Consistent Behavioral Syndrome Across Seasons in an Invasive Freshwater Fish

Understanding the linkage between behavioral types and dispersal tendency has become a pressing issue in light of global change biological invasions. Here, we explore whether dispersing individuals exhibit that differ from those remaining source population. We investigated feral population guppies ( Poecilia reticulata ) undergoes yearly range shift cycle. Guppies are among most widespread invasive species world, but temperate regions these tropical fish can only survive winter-warm freshwaters. Established thermally-altered stream Germany, confined to warm-water influx winter, spread peripheral parts as thermally accessible. sampled winter-abandoned site March, June August. Fish were tested for boldness, sociability activity involving open-field tests including interactions with robotic social partner. differed consistently each other all three traits within sample. Average trait expression across seasons, however, could not detect differences downstream Instead, populations exhibited remarkably stable syndrome boldness despite strong seasonal changes water temperature associated environmental factors. conclude random drift (opposed personality-biased dispersal) is more likely mode guppies, at least stream. In face fluctuating environments, seem be extremely effective keeping expressions constant, which help explain their successful invasion adaptation new disturbed habitats.