Honeybee foraging in differentially structured landscapes

Ingolf Steffan-Dewenter , Arno Kuhn

Abstract

Honeybees communicate the distance and location of resource patches by bee dances, but this spatial information has rarely been used to study their foraging ecology. We analysed, for the first time to the best of the authors' knowledge, foraging distances and dance activities of honeybees in relation to landscape structure, season and colony using a replicated experimental approach on a landscape scale. We compared three structurally simple landscapes characterized by a high proportion of arable land and large patches, with three complex landscapes with a high proportion of semi–natural perennial habitats and low mean patch size. Four observation hives were placed in the centre of the landscapes and switched at regular intervals between the six landscapes from the beginning of May to the end of July.

A total of 1137 bee dances were observed and decoded. Overall mean foraging distance was 1526.1 ± 37.2 m, the median 1181.5 m and range 62.1–10 037.1 m. Mean foraging distances of all bees and foraging distances of nectar–collecting bees did not significantly differ between simple and complex landscapes, but varied between month and colonies. Foraging distances of pollen–collecting bees were significantly larger in simple (1743 ± 95.6 m) than in complex landscapes (1543.4 ± 71 m) and highest in June when resources were scarce. Dancing activity, i.e. the number of observed bee dances per unit time, was significantly higher in complex than in simple landscapes, presumably because of larger spatial and temporal variability of resource patches in complex landscapes. The results facilitate an understanding of how human landscape modification may change the evolutionary significance of bee dances and ecological interactions, such as pollination and competition between honeybees and other bee species.