Innovative consumers: ecological, behavioral, and physiological predictors of responses to novel food

Consumer innovation, that is, the acquisition and consumption of novel food types, has received little attention, despite its predominance among animal innovations and its potential implications for the ecology and evolution of species in a changing world. Results of the few studies that have investigated individual responses to novel foods suggest that various ecological, behavioral, and physiological variables may affect individual propensity for consumer innovation, but further work is needed to clarify these relationships. We investigated whether urbanization, social rank, exploratory personality, and baseline levels of corticosterone predict food neophobia and consumer innovation responses of wild-caught black-capped chickadees (N = 170) from 14 sites along an urbanization gradient. Our analyses do not support a link between food neophobia or consumer innovation and urbanization, dominance, or exploratory personality. However, birds with higher levels of baseline corticosterone were quicker to contact novel food types, and more likely to consume novel foods than individuals with lower levels of the hormone. This finding suggests that physiological states that promote foraging behavior might drive individual responses to novel food. Additionally, we found that chickadees tested later in autumn were less neophobic than those tested earlier in the season, perhaps reflecting seasonal changes in food availability. Together, the ability of baseline corticosterone and date of capture to predict responses to novel food suggest that necessity may drive consumer innovation in chickadees. Physiological state predicts the response of chickadees to new foods. After presenting birds with different types of novel food, we show that higher baseline levels of corticosterone are associated with decreased latency to contact these food items as well as a greater probability of consuming them. These results are in line with the known function of baseline corticosterone as a hormone that regulates metabolism and promotes foraging behavior in animals.