerated research efforts to explain losses in these important pollinators. In North America, a number of once widespread Bombus species have suffered serious reductions in range and abundance, although other species remain healthy. To examine whether declining and stable species exhibit different levels of genetic diversity or population fragmentation, we used microsatellite markers to genotype popul ...	2011	22035452
landscape-scale resources promote colony growth but not reproductive performance of bumble bees.	variation in the availability of food resources over space and time is a likely driver of how landscape structure and composition affect animal populations. few studies, however, have directly assessed the spatiotemporal variation in resource availability that arises from landscape pattern, or its effect on populations and population dynamic parameters. we tested the effect of floral resource availability at the landscape scale on the numbers of worker, male, and queen offspring produced by bumb ...	2012	22764491
resource diversity and landscape-level homogeneity drive native bee foraging.	given widespread declines in pollinator communities and increasing global reliance on pollinator-dependent crops, there is an acute need to develop a mechanistic understanding of native pollinator population and foraging biology. using a population genetics approach, we determine the impact of habitat and floral resource distributions on nesting and foraging patterns of a critical native pollinator, bombus vosnesenskii. our findings demonstrate that native bee foraging is far more plastic and ex ...	2013	23267118
urban land use limits regional bumble bee gene flow.	potential declines in native pollinator communities and increased reliance on pollinator-dependent crops have raised concerns about native pollinator conservation and dispersal across human-altered landscapes. bumble bees are one of the most effective native pollinators and are often the first to be extirpated in human-altered habitats, yet little is known about how bumble bees move across fine spatial scales and what landscapes promote or limit their gene flow. in this study, we examine regiona ...	2013	23495763
three floral volatiles contribute to differential pollinator attraction in monkeyflowers (mimulus).	flowering plants employ a wide variety of signals, including scent, to attract the attention of pollinators. in this study we investigated the role of floral scent in mediating differential attraction between two species of monkeyflowers (mimulus) reproductively isolated by pollinator preference. the emission rate and chemical identity of floral volatiles differ between the bumblebee-pollinated mimulus lewisii and the hummingbird-pollinated m. cardinalis. mimulus lewisii flowers produce an array ...	2014	24198269
colony-level variation in pollen collection and foraging preferences among wild-caught bumble bees (hymenoptera: apidae).	given that many pollinators have exhibited dramatic declines related to habitat destruction, an improved understanding of pollinator resource collection across human-altered landscapes is essential to conservation efforts. despite the importance of bumble bees (bombus spp.) as global pollinators, little is known regarding how pollen collection patterns vary between individuals, colonies, and landscapes. in this study, vosnesensky bumble bees (bombus vosnesenskii radoszkowski) were collected from ...	2014	24763096
contemporary human-altered landscapes and oceanic barriers reduce bumble bee gene flow.	much of the world's terrestrial landscapes are being altered by humans in the form of agriculture, urbanization and pastoral systems, with major implications for biodiversity. bumble bees are one of the most effective pollinators in both natural and cultivated landscapes, but are often the first to be extirpated in human-altered habitats. yet, little is known about the role of natural and human-altered habitats in promoting or limiting bumble bee gene flow. in this study, i closely examine the g ...	2015	25626470
bombus huntii, bombus impatiens, and bombus vosnesenskii (hymenoptera: apidae) pollinate greenhouse-grown tomatoes in western north america.	bumble bees (bombus) are the primary pollinators of tomatoes grown in greenhouses and can significantly increase fruit weight compared with tomatoes that receive no supplemental pollination. more than a million colonies are sold worldwide annually to meet pollination needs. due to mounting concerns over the transportation of bumble bees outside of their native ranges, several species native to western north american are currently being investigated as potential commercial pollinators. here, two ...	2015	26470206
bumble bee colony dynamics: quantifying the importance of land use and floral resources for colony growth and queen production.	bumble bee (bombus) species are ecologically and economically important pollinators, and many species are in decline. in this article, we develop a mechanistic model to analyse growth trajectories of bombus vosnesenskii colonies in relation to floral resources and land use. queen production increased with floral resources and was higher in semi-natural areas than on conventional farms. however, the most important parameter for queen production was the colony growth rate per flower, as opposed to ...	2016	26913696