Data from: Dung beetles reduce livestock gastrointestinal parasite availability on pasture

Anthelmintics are widely used to control gastrointestinal parasites of livestock. However, the residues of these compounds, particularly the macrocyclic lactones, are excreted largely unmetabolised in faeces, where they may have toxic effects on dung-colonising insects. Impoverishment of the coprophagous beetle community impairs the process of dung recycling and, as a result, may enhance the persistence of dung-dwelling helminth parasitic stages. To test this possibility, a large-scale field trial was conducted in south-west England. The availability of infective parasite helminth larvae (L3) was investigated on the herbage around 240 artificial 1 kg dung pats that had been constructed from the faeces of beef cattle with naturally acquired strongyle infections. Herbage up to 15 cm surrounding each pat was sampled at 2, 4, 6, 8 and 10 weeks after deposition. Pats were subject to enhanced, natural or no dung beetle colonisation and uncontrolled or enhanced rainfall. Under uncontrolled rainfall conditions, 2 weeks after pat deposition, significantly more L3 were recovered from around pats that were exposed to beetle colonisation than from pats that were not colonised. However, by week 8, significantly fewer L3 were recovered from around pats that were exposed to beetle colonisation compared to uncolonised pats. Under conditions of enhanced rainfall, pats yielded significantly more L3 than under uncontrolled rainfall conditions, and there were no differences in recovery from herbage around pats with enhanced, natural, or no beetle colonisation.
The data suggest that over the duration of a summer grazing season, temperate habitat dung colonizing insect communities, which include mainly small endocoprid dung beetles of the genus Aphodius, can reduce the development and survival of livestock gastrointestinal parasites on pastures, but that this can be overridden by the effect of high rainfall. Synthesis and applications. The work demonstrates that conservation of dung beetle populations in temperate climates is important in livestock management, not only for their essential role in dung degradation and nutrient cycling, but because their activity can also reduce the survival and availability of gastrointestinal parasites on pastures.

驱虫药（anthelmintics）被广泛用于防控畜禽的胃肠道寄生虫。然而，这类化合物的残留（尤其是大环内酯类（macrocyclic lactones））大多以原形经粪便排出，这些残留可对粪便栖息昆虫产生毒性作用。食粪甲虫群落的衰退会削弱粪便降解循环过程，进而可能延长粪便栖息蠕虫寄生阶段的存活时间。为验证这一假设，研究团队在英格兰西南部开展了一项大规模田间试验。

试验以240份取自自然感染圆线虫（strongyle）的肉牛粪便制备的1公斤重人工粪块为研究对象，探究了每份粪块周边15厘米范围内的牧草上，感染性蠕虫幼虫（L3）的可获得性。在粪块放置后的第2、4、6、8和10周，对每块粪块周边15厘米内的牧草进行采样。试验设置了三种粪便甲虫定植水平：强化定植、自然定植和无定植，同时设置自然降雨与强化降雨两种降水条件。

在自然降雨条件下，粪块放置2周后，经甲虫定植的粪块周边牧草中回收的L3幼虫数量显著高于未定植粪块；但至第8周时，经甲虫定植的粪块周边牧草回收的L3幼虫数量则显著低于未定植粪块。在强化降雨条件下，所有粪块周边牧草回收的L3幼虫数量均显著高于自然降雨条件，且不同甲虫定植水平的粪块之间L3回收量无显著差异。

研究数据表明，在整个夏季放牧季期间，温带生境中的粪便栖息昆虫群落（主要包含蜉金龟属（Aphodius）的小型内栖粪食甲虫）可降低牧场中畜禽胃肠道寄生虫的发育与存活能力，但该效应可被强降雨的作用抵消。

综合与应用：本研究证实，在温带气候区保护粪食甲虫种群对畜禽养殖具有重要意义——这不仅因为甲虫在粪便降解与养分循环中发挥着关键作用，还因为其活动可降低牧场中胃肠道寄生虫的存活能力与传播风险。