Neonicotinoid insecticides can pose a severe threat to grassland plant bug communities

Although pesticides have been proposed as one of the main causes of insect
decline, there are still few studies assessing their effects on non-target
species under field conditions. Here we investigated the effects of the
neonicotinoid insecticide Mospilan®SG (active ingredient acetamiprid) on
plant bugs (Heteroptera: Miridae), a dominant group of European grassland
insect communities. In a controlled field study, the abundance of three
focal species was reduced by up to 92% two days after field exposure at
concentrations expected at field margins, with mortality varying among
species. Follow-up feeding assays with insecticide-treated host plants in
the greenhouse and controlled dose-response laboratory assays confirmed
the strong negative effects on non-target species. Strikingly, when
comparing the lethal dose 50 derived from Mospilan®SG with a value
reported for honeybees using another acetamiprid formulation, the
insecticide was over 11,000 times more toxic to plant bugs than to
honeybees. In addition, males were 20 times more sensitive than females in
two tested species. Thus, continuous exposure to this neonicotinoid may
reduce plant bug populations and promote insecticide-tolerant species,
altering community composition. We suggest that sex-specific sensitivity
be considered in risk assessment and conclude that the true risk to
non-target insects is currently greatly underestimated.

尽管农药被认为是昆虫种群衰退的主要诱因之一，但目前仍鲜有研究在野外条件下评估其对非靶标物种（non-target species）的影响。本研究针对新烟碱类杀虫剂（neonicotinoid insecticide）Mospilan®SG（有效成分：啶虫脒（acetamiprid））对欧洲草原昆虫群落优势类群——盲蝽（半翅目：盲蝽科，Heteroptera: Miridae）的影响展开探究。在受控野外实验中，以田边预期浓度进行野外暴露处理两天后，三种目标受试物种的种群丰度最高下降92%，且不同物种的死亡率存在差异。后续通过温室中经杀虫剂处理的寄主植物开展的取食实验（feeding assays），以及受控剂量-反应（dose-response）实验室实验，均证实了该杀虫剂对非靶标物种的显著负面影响。值得注意的是，将本研究中Mospilan®SG的半数致死剂量（lethal dose 50，LD50），与此前针对蜜蜂使用另一款啶虫脒制剂所报道的数值相比，该杀虫剂对盲蝽的毒性是其对蜜蜂毒性的11000倍以上。此外，在两种受试物种中，雄性个体的敏感性是雌性的20倍。因此，持续暴露于该新烟碱类杀虫剂可能会降低盲蝽种群数量，并筛选出耐杀虫剂物种，进而改变群落组成。我们建议在风险评估中纳入性别特异性敏感性因素，并得出结论：当前对非靶标昆虫的真实风险被严重低估了。