Selective defecation and selective foraging: Antiparasite behavior in wild ungulates?
Selective defecation and selective foraging: Antiparasite behavior in wild ungulates?
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DOI：
10.1111/j.1439-0310.2004.01013.x
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发表时间：
2004-11-01
期刊：
影响因子：
1.7
通讯作者：
Ezenwa, VO
中科院分区：
文献类型：
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作者：
Ezenwa, VO
选择性排便和选择性觅食是放牧有蹄类动物用来减少粪-口传播寄生虫感染的两种潜在的抗寄生虫行为。虽然有一些证据表明，国内的物种使用这些策略，少有人知道这些行为在野生有蹄类动物的发生和效力。在这项研究中，我研究了野生羚羊是否使用选择性排便和选择性觅食策略，以减少暴露于胃肠道线虫寄生虫。通过定量的寄生虫水平在环境中的排便模式的三个物种，迪克迪克（Madoqua kirkii），格兰特的瞪羚（Gazella granti），和黑斑羚（Aepyceros melampus），我发现，线虫幼虫的浓度在牧场附近的集群粪便（粪坑）相比，单个粪便颗粒组或无粪便的地区。此外，在自由放养的Dik-Dik中进行的实验性喂养试验表明，个体选择性地避免在粪便浓度附近喂养。鉴于在粪便群附近发现寄生虫污染增加，避免粪便有助于减少宿主对寄生虫的消耗，因此可能是某些物种的有效抗寄生虫行为。另一方面，虽然寄生虫幼虫的浓度在附近的粪坑加上主机避免这些地区在放牧过程中可能会减少主机接触寄生虫，结果显示在一个栖息地的粪坑和幼虫丰度在控制网站之间的正相关关系表明，粪坑可能会增加，而不是减少整体主机接触寄生虫。如果是这样的话，粪坑的形成可能不是一个可行的抗寄生虫策略。
Selective defecation and selective foraging are two potential antiparasite behaviors used by grazing ungulates to reduce infection by fecal-oral transmitted parasites. While there is some evidence that domestic species use these strategies, less is known about the occurrence and efficacy of these behaviors in wild ungulates. In this study, I examined whether wild antelope use selective defecation and selective foraging strategies to reduce exposure to gastrointestinal nematode parasites. By quantifying parasite levels in the environment in relation to the defecation patterns of three species, dik-dik (Madoqua kirkii), Grant's gazelle (Gazella granti), and impala (Aepyceros melampus), I found that nematode larval concentrations in pasture were higher in the vicinity of clusters of feces (dung middens) compared to single fecal pellet groups or dung-free areas. In addition, experimental feeding trials in free-ranging dik-dik showed that individuals selectively avoided feeding near concentrations of feces. Given that increased parasite contamination was found in the immediate vicinity of fecal clusters, fecal avoidance could help reduce host consumption of parasites and may therefore be an effective antiparasite behavior for certain species. On the other hand, while the concentration of parasite larvae in the vicinity of middens coupled with host avoidance of these areas during grazing could reduce host contact with parasites, results showing a positive correlation between the number of middens in a habitat and larval abundance at control sites suggest that dung middens might increase and not decrease overall host exposure to parasites. If this is the case, dung midden formation may not be a viable antiparasite strategy.