Pyrethroid insecticides have been used for decades and their worldwide market continues to increase, despite their high toxicity to non-target insects. Recent studies reveal that it is essential to investigate the secondary mechanisms of action of type II pyrethroids to understand their cellular effects on invertebrates. The aim of this study was to evaluate the lethality, behaviour and physiological alterations and energetic costs in caddisfly larvae exposed to environmentally relevant concentrations of esfenvalerate (ESF). ESF caused both mortality and feeding inhibition of exposed caddisfly larvae: nominal ESF 96 h LC₅₀ was 2.29 μg/L; feeding activity was impaired from concentrations equal or above 0.25 μg/L. At the cellular level, glutathione-S-transferase (GST) activity was increased on caddisfly larvae exposed to 0.25 and 0.5 μg/L ESF, which might contribute to prevent oxidative damage since levels of lipid peroxidation (LPO) were not altered. The energy budget of exposed caddisfly larvae was impaired from 0.25 μg/L ESF since sugar and protein contents decreased, while a decline of energy consumption was observed. The analysis of feeding and energy reserves and consumption data through structural equation modelling (SEM) allowed to quantify the direct and indirect effects of ESF exposure on bioenergetics of caddisfly larvae. SEM analysis showed a strong, negative direct influence of ESF onto feeding activity, sugars and energy consumption, highlighting a significant positive relationship between sugars and protein contents. These results show that energy expenditure is related to oxidative defense mechanisms induced by ESF stress that may lead to deleterious effects on growth and development.

中文翻译：

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与卵形丝状结肠瘤中乙戊戊酸酯暴露相关的能量消耗和生化生物标志物

拟除虫菊酯杀虫剂已经使用了数十年，尽管它们对非目标昆虫具有高毒性，但它们的全球市场仍在增长。最近的研究表明，至关重要的是研究II型拟除虫菊酯的次级作用机理，以了解它们对无脊椎动物的细胞作用。这项研究的目的是评估暴露于环境相关浓度的艾芬戊酸酯（ESF）的蝇幼虫的致死性，行为，生理变化和能量消耗。ESF导致暴露的线虫幼虫的死亡率和进食抑制：标称ESF 96 h LC ₅₀为2.29微克/升; 浓度等于或高于0.25μg/ L会损害进食活性。在细胞水平上，暴露于0.25和0.5μg/ L ESF的蝇幼虫的谷胱甘肽S-转移酶（GST）活性增加，这可能有助于防止氧化损伤，因为脂质过氧化（LPO）的水平没有改变。由于糖和蛋白质含量下降，暴露的蝇幼虫的能量收支从0.25μg/ L ESF降低，但观察到能量消耗下降。通过结构方程模型（SEM）对饲料，能量储备和消耗数据的分析，可以量化ESF暴露对蝇幼虫生物能的直接和间接影响。SEM分析显示，ESF对饲喂活动，糖和能量消耗具有强烈的负面直接影响，强调糖和蛋白质含量之间存在显着的正相关关系。这些结果表明，能量消耗与ESF压力诱导的氧化防御机制有关，这可能导致对生长发育的有害影响。