Campero Melina, Slos Stefanie, Ollevier Frans, Stoks Robby
Katholieke Universiteit Leuven (KULeuven), Laboratory of Aquatic Ecology, Ch. Deberiotstraat 32, B-3000, Leuven, Belgium.
Ecol Appl. 2007 Oct;17(7):2111-22. doi: 10.1890/07-0442.1.
Despite their relevance for risk assessment, the interactive effects of pesticide and predation cues are poorly understood because the underlying behavioral and physiological mechanisms are largely unknown. To explore these mechanisms, we reared larvae of the damselfly Coenagrion puella at three different predation risk levels and a range of environmentally realistic concentrations of three pesticides used worldwide (atrazine, carbaryl, and endosulfan). We compared key development responses (growth rate, developmental time, and final size) against food ingestion, assimilation, and conversion efficiency, and acetylcholinesterase (AChE) activity. Predation risk impaired all endpoints, including AChE activity, while the effects of pesticide stress were smaller for atrazine and endosulfan and absent for carbaryl. The effects of both stressors and their interaction on life history were mostly indirect through resource acquisition and energy allocation. Compensatory physiological mechanisms to pesticide stress (atrazine and endosulfan) were present in larvae reared in the absence of predation stress but were offset under predation stress. As a result, smaller size (atrazine and endosulfan) and lower growth rate (endosulfan) from pesticide stress were only found in the highest predation risk treatment. Our results provide insight as to the conditions under which interactions between stressors are likely to occur: damselfly populations at high density and living in fish ponds will be more affected by pesticides than populations at low densities in fishless ponds. By identifying variables that may shape the interaction between predation stress and other stressors such as pesticides, our mechanistic approach may help to bridge the gap between laboratory and field studies.
尽管农药和捕食线索的交互作用与风险评估相关，但由于其潜在的行为和生理机制大多未知，所以人们对其了解甚少。为了探究这些机制，我们在三种不同的捕食风险水平以及全球范围内使用的三种农药（阿特拉津、西维因和硫丹）的一系列环境现实浓度下饲养豆娘（Coenagrion puella）的幼虫。我们将关键发育反应（生长速率、发育时间和最终大小）与食物摄入、同化和转化效率以及乙酰胆碱酯酶（AChE）活性进行了比较。捕食风险损害了所有指标，包括AChE活性，而阿特拉津和硫丹的农药胁迫影响较小，西维因则无影响。两种胁迫因素及其对生活史的相互作用大多是通过资源获取和能量分配间接产生的。在没有捕食胁迫的情况下饲养的幼虫中存在对农药胁迫（阿特拉津和硫丹）的补偿性生理机制，但在捕食胁迫下会被抵消。因此，仅在最高捕食风险处理中发现了农药胁迫导致的较小体型（阿特拉津和硫丹）和较低生长速率（硫丹）。我们的研究结果揭示了胁迫因素之间可能发生相互作用的条件：高密度且生活在鱼塘中的豆娘种群比低密度且生活在无鱼池塘中的种群更容易受到农药的影响。通过识别可能影响捕食胁迫与其他胁迫因素（如农药）之间相互作用的变量，我们的机制方法可能有助于弥合实验室研究和实地研究之间的差距。
