Institute of Environmental Sciences, Leiden University, 2300 RA Leiden, The Netherlands;
Institute of Environmental Sciences, Leiden University, 2300 RA Leiden, The Netherlands.
Proc Natl Acad Sci U S A. 2021 Nov 2;118(44). doi: 10.1073/pnas.2105692118.
There is an ongoing unprecedented loss in insects, both in terms of richness and biomass. The usage of pesticides, especially neonicotinoid insecticides, has been widely suggested to be a contributor to this decline. However, the risks of neonicotinoids to natural insect populations have remained largely unknown due to a lack of field-realistic experiments. Here, we used an outdoor experiment to determine effects of field-realistic concentrations of the commonly applied neonicotinoid thiacloprid on the emergence of naturally assembled aquatic insect populations. Following application, all major orders of emerging aquatic insects (Coleoptera, Diptera, Ephemeroptera, Odonata, and Trichoptera) declined strongly in both abundance and biomass. At the highest concentration (10 µg/L), emergence of most orders was nearly absent. Diversity of the most species-rich family, Chironomidae, decreased by 50% at more commonly observed concentrations (1 µg/L) and was generally reduced to a single species at the highest concentration. Our experimental findings thereby showcase a causal link of neonicotinoids and the ongoing insect decline. Given the urgency of the insect decline, our results highlight the need to reconsider the mass usage of neonicotinoids to preserve freshwater insects as well as the life and services depending on them.
昆虫的丰富度和生物量都在以前所未有的速度减少。广泛认为，杀虫剂的使用，尤其是新烟碱类杀虫剂的使用，是导致这种减少的一个因素。然而，由于缺乏野外现实实验，新烟碱类对自然昆虫种群的风险在很大程度上仍然未知。在这里，我们使用户外实验来确定常用新烟碱噻虫嗪在野外现实浓度下对自然组装的水生昆虫种群出现的影响。施药后，所有主要的水生昆虫目（鞘翅目、双翅目、蜉蝣目、蜻蜓目和鳞翅目）的数量和生物量都明显下降。在最高浓度（10μg/L）下，大多数目几乎没有出现。在更常见的观察浓度（1μg/L）下，最丰富的科摇蚊科的物种多样性下降了 50%，而在最高浓度下，通常只剩下一个物种。因此，我们的实验结果展示了新烟碱类和正在进行的昆虫减少之间的因果关系。鉴于昆虫减少的紧迫性，我们的结果强调需要重新考虑大量使用新烟碱类来保护淡水昆虫以及依赖它们的生命和服务。
