title: Intraguild Competition of Three Noctuid Maize Pests.
abstract: 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.
authors.affiliation: Universidade Estadual Paulista, Faculdade de Ciências Agronômicas, Departamento de Proteção Vegetal, Botucatu, São Paulo, Brazil 18610-307 (jpgfdsilva@gmail.com; elbaldin@fca.unesp.br) jpgfdsilva@gmail.com.
authors.forename: J P F
authors.initials: JP
authors.lastname: Bentivenha
authors.affiliation: Universidade Estadual Paulista, Faculdade de Ciências Agronômicas, Departamento de Proteção Vegetal, Botucatu, São Paulo, Brazil 18610-307 (jpgfdsilva@gmail.com; elbaldin@fca.unesp.br).
authors.forename: E L L
authors.initials: EL
authors.lastname: Baldin
authors.affiliation: Department of Entomology, University of Nebraska-Lincoln, Haskell Agricultural Laboratory, Concord, NE 68728 (thunt2@unl.edu).
authors.forename: T E
authors.initials: TE
authors.lastname: Hunt
authors.affiliation: Embrapa Cerrados, BR 020 Km 18, Planaltina, Distrito Federal, Brazil 73310-970 (silpaulamoraes@gmail.com), and.
authors.forename: S V
authors.initials: SV
authors.lastname: Paula-Moraes
authors.affiliation: Statistics Department, University of Nebraska-Lincoln, Lincoln, NE 68583 (erin.blankenship@unl.edu).
authors.forename: E E
authors.initials: EE
authors.lastname: Blankenship
mesh_terms: D000818:Animals; D003163:Competitive Behavior; D005247:Feeding Behavior; D020387:Food Chain; D056084:Genetic Fitness; D007814:Larva / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D009036:Moths / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D003313:Zea mays / Q000254:growth & development
keywords: cannibalism; corn earworm; fall armyworm; intraguild predation; western bean cutworm