Maternal stress during pregnancy affects activity, exploration and potential dispersal of daughters in an invasive fish.
Stress experienced by mothers can affect offspring phenotype, with some of these modifications potentially preparing offspring for the environment they will likely encounter. Many maternal stressors, including encounters with predators, can influence how offspring respond to risk and cues of danger later on. Using the live-bearing, highly invasive western mosquitofish, Gambusia affinis, we examined how repeated brief (<30 s) maternal exposures to a largemouth bass, Micropterus salmoides, model during pregnancy shapes offspring activity in response to cues of predation risk, as well as offspring movement through an artificial stream. Maternal predator exposure tended to increase the activity of daughters, but not sons, in a novel tank with cues of risk. In addition, maternal predator exposure increased the movement of small daughters, but not large daughters, through an artificial stream. Our results suggest that encountering predators during pregnancy can have sex-specific effects on offspring movement and exploration, particularly for sizes that are the most vulnerable to predation. In invasive species, such as mosquitofish, the transgenerational consequences of predation risk for activity, exploration and movement could help us predict potential dispersal patterns and the types of individuals at the invasion front.