Animal Ecology, Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden; Department of Life Sciences, University of Trieste, Trieste, Italy.
Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Ecotoxicol Environ Saf. 2017 Oct;144:107-114. doi: 10.1016/j.ecoenv.2017.06.014. Epub 2017 Jun 9.
Damselflies form an essential part of the aquatic and terrestrial food web. Pesticides may, however, negatively affect their behavior, physiology, and survival. To assess this, a 42-day-lasting bioassay was conducted, during which damselfly larvae (Ischnura graellsii; n = 20) were repeatedly exposed to lambda-cyhalothrin (3 days at; 0, 10, 50, 250, 1250, and 6250ng LCH L), followed by recovery phases (4 days) in pesticide-free medium for six weeks. This exposure design was used to simulate frequent runoff events in the field. Variables related to the behavior (strikes against prey and capture success), growth, physiology (lipid content and fatty acid composition), as well as mortality were assessed throughout the experiment. The two highest LCH concentrations induced 100% mortality within the first 48h, whereas 85% of the test organisms survived 28 days under control conditions. The number of strikes against prey was not affected by LCH. In contrast, prey capture success decreased significantly (up to ~50% at 250ng LCH L, for instance, after the third pulse exposure) following LCH-exposures compared to the control. This difference was not observed after recovery phases, however, which did not counteract the enhanced energy demand for detoxification and defense mechanisms indicated by a lower growth rate (up to ~20%) and lipid content (up to ~30%) of damselflies at 50 and 250ng LCH L. In addition, two essential fatty acids (eicosapentaenoic acid and arachidonic acid) and two precursors (linolenic acid and α-linolenic acid) decreased in their concentrations upon exposure towards 250ng LCH L. Thus the results of this study indicate that long-term exposure towards LCH pulses can affect damselfly behavior, physiology and survival. Given the essential role of damselflies in food web dynamics, these effects may potentially translate into local population impairments with subsequent bottom-up directed effects within and across ecosystem boundaries.
豆娘是水生和陆地食物网的重要组成部分。然而，杀虫剂可能会对它们的行为、生理和生存产生负面影响。为了评估这一点，进行了为期 42 天的生物测定，在此期间，反复将豆娘幼虫（Ischnura graellsii；n = 20）暴露于 lambda-氯氰菊酯（3 天；0、10、50、250、1250 和 6250ng LCH L），然后在无农药的培养基中进行 6 周的恢复期。这种暴露设计用于模拟田间频繁的径流事件。在整个实验过程中，评估了与行为（攻击猎物和捕获成功率）、生长、生理（脂质含量和脂肪酸组成）以及死亡率相关的变量。前两个最高的 LCH 浓度在头 48 小时内导致 100%的死亡率，而在对照条件下，85%的测试生物在 28 天内存活。LCH 没有影响攻击猎物的次数。相比之下，与对照相比，在 LCH 暴露后，猎物的捕获成功率显著下降（例如，在第三次脉冲暴露后下降了50%）。然而，在恢复期后没有观察到这种差异，这并没有抵消由于解毒和防御机制的增强而导致的能量需求增加，这表现为在 50 和 250ng LCH L 时豆娘的生长速度（高达20%）和脂质含量（高达~30%）降低。此外，两种必需脂肪酸（二十碳五烯酸和花生四烯酸）和两种前体（亚麻酸和α-亚麻酸）在暴露于 250ng LCH L 时浓度降低。因此，这项研究的结果表明，长期暴露于 LCH 脉冲会影响豆娘的行为、生理和生存。鉴于豆娘在食物网动态中的重要作用，这些影响可能会转化为当地种群的损害，进而在生态系统边界内和跨生态系统产生自上而下的影响。
