Ants are a widespread group of ecologically important insects. Therefore, ants that are important predators of other ants are likely to play key roles by changing the abundance and impacts of their prey. Familiar arthropod predators, like army ants, are known for their overwhelming raids on invertebrate prey but are limited to mostly tropical systems. Thief ants (Genus: Solenopsis Westwood) are a cosmopolitan group of mostly subterranean ants found in a wide variety of ecosystem types. They are known for their extremely small sizes and their specialized predation where they stealthily tunnel into the nests of other larger ant species to capture and consume only immature ants (larvae and pupae). Predation of ant colonies by other ants, and specialized predatory behaviors of presumed top ant predators (e.g., army ants) are well known. However long-term predation effects, such as across several seasons, are still poorly understood because of a lack of experimental studies. Here we report results of a ~1.5-year press field experiment where thief ants were reduced in natural ant communities. Potential impacts, such as predator-release, were quantified by sampling the co-occurring ant community. Compared to control plots, overall worker abundance and biomass increased where thief ant were reduced, and effects varied among ant species. Results suggest predator release as select aboveground foraging increased in abundance and that thief ants may act as significant predators. Because thief ants are abundant and widespread, similar predatory effects may occur in many ant communities, and our understanding of important predators may need to adjust to include thieving species as well as army ants. Thief ants are very abundant, tiny, specialized to consume immature life stages, equipped with powerful venom, eusocial, and subterranean. This suite of adaptive traits seems unique to eusocial predators compared to animals, where "thieving" predators are usually larger in size compared to their adult-sized prey. Future work quantifying top-down regulation of prey and cascading consumptive and non-consumptive effects will help to understand thief ant predation and potential effects on ecosystem processes.

中文翻译：

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微小的地下蚂蚁是影响地上蚂蚁群落的顶级捕食者吗？

蚂蚁是一种分布广泛的生态重要昆虫。因此，作为其他蚂蚁重要捕食者的蚂蚁可能会通过改变猎物的数量和影响来发挥关键作用。熟悉的节肢动物捕食者，如军蚁，以其对无脊椎动物猎物的压倒性袭击而闻名，但仅限于热带系统。小偷蚂蚁（属：Solenopsis Westwood）是一个世界性的群体，主要分布在各种生态系统类型中。它们以极小的体型和专门的捕食而闻名，它们会悄悄地进入其他较大蚂蚁物种的巢穴，只捕捉和食用未成熟的蚂蚁（幼虫和蛹）。其他蚂蚁对蚁群的捕食以及假定的顶级蚂蚁捕食者（例如，军蚁）的专门捕食行为是众所周知的。然而，由于缺乏实验研究，人们对长期捕食效应（例如跨越几个季节）的了解仍然很少。在这里，我们报告了大约 1.5 年的新闻现场实验的结果，其中小偷蚂蚁在天然蚂蚁群落中减少了。潜在影响，例如捕食者释放，通过对共同发生的蚂蚁群落进行采样来量化。与对照地块相比，在小偷蚂蚁减少的地方，总体工人丰度和生物量增加，并且蚂蚁物种之间的影响各不相同。结果表明，随着选择的地上觅食大量增加，捕食者释放，并且小偷蚂蚁可能充当重要的捕食者。由于盗蚁数量众多且分布广泛，因此在许多蚂蚁群落中可能会出现类似的捕食效应，并且我们对重要捕食者的理解可能需要调整以包括盗贼和军蚁。小偷蚂蚁非常丰富，体积小，专门消耗未成熟的生命阶段，配备强大的毒液，真社会性和地下。与动物相比，这一套适应性特征似乎是真社会性捕食者所独有的，与动物相比，“偷窃”捕食者的体型通常比成年猎物大。未来量化猎物自上而下调节以及级联消耗性和非消耗性影响的工作将有助于了解窃贼的捕食行为以及对生态系统过程的潜在影响。与动物相比，这一套适应性特征似乎是真社会性捕食者所独有的，与动物相比，“偷窃”捕食者的体型通常比成年猎物大。未来量化猎物自上而下调节以及级联消耗性和非消耗性影响的工作将有助于了解窃贼的捕食行为以及对生态系统过程的潜在影响。与动物相比，这一套适应性特征似乎是真社会性捕食者所独有的，其中“偷窃”捕食者的体型通常比成年猎物大。未来量化猎物自上而下调节以及级联消耗性和非消耗性影响的工作将有助于了解窃贼的捕食行为以及对生态系统过程的潜在影响。