Pearsons Kirsten Ann, Lower Sarah E, Tooker John F
Department of Entomology, Pennsylvania State University, University Park, PA, United States of America.
Biology Department, Bucknell University, Lewisburg, PA, United States of America.
PeerJ. 2021 Nov 19;9:e12495. doi: 10.7717/peerj.12495. eCollection 2021.
Previous research suggests that fireflies (Coleoptera: Lampyridae) are susceptible to commonly used insecticides. In the United States, there has been a rapid and widespread adoption of neonicotinoid insecticides, predominantly used as seed coatings on large-acreage crops like corn, soy, and cotton. Neonicotinoid insecticides are persistent in soil yet mobile in water, so they have potential to contaminate firefly habitats both in and adjacent to application sites. As a result, fireflies may be at high risk of exposure to neonicotinoids, possibly jeopardizing this already at-risk group of charismatic insects.
To assess the sensitivity of fireflies to neonicotinoids, we exposed larvae of complex and to multiple levels of clothianidin-treated soil and monitored feeding behavior, protective soil chamber formation, intoxication, and mortality.
and larvae exhibited long-term intoxication and mortality at concentrations above 1,000 ng g soil (1 ppm). Under sub-lethal clothianidin exposure, firefly larvae fed less and spent less time in protective soil chambers, two behavioral changes that could decrease larval survival in the wild.
Both firefly species demonstrated sub-lethal responses in the lab to clothianidin exposure at field-realistic concentrations, although and appeared to tolerate higher clothianidin exposure relative to other soil invertebrates and beetle species. While these two firefly species, which are relatively widespread in North America, appear somewhat tolerant of neonicotinoid exposure in a laboratory setting, further work is needed to extend this conclusion to wild populations, especially in rare or declining taxa.
先前的研究表明萤火虫（鞘翅目：萤科）对常用杀虫剂敏感。在美国，新烟碱类杀虫剂已迅速广泛采用，主要用作玉米、大豆和棉花等大面积农作物种子的包衣剂。新烟碱类杀虫剂在土壤中具有持久性但在水中具有流动性，因此它们有可能污染施药地点及其附近的萤火虫栖息地。因此，萤火虫可能面临高风险接触新烟碱类物质，这可能危及这群本就处于危险中的魅力昆虫。
为评估萤火虫对新烟碱类物质的敏感性，我们将复杂种和另一种萤火虫的幼虫暴露于多个水平的噻虫胺处理过的土壤中，并监测其取食行为、保护性土壤腔室的形成、中毒情况和死亡率。
当土壤浓度高于1000纳克/克（1 ppm）时，两种萤火虫幼虫均表现出长期中毒和死亡情况。在亚致死剂量的噻虫胺暴露下，萤火虫幼虫进食减少，在保护性土壤腔室中停留的时间减少，这两种行为变化可能会降低野外幼虫的存活率。
在实验室中，两种萤火虫对田间实际浓度的噻虫胺暴露均表现出亚致死反应，尽管相对于其他土壤无脊椎动物和甲虫物种，这两种萤火虫似乎能耐受更高浓度的噻虫胺。虽然这两种在北美相对广泛分布的萤火虫在实验室环境中似乎对新烟碱类物质暴露有一定耐受性，但仍需要进一步研究将这一结论推广到野生种群，尤其是罕见或数量减少的类群。
