Department of Entomology, College of Plant Protection, China Agricultural University, Beijing 100193, China.
INRA (French National Institute for Agricultural Research), Université Côte d'Azur, CNRS, UMR 1355-7254 Institute Sophia Agrobiotech, Sophia Antipolis 06903, France.
Chemosphere. 2019 Jul;226:651-658. doi: 10.1016/j.chemosphere.2019.03.114. Epub 2019 Mar 20.
Competition is a key structuring component of biological communities, which is affected by both biotic and abiotic environmental stressors. Among the latter, anthropic stressors and particularly pesticides are noteworthy due to their intrinsic toxicity and large use in agroecosystems. However this issue has been scarcely documented so far. In this context, we carried out experiments under laboratory conditions to evaluate stress imposed by the neonicotinoid insecticide imidacloprid on intra and interspecific competition among two major wheat pest aphids. The bird cherry-oat aphid Rhopalosiphum padi L. and the English grain aphid Sitobion avenae F. were subjected to competition on wheat seedlings under varying density combinations of both species and subjected or not to imidacloprid exposure. Intraspecific competition does take place without insecticide exposure, but so does interspecific competition between both aphid species with R. padi prevailing over S. avenae. Imidacloprid interfered with both intra and interspecific competition suppressing the former and even the latter for up to 14 days, but not afterwards when a shift in dominance takes place favoring S. avenae over R. padi, in contrast with the interspecific competition without imidacloprid exposure. These findings hinted that insecticides are indeed able to mediate species interaction and competition influencing community structure and raising management concerns for favoring potential secondary pest outbreaks.
竞争是生物群落的一个关键结构组成部分，它受到生物和非生物环境胁迫的影响。在后者中，人为胁迫，特别是杀虫剂，由于其内在的毒性和在农业生态系统中的大量使用而值得注意。然而，到目前为止，这个问题几乎没有被记录下来。在这方面，我们在实验室条件下进行了实验，以评估新烟碱类杀虫剂吡虫啉对两种主要小麦害虫蚜虫——禾谷缢管蚜和禾谷玉米蚜——种内和种间竞争的压力。在不同的两种蚜虫密度组合下，将鸟樱桃麦蚜和禾谷玉米蚜置于小麦幼苗上进行竞争，并对其进行或不进行吡虫啉暴露。在没有杀虫剂暴露的情况下，确实会发生种内竞争，但两种蚜虫之间也会发生种间竞争，禾谷缢管蚜会胜过禾谷玉米蚜。吡虫啉会干扰种内和种间竞争，抑制前者，甚至后者长达 14 天，但之后不会，此时会发生优势转变，禾谷玉米蚜会胜过禾谷缢管蚜，这与没有吡虫啉暴露的种间竞争形成对比。这些发现表明，杀虫剂确实能够调节物种间的相互作用和竞争，影响群落结构，并引起对潜在次要害虫爆发的管理关注。
