Laboratory of Aquatic Ecology and Evolutionary Biology, University of Leuven, Deberiotstraat 32, B-3000 Leuven, Belgium.
Aquat Toxicol. 2012 Apr;110-111:91-8. doi: 10.1016/j.aquatox.2011.12.019. Epub 2012 Jan 2.
An increasing number of studies have documented that sublethal pesticide exposure can change predator-prey interactions. Most of these studies have focused on effects of long-term pesticide exposure on only one type of antipredator traits and have not directly linked changes in these traits to mortality by predation. To get a better mechanistic understanding of how short-term pesticide pulses make prey organisms more vulnerable to predation, we studied effects of 24h exposure to a sublethal concentration of the insecticide endosulfan and the herbicide Roundup on the major antipredator traits and the resulting mortality by predation in larvae of the damselfly Enallagma cyathigerum. A pulse of both pesticides affected antipredator traits involved in avoiding detection by predators as well as traits involved in escape after detection. After a pesticide pulse, larvae increased activity levels and even further increased the number of walks when predation risk was present. Further, an endosulfan pulse tended to reduce escape swimming speed. In contrast, previous exposure to Roundup caused the larvae to swim faster, yet less often when attacked. Importantly, although both studied pesticides induced maladaptive changes in overall activity, only for endosulfan this resulted in an increased mortality by predation. Our study highlights that considering changed predator-prey interactions may improve ecological risk evaluations of short pesticide pulses, yet also underscores the need (1) to consider effects on all important antipredator traits of the prey as trait compensation may occur and (2) to effectively score the outcome of predator-prey interactions in staged encounters.
越来越多的研究记录表明，亚致死浓度的农药暴露会改变捕食者-猎物相互作用。这些研究大多集中在长期暴露于一种农药对一种抗捕食者特征的影响上，并没有直接将这些特征的变化与捕食导致的死亡率联系起来。为了更好地了解短期农药脉冲如何使猎物更容易受到捕食，我们研究了 24 小时暴露于亚致死浓度的杀虫剂硫丹和除草剂 Roundup 对豆娘幼虫主要抗捕食者特征的影响，以及这些特征对捕食的死亡率的影响。这两种农药的脉冲都会影响到躲避捕食者的探测的抗捕食者特征，以及在被探测到后的逃避特征。在农药脉冲之后，幼虫增加了活动水平，在存在捕食风险时甚至会增加行走的次数。此外，硫丹脉冲往往会降低逃避游泳速度。相比之下，之前接触过草甘膦会使幼虫在受到攻击时游得更快，但次数却更少。重要的是，尽管两种研究的农药都会导致整体活动的适应性变化，但只有硫丹会导致捕食导致的死亡率增加。我们的研究强调，考虑到改变的捕食者-猎物相互作用可能会改善对短期农药脉冲的生态风险评估，但也强调需要（1）考虑猎物所有重要的抗捕食者特征的影响，因为可能会出现特征补偿，以及（2）在分阶段遭遇中有效地评分捕食者-猎物相互作用的结果。
