Ecological immunization: In situ training of free-ranging predatory lizards reduces their vulnerability to invasive toxic prey

In Australia, large native predators are fatally poisoned when they ingest invasive cane toads (Rhinella marina). As a result, the spread of cane toads has caused catastrophic population declines in these predators. Immediately prior to the arrival of toads at a floodplain in the Kimberley region, we induced conditioned taste aversion in free-ranging varanid lizards (Varanus panoptes), by offering them small cane toads. By the end of the 18-month study, only one of 31 untrained lizards had survived longer than 110 days, compared to more than half (nine of 16) of trained lizards; the maximum known survival of a trained lizard in the presence of toads was 482 days. In situ aversion training (releasing small toads in advance of the main invasion front) offers a logistically simple and feasible way to buffer the impact of invasive toads on apex predators.

在澳大利亚，大型本土捕食者误食入侵性海蟾蜍（Rhinella marina）后会中毒身亡。因此，海蟾蜍的扩散已导致这些捕食者的种群出现灾难性下降。在海蟾蜍抵达金伯利地区某洪泛平原的前夕，我们通过向自由活动的巨蜥（Varanus panoptes）投喂小型海蟾蜍，诱导其产生条件性味觉厌恶。在为期18个月的研究结束时，31只未经过训练的巨蜥中仅1只存活时长超过110天；而16只经过训练的巨蜥中存活超110天的个体占比超过一半（9只），且已知训练后的巨蜥在海蟾蜍存在的环境中最长存活时长可达482天。原位厌恶训练（即在主要入侵前沿提前投放小型海蟾蜍）为缓解入侵性海蟾蜍对顶级捕食者的影响提供了一种操作简便且切实可行的方案。