Speed-accuracy trade-off and its consequences in a scramble competition context

摘要

Animals foraging in groups commonly respond to the presence of others by increasing their foraging rate, an increase that could come at the expense of prey detection accuracy. Yet the existence and consequences of such so-called 'speed-accuracy trade-offs' in group-foraging animals remain unexplored. We used group-feeding zebra finches, Taeniopygia guttata, to determine how search speed affects food detection accuracy and how a potential speed-accuracy trade-off influences feeding success. We found significant between-individual differences in hopping speed as well as evidence that faster individuals were more likely to overlook food, demonstrating the existence of a trade-off between speed and food detection probability. We also found that feeding success was positively predicted by an individual's food detection probability, whereas it was unrelated to hopping speed. These findings have several implications. First, they indicate that social animals, like solitary foragers, may be affected by perhaps universal constraints when foraging, such as limited attention. These constraints may contribute to promote between-individual variation in foraging tactics within social groups. Second, the existence of a speed -accuracy trade-off suggests that between-individual behavioural differences are more likely to come from differential allocation between speed and accuracy than from differences in general intrinsic abilities to exploit food resources. Finally, scramble competition's outcomes are likely to be determined by a combination of foraging abilities that individuals must trade off against one another, calling for an integrative approach of how natural selection shapes interactive behavioural dimensions during foraging.