Data from: Is the enhanced dispersal rate seen at invasion fronts a behaviourally plastic response to encountering novel ecological conditions?

As a population expands into novel areas (as occurs in biological invasions), the range edge becomes dominated by rapidly dispersing individuals—thereby accelerating the rate of population spread. That acceleration has been attributed to evolutionary processes (natural selection and spatial sorting), to which we add a third complementary process: behavioural plasticity. Encountering environmental novelty may directly elicit an increased rate of dispersal. When we reciprocally translocated cane toads (Rhinella marina) among study sites in southern Australia, the transported animals massively increased dispersal rates relative to residents (to an extent similar to the evolved increase between range-core versus invasion-front toad populations in Australia). The responses of these translocated toads show that even range-core toads are capable of the long-distance dispersal rates of invasion-front conspecifics and suggest that rapid dispersal (rather than evolving de novo) has simply been expanded from facultative to constitutive expression.

当种群向全新区域扩张时（正如生物入侵过程中所发生的情形），种群分布范围的边缘会被快速扩散的个体所主导，进而加速种群的扩散速率。此前，这种扩散速率的加速现象被归因于两类进化过程——自然选择（natural selection）与空间分选（spatial sorting），而我们在此补充第三种互补的过程：行为可塑性（behavioural plasticity）。遭遇全新环境可能会直接诱发个体扩散速率的提升。我们在澳大利亚南部的多个研究样地之间对蔗蟾（Rhinella marina）开展相互移植实验时发现，被移植的个体相较于本地居留个体，其扩散速率出现了大幅提升，其提升幅度与澳大利亚本土分布范围核心区种群与入侵前沿种群之间因进化产生的扩散速率提升幅度相当。这些被移植蔗蟾的反应表明，即便分布范围核心区的蔗蟾，也具备入侵前沿同种个体所拥有的长距离扩散能力；同时该结果也提示，快速扩散能力并非从头进化而来，而只是从兼性表达转变为组成型表达。