Invasive species have major impacts on biodiversity and are one of the primary causes of amphibian decline and extinction. Unlike other top ant invaders that negatively affect larger fauna via chemical defensive compounds, the Argentine ant (Linepithema humile) does not have a functional sting. Nonetheless, it deploys defensive compounds against competitors and adversaries. We estimated levels of ant aggression toward 3 native terrestrial amphibians by challenging juveniles in field ant trails and in lab ant foraging arenas. We measured the composition and quantities of toxin in L. humile by analyzing pygidial glands and whole-body contents. We examined the mechanisms of toxicity in juvenile amphibians by quantifying the toxin in amphibian tissues, searching for histological damages, and calculating toxic doses for each amphibian species. To determine the potential scope of the threat to amphibians, we used global databases to estimate the number, ranges, and conservation status of terrestrial amphibian species with ranges that overlap those of L. humile. Juvenile amphibians co-occurring spatially and temporally with L. humile die when they encounter L. humile on an ant trail. In the lab, when a juvenile amphibian came in contact with L. humile the ants reacted quickly to spray pygidial-gland venom onto the juveniles. Iridomyrmecin was the toxic compound in the spray. Following absorption, it accumulated in brain, kidney, and liver tissue. Toxic dose for amphibian was species dependent. Worldwide, an estimated 817 terrestrial amphibian species overlap in range with L. humile, and 6.2% of them are classified as threatened. Our findings highlight the high potential of L. humile venom to negatively affect amphibian juveniles and provide a basis for exploring the largely overlooked impacts this ant has in its wide invasive range.

中文翻译：

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阿根廷蚁毒对陆生两栖动物的影响

入侵物种对生物多样性有重大影响，是导致两栖动物数量减少和灭绝的主要原因之一。与通过化学防御化合物对大型动物群产生负面影响的其他顶级蚂蚁入侵者不同，阿根廷蚂蚁（Linepithema humile）没有功能性刺痛。尽管如此，它还是针对竞争对手和对手部署了防御性化合物。我们通过在野外蚂蚁小径和实验室蚂蚁觅食场所挑战幼虫来估计蚂蚁对 3 种本地陆生两栖动物的攻击程度。我们通过分析尾腺和全身内容物测量了 L. humile 中毒素的成分和数量。我们通过量化两栖动物组织中的毒素、寻找组织学损伤并计算每种两栖动物物种的毒性剂量，研究了幼年两栖动物的毒性机制。为了确定两栖动物面临的潜在威胁范​​围，我们使用全球数据库来估计陆地两栖动物物种的数量、范围和保护状况，其范围与 L. humile 的范围重叠。与 L. humile 在空间和时间上同时发生的幼年两栖动物在蚂蚁踪迹上遇到 L. humile 时会死亡。在实验室里，当一只幼年两栖动物与 L. humile 接触时，蚂蚁会迅速做出反应，将尾腺毒液喷到幼虫身上。Iridomyrmecin 是喷雾中的有毒化合物。吸收后，它在脑、肾和肝组织中积累。两栖动物的毒性剂量是物种依赖性的。在世界范围内，估计有 817 种陆生两栖动物与 L. humile 的分布范围重叠，其中 6.2% 被列为受威胁物种。我们的研究结果突出了 L.