Ecologia química de Elasmopalpus lignosellus (Zeller): comunicação química durante o comportamento reprodutivo e a interação tritrófica envolvendo milho e o parasitóide Trichogramma pretiosum Riley

• Ano de defesa: 2010
• Autor(a) principal: Xavier, Luciane Modenez Saldivar
• Orientador(a): Vilela, Evaldo Ferreira
• Banca de defesa: Waquil, José Magid , Diniz, Ivone Rezende , Michereff Filho, Miguel , Pires, Carmen Sílvia Soares
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Entomologia
• Departamento: Ciência entomológica; Tecnologia entomológica
• País: BR
• Palavras-chave em Português: Comportamento sexual; Acasalamento; Produção feromonal; Compostos orgânicos voláteis; Defesa indireta
• Palavras-chave em Inglês: Sexual behavior; Mating; Pheromonal production; Volatile organic compounds; Indirect defense
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE
• Link de acesso: http://locus.ufv.br/handle/123456789/883

The tritrophic system in maize, Elasmopalpus lignosellus (Zeller, 1848) (Lepidoptera: Pyralidae) and Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae) was evaluated aiming to identify if the feeding behavior of E. lignosellus larvae induces the indirect defense of maize plants and also if induced volatiles, after damage by herbivory, are used by the T. pretiosum as cues to find their host. The amount of volatile compounds emitted by maize plants, subjected to different treatments (undamaged, damaged by herbivory and mechanically damaged), differed significantly when compared. The results of bioassays with the maize plants subjected to the different treatments with egg parasitoids, suggest that T. pretiosum use maize volatiles as clues to find the host. After 24h of damage, the analysis of the main curves did not detect differences between undamaged plants and plants damaged by herbivory. However, individually, the compounds (Z)-3-hexenyl acetate, benzothiazole and terpenes, β-pinene, β-myrcene and (E)-4,8-dimethyl-1,3,7-nonatriene were released in higher quantities by plants damaged by herbivory when compared to the quantity released by undamaged plants. The study of reproductive behavior showed that the highest index of mating occurred when the couples were between 24 and 48 hours old and between 6 and 8 hours of darkness. In the mating behavior, the males usually vibrated their wings when approaching the female and the average period of mating was 93.97 ± 4.13 minutes. Calling females of E. lignosellus, were evaluated in a wind tunnel and attracted significantly more males than in bioassays with clean air (control). Younger females call significantly less, but no significant effect occurred in male response. Males with 48 to 72 hours old responded less and differed significantly from other males assessed, but the age of the female did not influence the response. The time of response in each bioassay (10 minutes/bioassay) was significantly higher for males aged between 48 and 72 hours old, when males of 0-24, 24-48, 48-72 and 72-96 hours old were compared. Different analytical techniques were tested in the extraction of the sex pheromone of E. lignosellus: aeration, extraction of glands and Solid Phase Micro-Extraction (SPME). The aeration technique and SPME fiber technique showed little consistency and results with high variability. The gland extraction process was the most efficient technique, in which it was possible to identify only three compounds with the fragmentation pattern expected for lepidopteran acetates. The chemical analysis of extracts showed that the compounds are hexadecyl acetate, (Z)-11-hexadecenyl acetate and (Z)-9 or (Z)-8-hexadecenyl acetate.