Spatial organization and division of labour in the bumblebee Bombus impatiens

Individuals in many types of animal groups show both reproductive and task-related division of labour. In some social insect species, such division of labour may be related to the spatial organization of workers inside the nest. We examined colonies of bumblebees and found that (1) 11-13% of workers maintained small spatial fidelity zones inside the nest, and all workers tended to remain at a specific distance from the colony centre independent of their age; (2) smaller individuals maintained smaller spatial zones and tended to be closer to the centre; and (3) individuals that were more likely to perform the in-nest task of larval feeding tended to remain in the centre of the nest, whereas foragers were more often found on the periphery of the nest when not foraging. Individuals that performed other tasks did not maintain a predictable distance to the centre, and there was no evidence that spatial preferences changed over time. Instead, spatial patterns may result from inherent differences between individuals in terms of activity level, and may be a self-organized sorting mechanism that influences division of labour among workers.