Data for Will et al. 2025 Standard metabolic rate is repeatable, but does not affect call characteristics, in the gray treefrog Hyla chrysoscelis

Consistent among-individual variation in behavior is widespread and often has consequences for fitness. However, the mechanistic basis of repeatable variation in behavior is less understood. Metabolic rate is a likely candidate to drive repeatability in behavior because energy metabolism can limit behavioral expression. There are competing hypotheses for the relationship (or lack thereof) between levels of maintenance metabolism such as standard metabolic rate (SMR) and the expression of behaviors. On the one hand, SMR may show a negative relationship with behavior if higher SMR limits energy that can be allocated to other processes. On the other hand, SMR may positively correlate with behavior if high SMR leads to greater energy production ability. To test these hypotheses, we examined the relationship between SMR and repeatable, highly energetically costly sexual signals in male Cope’s grey treefrogs (Hyla chrysoscelis). We recorded individual male acoustic advertisement calls in the field and measured their SMR the following day. We made repeated measurements of SMR across multiple captures of the same individuals to assess the repeatability of metabolic rates, and whether consistency in SMR decreases over time. There was no evidence that SMR affected call characteristics in H. chrysoscelis. Nevertheless, SMR was significantly repeatable. We found that SMR decreased across the breeding season, which reduced the consistency in SMR measurements of the same individual over time. We conclude that calling in H. chrysoscelis does not provide information to mates or rivals on male SMR, although other aspects of metabolism may still drive individual variation in calling.