![]() Patterns of foraging specialization over different timescales have important implications for how individuals and, for social bee species, colonies manage the collection of multiple floral rewards. Yet almost no research has examined specialization by the same foragers over different timescales. ![]() These and other studies suggest that patterns of foraging task specialization by individual worker bees might differ when we examine the short term (e.g., hours or days) versus the long-term (e.g., lifetime). In fact, intrinsic differences among foragers are thought to explain lifetime patterns of specialization on the collection of nectar, water, and pollen in foraging honeybees 9, 10. In addition, individuals can vary in their task performance as a result of fixed physiological or morphological differences for example, honeybees vary in their sucrose sensitivity 4, 9. Cognitive costs associated with learning and recalling such collection routines are thought to make it advantageous for foraging bees to specialize in the short term on a given plant species 3, 4, 5, 6, 7, 8. For instance, bees often have to learn new nectar collection routines each time they shift to a new plant species 3, 7. Because switching between tasks can incur temporal, cognitive, and/or energetic costs, specialization is thought to maximize task efficiency 3, 4, 5, 6. Specialization on different foraging tasks in particular has been well studied (e.g., refs 3 and 4). Eusocial bees, some of our most important pollinators, must engage in a variety of tasks over their lifetime, including nest construction, brood care, and foraging from flowers to feed themselves and their nest mates. Task specialization is a hallmark of insect societies 1, 2. We discuss causes and functions of short and long-term patterns of specialization for bumblebee colonies. Contrary to expectations, daily and lifetime reward specialists were not better foragers (being neither larger nor making more bouts) larger bees with more antennal olfactory sensilla made more bouts, but were not more specialized. Only a small proportion of foragers were lifetime specialists nevertheless, >50% of foragers specialized daily on a given reward. In particular, we described antennal morphology and size of all foragers in a single colony and related these factors to each forager’s complete foraging history, obtained using radio frequency identification (RFID). We also explored factors that govern such patterns, and asked whether reward specialists made more foraging bouts than generalists. We asked whether bumblebees specialize over timescales shorter than their lifetime. Eusocial bees in particular must collect pollen and nectar rewards to survive, but most workers appear to mix collection of both rewards over their lifetimes. While much research has focused on improvements associated with lifetime task specialization, members of colonies can specialize on a given task over shorter time periods. The ecological success of social insects is frequently ascribed to improvements in task performance due to division of labour amongst workers.
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