Population‐level variation in infection outcomes not influenced by pesticide exposure in larval wood frogs ( Rana sylvatica )
Population‐level variation in infection outcomes not influenced by pesticide exposure in larval wood frogs ( Rana sylvatica )
复制标题
林蛙幼虫（Rana sylvatica）感染结果的种群水平变化不受农药暴露的影响
DOI：
10.1111/fwb.13708
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发表时间：
2021
影响因子：
2.7
通讯作者：
Hoverman, Jason T.
中科院分区：
文献类型：
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作者：
Billet, Logan S.;Wuerthner, Vanessa P.;Hua, Jessica;Relyea, Rick A.;Hoverman, Jason T.
越来越多的证据表明，非目标野生动物物种的种群可以进化出对农药的耐受性。随着全球生态系统越来越多地暴露于化学污染物，重要的是不仅要考虑污染物暴露的直接后果，而且要考虑与进化反应相关的潜在成本。理论预测可能存在权衡，包括对寄生虫的易感性增加，与进化的农药耐受性相关。然而，目前还不清楚环境背景（即在当代环境中存在/不存在农药）如何与进化的农药耐受水平相互作用，以影响感染outcomes.Several研究表明，林蛙（林蛙sylvatica）人口接近农业，经常暴露于农药是更有可能的，表现出更高的基线耐受农药比人口远离农业。使用八个林蛙种群从整个农业梯度，我们探讨了与人口的接近农业（农药耐受性的代理），以及如何影响这些模式的实验暴露的蝌蚪杀虫剂西维因的易感性寄生虫的变化模式。我们首先将蝌蚪置于含有农药西维因（1 mg/L）的环境或无农药对照环境中5天，然后将蝌蚪暴露于吸虫（Echinostoma trivolvis）或蛙病毒（蛙病毒3）。我们发现吸虫易感性的变化与蝌蚪种群接近农业有关。来自靠近农业的人群的个体比来自远离农业的人群的个体更容易感染吸虫。蛙病毒的易感性与接近农业无关。令人惊讶的是，暴露于西维因增加了感染蛙病毒的蝌蚪的存活率。西维因暴露对测量的疾病结果没有其他显著影响。这项研究为吸虫抗性和假定的农药耐受性之间的潜在权衡提供了证据。我们发现，宿主种群对病原体的易感性可能存在显着差异，但农药暴露并不总是增加寄生虫的易感性或统一加剧疾病的后果。需要进一步的研究来确定种群间的遗传变异如何影响对寄生虫的易感性，以及这些易感性模式在空间和时间上是否一致。
There is increasing evidence that populations of non‐target wildlife species can evolve tolerance to pesticides. As ecosystems become increasingly exposed to chemical contaminants globally, it is important to consider not only the immediate consequences of contaminant exposure but also the potential costs associated with evolved responses. Theory predicts there may be trade‐offs, including increased susceptibility to parasites, associated with evolved pesticide tolerance. It remains unclear, however, how environmental context (i.e. presence/absence of pesticides in the contemporary environment) interacts with evolved pesticide tolerance levels to influence infection outcomes.Several studies have demonstrated that wood frog (Rana sylvatica) populations close to agriculture, where frequent exposure to pesticides is more likely, show higher baseline tolerance to pesticides than do populations far from agriculture. Using eight wood frog populations from across an agricultural gradient, we explored patterns of variation in susceptibility to parasites associated with a population's proximity to agriculture (a proxy for pesticide tolerance), and how these patterns are influenced by experimental exposure of tadpoles to the insecticide carbaryl. We did this by first placing tadpoles in an environment containing the pesticide carbaryl (1 mg/L) or in a pesticide‐free control environment for 5 days, and subsequently exposing tadpoles to trematodes (Echinostoma trivolvis) or ranavirus (frog virus 3).We found that variation in trematode susceptibility was related to the tadpole populations’ proximity to agriculture. Individuals from populations located close to agriculture were modestly more susceptible to trematode infections than individuals from populations farther from agriculture. Ranavirus susceptibility was not associated with proximity to agriculture.Surprisingly, exposure to carbaryl increased the survival rates of tadpoles infected with ranavirus. There were no other significant effects of carbaryl exposure on the measured disease outcomes.This study provides evidence for a potential trade‐off between trematode resistance and putative pesticide tolerance. We show that host populations can vary significantly in their susceptibility to pathogens, but that pesticide exposure does not always increase parasite susceptibility or uniformly exacerbate disease outcomes. Further research is needed to determine how genetic variation among populations impact susceptibility to parasites, and if these patterns of susceptibility are consistent across space and time.