Effects of Experience on Short- and Long-term Foraging Performance in Bumblebees

The long-term effects of learning on performance are widely appreciated in humans (Ericsson et al. 2006), but have rarely been closely examined in other species. Long-term studies in several bird species have suggested that learning over years contributes to increased reproductive success (e.g. Nol & Smith 1987; Wooler et al. 1990; Daunt et al. 2007; Vieyra et al. 2009). The avian systems, however, are not amenable to the experimental manipulation necessary for critically examining how long-term experience enhances performance. In a series of studies, Dukas and colleagues (Dukas & Visscher 1994; Schippers et al. 2006; Dukas 2008b) documented in three different field sites and years that honeybees (Apis mellifera) foraging in natural settings exhibit a gradual improvement in performance such that they increase their rate of food delivery to the hive over much of their foraging life. Such lifetime performance curves are similar to the pattern known for birds and mammals including humans (Dukas 1998, 2008a; Helton 2008). Honeybees, however, only showed a rapid improvement followed by a long-term plateau in performance when they were allowed to forage on feeders placed 400 m from the hive, which provided unlimited volumes of sugar water (Dukas 2008a). The distinct lifetime patterns of performance in natural vs. artificial settings strongly suggested that bees foraging in the field learn a variety of tasks that together contribute to a gradual, long-term improvement in performance. Such tasks could include long-distance navigation, identification of the most profitable plant species, flower patches and perhaps individual plants in such patches, improved movements between flowers and plants, better flower handling techniques and superior motor skills. Evidence for short-term improvements owing to the factors just mentioned exists for both honeybees and bumblebees (e.g. Heinrich 1979; Laverty & Plowright 1988; Capaldi et al. 2000; Cartar 2004; Burns & Thomson Correspondence Reuven Dukas, Animal Behaviour Group, Department of Psychology, Neuroscience and Behaviour, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1. Email: [email protected]