An interspecific comparison of foraging range and nest density of four bumblebee (Bombus) species

Abstract

Bumblebees are major pollinators of crops and wildflowers in northern temperate regions. Knowledge of their ecology is vital for the design of effective management and conservation strategies but key aspects remain poorly understood. Here we employed microsatellite markers to estimate and compare foraging range and nest density among four UK species: Bombus terrestris, Bombus pascuorum, Bombus lapidarius, and Bombus pratorum. Workers were sampled along a 1.5-km linear transect across arable farmland. Eight or nine polymorphic microsatellite markers were then used to identify putative sisters. In accordance with previous studies, minimum estimated maximum foraging range was greatest for B. terrestris (758 m) and least for B. pascuorum (449 m). The estimate for B. lapidarius was similar to B. pascuorum (450 m), while that of B. pratorum was intermediate (674 m). Since the area of forage available to bees increases as the square of foraging range, these differences correspond to a threefold variation in the area used by bumblebee nests of different species. Possible explanations for these differences are discussed. Estimates for nest density at the times of sampling were 29, 68, 117, and 26/km2 for B. terrestris, B. pascuorum, B. lapidarius and B. pratorum, respectively. These data suggest that even among the most common British bumblebee species, significant differences in fundamental aspects of their ecology exist, a finding that should be reflected in management and conservation strategies.

Contemporary pollen flow, characterization of the maternal ecological neighbourhood and mating patterns in wild cherry (Prunus avium L.)

“…The maximum foraging ranges of four UK species of bumblebee (Bombus spp. ), which are one of the main pollinators of wild cherry, are estimated to range from 449 to 758 m (Knight et al, 2005) and recent evidence from radio tracking has showed that bee flight distances are significantly shorter in poor weather conditions (Pasquet et al, 2008). Foraging patterns across this range would account for the long-distance pollination events observed in our study.…”

Widespread contamination of wildflower and bee-collected pollen with complex mixtures of neonicotinoids and fungicides commonly applied to crops

“…proportion of OSR pollen was 10% in average for 475 honeybees as opposed to 32% in average for bumblebees). It may also be because bumblebees tend 476 to forage over shorter distances compared to honeybees (Knight et al, 2005), which may mean that 477 there is less dilution of pesticide residues coming in to the nest when these are located in the vicinity 478 of arable lands. However, it should be noted that our data set is small, and that honeybee hives and 479 bumblebee colonies were not placed in exactly the same localities.…”

Distribution and fine-scale spatial-genetic structure in British wild cherry (Prunus avium L.)

“…Preliminary direct gene-flow estimates from our study site suggest that the majority of pollination events occur between relatively close neighbours. Bumblebees (Bombus spp) are among the major pollinators for wild cherry and the maximum foraging ranges of four UK species have been estimated to range from 449 to 758 m (Knight et al, 2005). However, resource availability is a key factor influencing foraging and individual bees are likely to visit relatively few mature wild cherries before becoming satiated and returning to the nest, thus limiting pollen dispersal.…”