Department of Biology, University of Florence, Via Madonna del Piano, 6, Sesto F.No., 50019, Florence, Italy.
Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, University of South Bohemia in České Budějovice, Zátiší, 728/II, 38925, Vodňany, Czech Republic.
Environ Sci Pollut Res Int. 2023 Feb;30(10):27501-27509. doi: 10.1007/s11356-022-24100-7. Epub 2022 Nov 16.
Despite several restrictions to their use, neonicotinoid insecticides are still widely employed worldwide. Residual sub-lethal amounts of these chemicals can have detrimental effects on the behavior of non-target insects. Toxic effects on economically important species such as bees have been widely documented, but less is known about their toxic action on other social insects, such as ants. In this study, we assessed the effect of different sub-lethal doses of the neonicotinoid imidacloprid on the ability of colonies of the invasive ant Lasius neglectus to select the most profitable resource. We used Y-shaped mazes having an imidacloprid-polluted or an unpolluted sucrose solution on the two branches. Two sucrose (0.1 M, 0.5 M) and two imidacloprid (1 μg/ml, 10 μg/ml) concentrations were used. In parallel, we evaluated the marking activity of foragers who fed on the same solutions. We found that the 0.1 M sugar solution polluted with 1 μg/ml imidacloprid was significantly more frequently selected in binary choices experiments than the unpolluted resource. Moreover, the ingestion of the same combination of sugar and imidacloprid significantly increased the marking rate of foragers. The higher concentration of the pollutant had lower effects, probably because of the hormesis phenomenon. Results suggest that the lower sub-lethal dose of imidacloprid can lead ants to select again the polluted resource. This "active" selection of the pollutant may magnify the negative effects on the colonies. Due to their ecological role, any impairment of ant survival or behavior may have detrimental cascade effects on the whole ecosystem.
尽管对其使用有一些限制，但新烟碱类杀虫剂仍在全球范围内广泛使用。这些化学物质残留的亚致死量可能对非靶标昆虫的行为产生有害影响。新烟碱类杀虫剂对经济上重要的物种（如蜜蜂）的毒性作用已被广泛记录，但对其他社会性昆虫（如蚂蚁）的毒性作用知之甚少。在这项研究中，我们评估了不同亚致死剂量的新烟碱类杀虫剂噻虫啉对入侵蚂蚁 Lasius neglectus 种群选择最有利资源的能力的影响。我们使用 Y 形迷宫，其两个分支上分别有噻虫啉污染或无污染的蔗糖溶液。使用了两种蔗糖（0.1 M，0.5 M）和两种噻虫啉（1 μg/ml，10 μg/ml）浓度。同时，我们评估了采食同一溶液的觅食者的标记活动。我们发现，在二元选择实验中，污染有 1 μg/ml 噻虫啉的 0.1 M 糖溶液比无污染资源更频繁地被选择。此外，采食相同的糖和噻虫啉组合显著增加了觅食者的标记率。较高浓度的污染物的效果较低，这可能是由于激素效应现象。结果表明，较低的亚致死剂量的噻虫啉可能导致蚂蚁再次选择污染的资源。这种对污染物的“主动”选择可能会放大对蚁群的负面影响。由于它们的生态作用，任何对蚂蚁生存或行为的损害都可能对整个生态系统产生不利的级联效应。
