No Evidence of Terminal Investment in the Gray Treefrog (Hyla versicolor): Older Males Do Not Signal at Greater Effort

Current models indicate that life history trade-offs between current and future reproduction can have a major influence on sexual signaling. Individuals with fewer future reproductive opportunities—regardless of current effort—are expected to allocate greater resources to current reproductive effort (terminal investment) because of the low marginal survival cost to signaling. In this study we examined the effect of age and physical condition on the calling behavior of the Gray Treefrog (Hyla versicolor) to test the prediction that older males should exhibit greater signaling efforts compared to younger males of similar condition. Contrary to our predictions, calling males showed no significant effect of age or condition on any of the three call properties measured (call length, call rate, call effort). We offer possible explanations for the apparent discrepancy between theoretical predictions and our observations from the field.