![]() Conditions favouring the persistence of local prey populations include moderate levels of predation pressure, large enough population size, the existence of sufficient genetic variation and/or phenotypic plasticity in the response to the novel predator within the population 10, 11, 12. Because of this, alien predators frequently cause more severe impacts to prey populations than native predators 8.ĭespite the initial advantage of alien predators over naïve prey, prey populations enduring predator invasions may avoid extinction by adapting to the new threat 9. However, prey are often naïve to the hunting tactics of novel predators with whom they lack a shared evolutionary past 1, 7. Native prey are usually equipped with adaptive morphologies and/or behaviours to cope with local, coexisting predators. Introduced predators can create novel ecological contexts, posing new threats to which antipredatory responses of native prey may lack adaptive value 4, 5, 6. Similar content being viewed by othersĪlien predators are considered to be one of the major threats to global biodiversity loss, causing declines and extinction of species worldwide 1, 2, 3. In contrast, populations from central Spain show lower connectivity, have been exposed to the invasive crayfish for a shorter period of time, and are more divergent in their plastic responses. ![]() We hypothesize that similar responses to the invasive crayfish in southern populations may have arisen from a combination of extended historical exposure to this introduced predator (~ 50 y) and higher levels of gene flow, as they inhabit a highly interconnected pond network. We assessed patterns of genetic variation within and among these two regions through microsatellite markers and found low genetic divergence among the southern populations but greater differentiation among the central ones. Learning abilities did not differ among southern populations, but they did among central populations. Two of the populations showed innate recognition of chemical cues from the invasive crayfish, whereas three of them learned to recognize such cues as a threat after conditioning with conspecific alarm cues. We compare the learning-mediated behavioural responses of tadpoles from six populations across two regions in Spain (central and southern), with different histories of exposure to the presence of the invasive species. Here we examine geographical variation in the learning ability of larval spadefoot toads ( Pelobates cultripes) to recognize invasive predatory crayfish ( Procambarus clarkii). However, phenotypic plasticity and learned predator recognition may help prey populations to survive novel predators. ![]() Alien predators are a major cause of decline and extinction of species worldwide, since native organisms are rarely equipped with specific antipredatory strategies to cope with them.
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