Native bee populations are critical sources of pollination. Unfortunately, native bees are declining in abundance and diversity. Much of this decline comes from human land-use change. While the effects of large-scale agriculture on native bees are relatively well understood, the effects of urban development are less clear. Understanding urbanity's effect on native bees requires consideration of...

Some microsporidian parasites belonging to the genus Nosema infect bees. Previous phylogenies of these parasites have produced alternative, conflicting relationships. We analyzed separately, and in combination, large and small subunit ribosomal DNA sequences of Nosema species infecting bees under neighbor-joining, maximum parsimony, maximum likelihood, and Bayesian frameworks. We observed a sis...

Pathogens have been implicated as potential factors in the recent decline of some North American bumble bee (Bombus) species, but little information has been reported about the natural enemy complex of bumble bees in the United States. We targeted bumble bee populations in a state-wide survey in Illinois and several sites in California and Oregon where declines have been reported to determine p...

1. There is growing interest in improving the biodiversity of urban and suburban areas. Here we report on the effectiveness of a very simple intervention that may be used to boost flower and pollinator abundance; the sowing of plots of wildflowers in amenity grasslands. The abundance of flowers, bumblebees (Bombus spp.), and hoverflies (Syrphidae) was surveyed in 30 such plots, either 1 or 2 ye...

Many bumblebee (Bombus) species are thought to have declined in abundance in the last 50 years, while a small number of species remain abundant. Here we examine which factors render some British bumblebee species more susceptible to environmental change than others. We present forage data on workers of 15 bumblebee species gathered from 172 one hour searches conducted at sites in southern UK, t...

The Palaearctic Bombus ruderatus (in 1982/1983) and Bombus terrestris (1998) have both been introduced into South America (Chile) for pollination purposes. We here report on the results of sampling campaigns in 2004, and 2010-2012 showing that both species have established and massively expanded their range. Bombus terrestris, in particular, has spread by some 200 km year(-1) and had reached th...

Electrophoretic analysis of extracts of 12 bumblebee species revealed complex patterns of extramitochondrial diphosphopyridine nucleotide-dependent glycerol 3-phosphate dehydrogenase (EC 1.1.1.8) variants. Most Bombus species show one pattern, while Bombus nevadensis has a second and Bombus occidentalis a third pattern. All three Psithyrus (i.e. parasitic bumblebee) species tested have a fourth...

Bumblebees are ecologically and economically important, and some species have suffered dramatic population declines. The absence of morphological diagnostic characters for the identification of some species creates difficulties for basic ecological studies, and for conservation management. The widespread and commercially exploited bumblebee subgenus ​Bombus sensu stricto​ contains a cryptic spe...