Predador e presa de Culicidae: a interação em microcosmo aquático mediada por bactérias

• Ano de defesa: 2012
• Autor(a) principal: Simões, Daniel Albeny
• Orientador(a): Vilela, Evaldo Ferreira
• Banca de defesa: Campos, Ricardo Ildefonso de
• Tipo de documento: Tese
• Tipo de acesso: Acesso embargado
• 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: Aedes aegypti - Controle biológico; Dengue - Controle biológico; Toxorhynchites; Aedes triseriatus
• Palavras-chave em Inglês: Aedes aegypti - Biological control; Dengue - Biological control; Toxorhynchites; Aedes triseriatus
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::ENTOMOLOGIA AGRICOLA
• Link de acesso: http://locus.ufv.br/handle/123456789/940

Feeding by container-dwelling mosquito larvae may negatively affect microorganism richness or abundance. However, indirect effects of predators of mosquitoes on microorganisms are poorly studied. It is known that mosquito females are attracted to oviposit in high microorganism abundance containers. The response of ovipositing mosquitoes to chemical cues is an important part of mosquito ecology and control. This thesis consists of two chapters developed through experimental laboratory design. Chapter I: Larvae of the predator Toxorhynchites rutilus prey on larval Aedes triseriatus, which feed on bacteria. We postulated that a trophic-cascade arises from T. rutilus predation on A. triseriatus larvae, impacting bacterial abundance. As predicted, bacterial abundance was greater in the predator treatment than in others. Bacterial abundance did not differ between predator and predatory cues treatments. We hypothesized that predator and predatory cues treatments contain partially eaten prey, increasing bacteria abundance. Surprisingly, bacterial abundance was greater with real predation than in all other treatments. We suggest that feces (from either predator or prey) or reduced foraging induced by predator cues contributed to bacterial growth. Chapter II: The highly invasive Aedes aegypti preferentially oviposits in containers with high nutrient abundances; however, unlike many native species, A. aegypti does not appear to detect chemical cues of predaceous Toxorhynchites larvae, and therefore does not avoid ovipositing at sites containing these predators. Since predation by Toxorhynchites can potentially increase bacterial abundance in containers by reducing numbers of mosquito larvae and by adding substrates for bacterial growth, and since A. aegypti may prefer to oviposit where bacteria, which are the food of larvae, are abundant, it is possible that A. aegypti preferentially oviposit in containers where Toxorhynchites are abundant. We conducted a laboratory study in which gravid A. aegypti were offered two oviposition sites, combined in one of 6 treatments. Female A. aegypti preferentially oviposited in containers with active T. theobaldi predation, and also preferentially oviposited in containers with crushed A. aegypti, but displayed no oviposition preference in any other treatments. Our study supports the hypothesis that ovipositing A. aegypti are not attracted to sites with conspecifics or Toxorhynchites per se, but rather are attracted to sites with greater bacterial abundance.