Bentivenha J P F, Baldin E L L, Hunt T E, Paula-Moraes S V, Blankenship E E
Universidade Estadual Paulista, Faculdade de Ciências Agronômicas, Departamento de Proteção Vegetal, Botucatu, São Paulo, Brazil 18610-307 (
Department of Entomology, University of Nebraska-Lincoln, Haskell Agricultural Laboratory, Concord, NE 68728 (
Environ Entomol. 2016 Aug;45(4):999-1008. doi: 10.1093/ee/nvw068. Epub 2016 Jun 20.
The western bean cutworm Striacosta albicosta (Smith), the fall armyworm Spodoptera frugiperda (J. E. Smith), and the corn earworm Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) are among the major lepidopteran pests of maize in the United States, belonging to the same guild and injuring the reproductive tissues of this crop. Here, intraguild competition of these lepidopterans on non-Bt maize was evaluated through survival analysis of each species under laboratory and field conditions. Competition scenarios were carried out in arenas containing maize silk or ear tissue, using larvae on different stadium of development. Fitness cost competition studies were conducted to examine the influence of intraguild competition and cannibalism and predation rates on larval development. The survival of S. albicosta competing with the other species was significantly lower than in intraspecific competition, even when the larvae were more developed than the competitor. For S. frugiperda, survival remained high in the different competition scenarios, except when competing in a smaller stadium with H. zea Larvae of H. zea had a high rate of cannibalism, higher survival when competing against S. albicosta than S. frugiperda, and reduced survival when the H. zea larvae were at the same development stadium or smaller than the competitors. Based on fitness cost results, the absence of a competitor for the feeding source may confer an advantage to the larval development of S. frugiperda and H. zea Our data suggest that S. frugiperda has a competitive advantage against the other species, while S. albicosta has the disadvantage in the intraguild competition on non-Bt maize.
西部玉米螟Striacosta albicosta（史密斯）、草地贪夜蛾Spodoptera frugiperda（J. E. 史密斯）和棉铃虫Helicoverpa zea（博迪）（鳞翅目：夜蛾科）是美国玉米的主要鳞翅目害虫，属于同一类群，危害这种作物的生殖组织。在此，通过在实验室和田间条件下对每个物种进行生存分析，评估了这些鳞翅目昆虫在非转基因玉米上的种内竞争。竞争场景在含有玉米花丝或穗组织的实验场地中进行，使用处于不同发育阶段的幼虫。进行了适合度成本竞争研究，以检验种内竞争以及同类相食和捕食率对幼虫发育的影响。与其他物种竞争时，西部玉米螟的存活率显著低于种内竞争，即使其幼虫比竞争者发育得更成熟。对于草地贪夜蛾，在不同竞争场景下存活率都很高，除了在较小发育阶段与棉铃虫竞争时。棉铃虫幼虫同类相食率很高，与西部玉米螟竞争时的存活率高于与草地贪夜蛾竞争，且当棉铃虫幼虫处于相同发育阶段或比竞争者小时，存活率会降低。基于适合度成本结果，没有食物来源竞争者可能会赋予草地贪夜蛾和棉铃虫幼虫发育优势。我们的数据表明，草地贪夜蛾相对于其他物种具有竞争优势，而西部玉米螟在非转基因玉米的种内竞争中处于劣势。
