Pesticides are a crucial tool to control introduced pest species, facilitating restoration of native ecosystems and reducing mortality risk in endemic species. However, non-target species, including many invertebrates, consume pesticides. Although lethal effects on these non-target species are often documented, sub-lethal effects are poorly understood. New Zealand presents a unique case study in this field, with a range of introduced mammalian pest species that threaten a large proportion of endemic fauna. Current research suggests that vertebrate pesticide baits do not cause mortality in invertebrate consumers, but few studies investigate sub-lethal behavioural effects. In this study, we tested whether consumption of a widely dispersed anticoagulant rodenticide, brodifacoum, influenced the expression and repeatability of behaviour in a known consumer of the bait, Wellington tree weta ( Hemideina crassidens) over a 40-day treatment period. We compared refuge emergence, activity, refuge-seeking tendencies and defensive responses of brodifacoum-exposed and untreated control weta. Bait-exposed individuals showed increased emergence but decreased activity, boldness and aggression compared to untreated controls. These results show that brodifacoum, although not directly causing mortality, may alter behaviours directly related to foraging, mating, competitive interactions and anti-predator responses, which could be detrimental to fitness and survival. More research should be undertaken to investigate the capacity for H. crassidens to tolerate exposure, and to determine any age- or duration-related responses. These results should also be a catalyst for further research on non-target behavioural effects in other pesticide-exposed insect species.

中文翻译：

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哺乳动物杀虫剂诱饵的亚致死暴露改变了直翅目动物的行为

农药是控制引入害虫物种、促进本地生态系统恢复和降低地方性物种死亡风险的重要工具。然而，包括许多无脊椎动物在内的非目标物种会消耗杀虫剂。尽管经常记录对这些非目标物种的致命影响，但人们对亚致死影响知之甚少。新西兰在该领域提供了一个独特的案例研究，引入了一系列威胁到大部分地方性动物群的哺乳动物害虫物种。目前的研究表明，脊椎动物杀虫剂诱饵不会导致无脊椎动物消费者死亡，但很少有研究调查亚致死行为影响。在这项研究中，我们测试了广泛分布的抗凝血灭鼠剂溴鼠灵的消费是否 在 40 天的治疗期内，影响了已知诱饵消费者 Wellington tree weta (Hemideina crassidens) 的行为表达和可重复性。我们比较了暴露和未处理的对照湿蚊的避难出现、活动、寻求避难的倾向和防御反应。与未经处理的对照组相比，暴露于诱饵的个体表现出增加的出现，但减少了活动、胆量和攻击性。这些结果表明，brodifacoum 虽然不会直接导致死亡，但可能会改变与觅食、交配、竞争性互动和反捕食者反应直接相关的行为，这可能对健康和生存有害。应该进行更多的研究来调查 H. crassidens 耐受暴露的能力，并确定任何与年龄或持续时间相关的反应。