Meeting Abstract
Signals, resilience to stress, and social behavior can be dynamically linked. For example, social interactions influenced by signals may exacerbate or buffer the effect of stressors, while at the same time stress may alter signals. To date, few studies have examined these possibilities in natural populations. We imposed stressful conditions on female tree swallows by reversibly attaching groups of feathers on each wing during incubation. This treatment reduces flight efficiency, thereby increasing the energetic costs of foraging. We also monitored social activity using a network of RFID units that allowed us to track the identity of every individual that visited each nest box. Relative to controls, stressed females were more likely to abandon their nest during incubation. Overall, females with brighter white breasts were less likely to abandon, but this pattern was only significant under stressful conditions. In addition to being more resilient to stress treatments, females with brighter white breast feathers received more unique male and female visitors at their nest box and made more visits to other active nests in the population, suggesting that these females were more socially active and integrated into the breeding population. In contrast, dorsal coloration did not reliably predict abandonment or social interactions. Taken together, our results suggest that ornaments, resilience, and social behavior are linked. The interaction between treatment and color in predicting abandonment also suggests that the marginal costs of stressors depend on signaling phenotype; differential costs are a key feature of many models of signal honesty, but have only rarely been demonstrated empirically. Ongoing work is focused on elucidating the mechanistic basis for the links demonstrated here and the extent to which causality is multidirectional.
