While the Galápagos Archipelago is known for its endemic flora and fauna, many introduced species have also become naturalised there, especially on the human-inhabited islands. The only amphibian species known to have established on the islands, the Fowler’s snouted treefrog (Scinax quinquefasciatus), is thought to have arrived about two decades ago. Since then, this treefrog has substantially extended its range to the islands of Santa Cruz and Isabela. Our study explores the potential influence of this introduced amphibian on native trophic systems on Santa Cruz and identifies potential antagonists likely to control larval frog populations. To understand the impact of S. quinquefasciatus as a predator of local invertebrate fauna, we performed a stomach-content analysis of 228 preserved adult specimens from seven different localities on Santa Cruz. Of the 11 macroinvertebrate orders recorded, Lepidoptera constituted more than 60% of the contents. We also identified active predators of S. quinquefasciatus tadpoles: larvae of the endemic diving beetle (Thermonectus basillarus galapagoensis). To determine the efficiency of this predator, we conducted predator-prey experiments in ex situ conditions. Tadpole predation was highest after first exposure to the predator and significantly decreased over time. Our experimental results demonstrate that although T. b. galapagoensis larvae are effective tadpole predators, their feeding saturation rates are likely inadequate for frog population control. Our findings provide the first baseline data necessary to make informed ecological impact assessments and monitoring schemes on Santa Cruz for this introduced treefrog.

中文翻译：

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食用与被食用：加拉帕戈斯群岛人为环境中引入的蛙金丝雀（Scinax quinquefasciatus）的营养相互作用

尽管加拉帕戈斯群岛以其特有的动植物群而闻名，但许多引进的物种也已在那里归化，特别是在人类居住的岛屿上。福勒的鼻子树蛙（Scinax quinquefasciatus）是岛上唯一已知的两栖动物，大约在二十年前就已经到达。从那时起，这只树蛙就将其范围大大扩展到了圣克鲁斯和伊莎贝拉岛。我们的研究探索了这种引入的两栖动物对圣克鲁斯天然营养系统的潜在影响，并确定了可能控制幼虫蛙类种群的潜在拮抗剂。为了了解作为当地无脊椎动物动物捕食者的金黄色葡萄球菌的影响，我们对圣克鲁斯（Santa Cruz）七个地区的228个保存完好的成年标本进行了胃内容物分析。在记录的11个大型无脊椎动物订单中，鳞翅目占内容的60％以上。我们还确定了活跃的捕食者的S. quinquefasciatus t：地方性潜水甲虫（Thermonectus basillarus galapagoensis）的幼虫。为了确定这种捕食者的效率，我们在异地条件下进行了捕食者-猎物实验。first第一次接触食肉动物后，食肉pre的捕食率最高，并且随时间推移而显着下降。我们的实验结果表明，尽管T。galapagoensis幼虫是有效的t捕食者，它们的摄食饱和率可能不足以控制青蛙的种群。我们的研究结果提供了必要的第一批基线数据，以便对这种引入的树蛙进行明智的生态影响评估和监测方案。