Sheila R. Colla

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Bumblebees (Bombus spp.) have been declining rapidly in many temperate regions of the Old World. Despite their ecological and economic importance as pollinators, North American bumblebees have not been extensively surveyed and their conservation status is largely unknown. In this study, two approaches were used to determine whether bumblebees in that region(More)
The phenology of many ecological processes is modulated by temperature, making them potentially sensitive to climate change. Mutualistic interactions may be especially vulnerable because of the potential for phenological mismatching if the species involved do not respond similarly to changes in temperature. Here we present an analysis of climate-associated(More)
Bumble bees are an important group of wild pollinators in North America and considerable concern has been expressed over declines in their populations. However, before causes for declines can be assessed, it is essential that the geographical and chronological patterns of decline be discovered. Hitherto a lack of assessment of historical data has hindered(More)
Parasites can affect host behavior in subtle but ecologically important ways. In the laboratory, we conducted experiments to determine whether parasitic infection by the intestinal protozoan Crithidia bombi or the tracheal mite Locustacarus buchneri alters the foraging behavior of the bumble bee Bombus impatiens. Using an array of equally rewarding yellow(More)
For many species, geographical ranges are expanding toward the poles in response to climate change, while remaining stable along range edges nearest the equator. Using long-term observations across Europe and North America over 110 years, we tested for climate change-related range shifts in bumblebee species across the full extents of their latitudinal and(More)
IN HER LETTER “Sexism discussion misses the point” (24 July, p. 390), H. S. Young advocates for improved infrastructure to assist women in the child-bearing years, when “research productivity needs to be the highest.” She contends that the lack of support mechanisms that enable women to work at this level is the substantial barrier that impedes women from(More)
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