To innovate or not: contrasting effects of social groupings on safe and risky foraging in Indian mynahs

Foraging innovations are increasingly recognized as an important source of phenotypic plasticity, evolutionary change and adaptation to environmental challenges. One line of research has successfully demonstrated that innovation can represent a stable individual trait, but by the same token has shown strong contextual effects on innovation. We examined the effects of social context on innovative foraging behaviour. Across two separate experiments, we measured the individual propensity of Indian mynahs, Acridotheres tristis, to innovate when alone, in pairs, or in groups of five birds. Although innovators remained consistent in their relative innovation performance ranking (high, medium, low), the presence of one or more conspecifics reduced the likelihood of innovating, and increased innovation latencies, significantly relative to when individuals were tested alone. A neophobia test in which latency to forage was compared in both the absence and the presence of a novel object, in each of two social contexts (solitary versus social), showed that the presence of conspecifics caused mynahs to forage significantly faster in a safe situation (object absent) relative to when alone, but to delay foraging in a risky situation (object present). Together, these findings suggest that sociality can have contrasting effects on foraging in safe and risky situations, and, in some species at least, effects of sociality on innovative foraging may hence be more akin to those observed in the presence of risk. Negotiation over engaging with risks inherent to innovative foraging offered the most likely explanation for socially inhibited innovation behaviour, and may act to constrain the diffusion of innovations under some conditions.