Comportamento e morfologia das operárias de Atta sexdens rubropilosa (Hymenoptera: Formicidae) envolvidas na manipulação de lixo das colônias

• Ano de defesa: 2008
• Autor(a) principal: Lacerda, Fabrícia Gonçalves
• Orientador(a): Lúcia, Terezinha Maria Castro Della
• Banca de defesa: Moino Junior, Alcides , Araújo, Márcio da Silva
• 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: Antibióticos; Formigas cortadeiras; Lixo; Patógenos; Glândula metapleural
• Palavras-chave em Inglês: Antibiotics; Leaf-cutting ants; Waste; Pathogens; Metapleural gland
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE
• Link de acesso: http://locus.ufv.br/handle/123456789/858

This was a three-parts research, conducted in Insectary of the Federal University of Viçosa (UFV), in the Laboratory of Mycorrhizal Associations (UFV) and also in the Laboratory of Cellular Biology and Biophysics (UFV). The species of leaf-cutting ant used was Atta sexdens rubropilosa Forel. In the first work, it was verified that when waste workers and foragers are put on the fungus garden, the first ones receive more grooming, they were more inspected and immobilized by the nestmates of the fungus garden. Such behaviors did not differ among colonies that had the waste artificially contaminated by spores of Escovopsis weberi Muchovej & Della Lucia and the ones that were not contaminated. The behaviors of grooming, inspection and immobilization can represent behavioral strategies to avoid the contamination of the colony by the garbage. The behavior of self-grooming was similar in waste workers and foragers when put on the fungus garden and it did not differ in contaminated colonies and no-contaminated colonies. There was not aggressiveness by workers of the fungus garden towards the waste workers and foragers. In rare occasions, hostility was observed. It was also more intense towards waste workers and in non-contaminated colonies. The microbial analysis of body surface in the waste workers and gardeners of the non-contaminated colonies by E. weberi revealed the presence of Trichoderma, an antagonist of the fungus garden, among other saprophytes and pathogens of plants. It was verified that 83,28% of the workers of the waste are not confined to that compartment; they could move freely through out the colony. In the second part of the research, it was verified that tasks as the care inside the garden are frequent throughout the workers' life, in spite of their decrease in occurrence in the last weeks of these ant s life. The foraging activities also occurred during the whole period of the workers' life, becoming more frequent at the end of their lifespan. Therefore, the workers present age polyethism in relation to the tasks inside the fungus garden and to the foraging. On the other hand, the work in the garbage occurs during the lifetime of the waste workers, being more frequent in their first weeks of life. Likewise, the age polyethism does not apply to the tasks related to the waste of the colony. It was verified also, that the predominant caste, in number of workers, in the waste chamber of the colony was the gardeners followed by the generalists, foragers and soldiers. It was also verified that waste workers are capable of taking care of the fungus garden, however, the frequency of this care is lower than that by the workers that usually work in that site. Waste workers exhibited brood care and foraging similar to those of non-waste workers. However, with respect to the waste, the frequency of waste workers working in the garbage chamber was higher than that of the other workers. Therefore, waste workers are able to engage in the several tasks of the colony. In the third bioassay, it was verified that waste workers, waste transporters and foragers had larger volume of the reservoir of the metapleural gland, which produces antibiotics, than workers of the fungus garden of same size. The reservoir volume of the gland did not differ among the first three castes. The relationship nucleus-cytoplasm as well as the area of surface of the bulla of the metapleural gland did not differ among the four classes of workers. It was concluded that the workers, that perform tasks outside of the colony, which are exposed more intensely to the risks of parasitism, are morphologically better equipped, since they possess more developed metapleural gland.