Constructing an invasion machine: the rapid evolution of a dispersal-enhancing phenotype during the cane toad invasion of Australia

Biological invasions can induce rapid evolutionary change. As cane toads (Rhinella marina) have spread across tropical Australia over an 80-year period, their rate of invasion has increased from around 15 to 60 km per annum. Toads at the invasion front disperse much faster and further than conspecifics from range-core areas, and their offspring inherit that rapid dispersal rate. We investigated morphological changes that have accompanied this dramatic acceleration, by conducting three-dimensional morphometric analyses of toads from both range-core and invasion-front populations. Morphology of heads, limbs, pectoral girdles and pelvic girdles differed significantly between toads from the two areas, ranging from 0.5% to 16.5% difference in mean bone dimensions between populations, with invasion-front toads exhibiting wider forelimbs, narrower hindlimbs and more compact skulls. Those changes plausibly reflect an increased reliance on bounding (multiple short hops in quick succession) rathe...生物入侵可引发快速的进化改变。在80余年的时间跨度内，蔗蟾（Rhinella marina）已扩散至澳大利亚热带区域，其入侵速率从每年约15公里提升至60公里。入侵前沿种群的蔗蟾相较于分布核心区的同种个体，扩散速度更快、扩散距离更远，且其后代会继承这种快速扩散的性状。我们针对这场剧烈扩散伴随的形态学变化展开研究，对分布核心区与入侵前沿种群的蔗蟾开展了三维形态计量分析。两类种群的蔗蟾在头部、四肢、肩带及骨盆带的形态上均存在显著差异，种群间平均骨骼尺寸的差异幅度介于0.5%至16.5%之间；入侵前沿的蔗蟾表现出更宽阔的前肢、更狭窄的后肢以及更紧凑的头骨。上述变化合理地反映出，这些蔗蟾愈发依赖于跳跃式移动（即连续快速的多次短距离跳跃），而非……