Hymenoptera Symphyta de Viçosa, Minas Gerais e bioecologia de Haplostegus nigricrus (Hymenoptera: Pergidae)

• Ano de defesa: 2008
• Autor(a) principal: Pereira, Alexandre Igor de Azevedo
• Orientador(a): Zanuncio, José Cola
• Banca de defesa: Santos, Germi Porto , Valicente, Fernando Hercos
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Entomologia
• Departamento: Ciência entomológica; Tecnologia entomológica
• País: BR
• Palavras-chave em Português: Pergidae; Monitoramento; Symphyta
• Palavras-chave em Inglês: Pergidae; Monitoring; Symphyta
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE
• Link de acesso: http://locus.ufv.br/handle/123456789/3873

The composition of the native Symphyta from a secondary forest of Viçosa, Minas Gerais state, Brazil, and the comparison between different sampling methods of that Hymenoptera, besides the register of guava, Psidium guajava (Myrtaceae), as host plant of the Neotropical Symphyta Haplostegus nigricrus Conde (Hymenoptera: Pergidae), and its ecological and biological aspects were studied. Three hundred and sixty three adults of Symphyta regarding to four families, 12 subfamilies, 17 genders, and 50 species were captured. The family Argidae was the most abundant with 66.68% of the collections proceeded by Pergidae (32.56%), Tenthredinidae (3.54%), and Cimbicidae (0.85%). The total number of Symphyta adults had positive correlation with the local temperature and rainfall. No adults were captured in the coldest months (June, July, and August) and, on the other months, that number varied from one to 89 adults. The sweeping vegetation was more efficient to capture Symphyta adults (n = 156) than Malaise (n= 35) and Moericke traps (n= 08). Adults of H. nigricrus were collected in a native forest and maintained in guava plants for obtaining clutches and neonate larvae that were reared with fresh leaves of P. guajava in the field. The adult and larval phases of H. nigricrus depend on guava leaves to deposit their eggs and to feed, respectively. Larvae of that insect have aposematic coloration and habits by aggregation and depend on this behavior to survive. The larval phase of H. nigricrus showed more number of natural enemies, while the pupa phase smaller viability at laboratory condictions, being bivoltine, and with strong correlation with the temperature and rainfall. The main larval defensive strategy of H. nigricrus seems to be the regurgitation and exhibition by its mouth of toxic compounds because the stink bug predators Podisus nigrispinus (Dallas), Supputius cincticeps (Stal), and Brontocoris tabidus (Signoret) (Heteroptera: Pentatomidae) died up to 24 hours after direct contact with that compounds. Only B. tabidus reached the adult phase with H. nigricrus larvae as food, what suggests larger tolerance and ability to detoxication the chemical compounds of that prey. The Symphyta community sampling shows the need to identify new species and register their hosts, and it also emphasizes the importance to establish actions for the preservation of forest areas, from Viçosa, that are in process of anthropic degradation. In spite of being a native herbivore, H. nigricrus does not have natural mortality agents able to reduce, drastically, its population and, besides, it has high egg viability and synchrony with the abiotic factors, and efficient defensive mechanisms against predators. Those characteristics can favor the adaptation of that herbivore to other native and exotic Myrtaceae with economic importance, mainly, due to the pressures exercised by the monocultures systems and fragmentation of their habitats.