Wall R, Beynon S
Veterinary Parasitology and Ecology Group, School of Biological Sciences, University of Bristol, Bristol, U.K.
Med Vet Entomol. 2012 Mar;26(1):1-8. doi: 10.1111/j.1365-2915.2011.00984.x. Epub 2011 Oct 19.
Following the treatment of cattle with veterinary parasiticides and insecticides, residues are excreted into the dung in concentrations that may be toxic to functionally important dung-colonizing insects. In the dung, these residues cause a range of well-studied lethal and sub-lethal effects, the magnitudes of which vary with the compound used, mode of administration and concentration, and the insect species in question. Particular concern has been associated with the use of macrocyclic lactones in this context. Loss of insect colonizers may delay pat decomposition, but field studies report contrasting results that reflect confounding factors such as weather conditions, pat moisture content, pat location, time of year and dung insect species phenologies. The question of fundamental concern is whether the impacts seen in experimental or laboratory studies are likely to have a functional impact on insect populations, community interactions and the economically important process of dung decomposition. Recent studies which have attempted to address these wider, landscape-level impacts in temperate ecosystems are reviewed here. These show that the extent to which chemical residues may have any sustained ecological impact will depend on both a range of farm management factors, such as the temporal and spatial patterns of chemical use, the number of animals treated and the choice of active ingredient, and a range of insect-related factors, such as abundance, population dynamics and dispersal rates. However, they also demonstrate that considerable uncertainty remains about the likely extent of such effects and that current data are insufficient to support firm conclusions regarding sustained pasture-level effects. More large-scale, longterm field experiments are required, particularly in relation to insect dispersal and functional interactions within the dung insect community.
在用兽用杀寄生虫剂和杀虫剂治疗牛之后，残留物会以可能对在粪便中定殖的功能重要昆虫有毒的浓度排泄到粪便中。在粪便中，这些残留物会产生一系列经过充分研究的致死和亚致死效应，其严重程度因所使用的化合物、给药方式和浓度以及所涉及的昆虫种类而异。在这种情况下，大环内酯类药物的使用尤其令人担忧。昆虫定殖者的减少可能会延迟粪便分解，但实地研究报告的结果相互矛盾，这反映了天气条件、粪便湿度、粪便位置、一年中的时间以及粪便昆虫种类物候等混杂因素。最根本的问题是，在实验或实验室研究中观察到的影响是否可能对昆虫种群、群落相互作用以及具有经济重要性的粪便分解过程产生功能性影响。本文综述了最近试图解决温带生态系统中这些更广泛的景观层面影响的研究。这些研究表明，化学残留物可能产生任何持续生态影响的程度将取决于一系列农场管理因素，如化学物质使用的时间和空间模式、接受治疗的动物数量以及活性成分的选择，以及一系列与昆虫相关的因素，如丰度、种群动态和扩散率。然而，它们也表明，关于此类影响的可能程度仍存在相当大的不确定性，而且目前的数据不足以支持就牧场层面的持续影响得出确凿结论。需要进行更多大规模、长期的实地实验，特别是关于粪便昆虫群落内昆虫扩散和功能相互作用的实验。
