Reproductive decision-making by female peacock wrasses: flexible versus fixed behavioral rules in variable environments

Because environments are temporally variable, animals may often estimate th e current environmental state to inform their behavioral choices. However, using experience may cause behavior to lag behind the current state of the environment, and estimates may suffer from sampling errors. We used stochas tic dynamic models to examine the environmental conditions that favor flexi ble rather than fixed estimates and behaviors. The examination was conducte d in the context of reproductive decisions made by the female peacock wrass e (Symphodus tinca), a nearshore Mediterranean fish. Female peacock wrasses can choose to spawn in a nest, with males that defend these nests within t erritories, or our of a nest, with males that defend neither territories no r nests. A female must expend effort and time to find nesting males, and th e profitability of this search, relative to spawning with nonnesting males, changes with the density of nests and relative hatching success of eggs in and out of nests. A female can increase her fitness by estimating the envi ronment's state and matching her reproductive decisions to the current envi ronment. These estimates can be flexible and formed by experience, or fixed and formed by selection. We found that flexible estimates based on experie nce do better when there is variance within and between seasons and when th ere is greater uncertainty. The optimal rate for forgetting experiences is set by the rate of environmental change. Comparisons of predicted female be havior using flexible and fixed estimates with observed behavior suggest th at females use estimates that are updated by experience.