Behavioural adaptations to biological invasions

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Interspecific competition has shaped animal and plant communities, and the evolution of species. Invasive species have stepped outside their co-evolutionary networks, and allow the study of direct, interspecific competition at the invasion range. Unplanned translocations and introductions of wild animals are nowadays common due to the global mobility of goods and people. They remain undetected, if the introduced individuals melt into existing populations of the same species, or if the introduced species is not able to establish at the terra nova. Here I aim to study behavioural traits and behavioural flexibility which may contribute to the invasive potential of a species, and behavioural traits and adaptation of the invaded community, which may also determine establishment success of an introduced species. A century ago bank voles Myodes glareolus were accidentally introduced to vole-free Ireland. After the last ice-age actually very few mammal species reached the Ireland and the only other free-ranging small rodent is the wood mouse Apodemus sylvaticus, also introduced many centuries ago. While in Central Europe the species are sympatric, the wood mice experienced competitive release over many centuries, which may have changed the species. The vole population quickly expanded and currently covers about 2/3 of Ireland, so that both species nowadays compete for scarce woodland and hedge habitats, and the addition of bank voles decreases local wood mouse densities. This simple rodent community offers a unique opportunity to study, in a first step, two questions: (1) Can invading rodent species adjust their behaviour while expanding into new areas? I expect more exploitative and mobile animals at the expansion edge, compared to animals at established ranges. (2) Do invaded animal communities adjust behaviourally in response to cohabitation with a novel competitor? I expect that due to classical ecological theory of competition behavioural characters of wood mice displace to avoid competition and will investigate animal personality, diet, and activity patterns. However, novel results suggest that for ecological very similar species ecological niches may be individual, based on animal personality and space use, which will be also considered for this species pair. For these questions I will use methods established to quantify animal personality of small rodents, i.e. individual, behavioural traits that are repeatable across time and contexts, isotope analysis, and investigate activity patterns. Specifically, behavioural studies will complement earlier genetic and parasitological studies on the vole-mice community in Ireland. More general, my results will expand on our knowledge of the role of behaviour in invasion biology, and thus broaden our conceptual understanding of the mechanisms of interspecific competition.