Abstract
BackgroundAccurate estimates of movement behavior and distances travelled by animals are difficult to obtain, especially for small-bodied insects where transmitter weights have prevented the use of radio-tracking.Methodology/Principal FindingsHere, we report the first successful use of micro radio telemetry to track flight distances and space use of bumblebees. Using ground surveys and Cessna overflights in a Central European rural landscape mosaic we obtained maximum flight distances of 2.5 km, 1.9 km and 1.3 km for Bombus terrestris (workers), Bombus ruderatus (worker), and Bombus hortorum (young queens), respectively. Bumblebee individuals used large areas (0.25–43.53 ha) within one or a few days. Habitat analyses of one B. hortorum queen at the landscape scale indicated that gardens within villages were used more often than expected from habitat availability. Detailed movement trajectories of this individual revealed that prominent landscape structures (e.g. trees) and flower patches were repeatedly visited. However, we also observed long (i.e. >45 min) resting periods between flights (B. hortorum) and differences in flower-handling between bumblebees with and without transmitters (B. terrestris) suggesting that the current weight of transmitters (200 mg) may still impose significant energetic costs on the insects.Conclusions/SignificanceSpatio-temporal movements of bumblebees can now be tracked with telemetry methods. Our measured flight distances exceed many previous estimates of bumblebee foraging ranges and suggest that travelling long distances to food resources may be common. However, even the smallest currently available transmitters still appear to compromise flower handling performance and cause an increase in resting behavior of bees. Future reductions of transmitter mass and size could open up new avenues for quantifying landscape-scale space use of insect pollinators and could provide novel insights into the behavior and requirements of bumblebees during critical life stages, e.g. when searching for mates, nest locations or hibernation sites.
Highlights
Quantifying animal space use is fundamental for understanding population processes and for developing conservation and agricultural management plans
Whether these young queens were gynes or pre-hibernation mated queens remains unknown.While B. terrestris and B. hortorumare very common species in Europe that are found in gardens, orchards or parks, B. ruderatus is rather rare and distributional data are limited due to its resemblance to B. hortorum[37]
The scarce data on live:dry mass ratios suggest that the live masses of bumblebees are about two- to threefold higher than their dry weights[39], even though live mass is highly variable due to e.g. nectar intake
Summary
Quantifying animal space use is fundamental for understanding population processes and for developing conservation and agricultural management plans. In areas with intensive agriculture, several solitary bee species are highly threatened [4,5] and recently documented declines in bee diversity [6] illustrate the urgent need to improve our understanding of how insect pollinators move on a landscape scale. Population declines in bumblebee species, a highly important pollinator group [7,8,9], have been attributed to a reduced availability of suitable food resources in agricultural landscapes [10,11], a reduction in nesting and hibernation sites [10,12], competition from introduced species [13], and potential pathogen spillover from commercially reared colonies [14]. Accurate estimates of movement behavior and distances travelled by animals are difficult to obtain, especially for small-bodied insects where transmitter weights have prevented the use of radio-tracking
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
