Efeitos diretos e indiretos de características de plantas sobre a similaridade na composição de insetos herbívoros e parasitoides associados à Asteraceae

• Autor(a) principal: Alvarenga, Vinícius Silva de
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/8331
• topic: Análise de rota; Insetos endófagos; Interações tritróficas; Plantas hospedeiras; Parasitoides; Endophagous insects; Host-plant traits; Tritrophic interactions; Parasitic wasps; Path analysis; CIENCIAS BIOLOGICAS::ECOLOGIA

Understanding how interactions between trophic levels structure species composition is one of the main goals of ecological studies. Mechanisms that explain the compositional structure of parasitoid insects usually neglect the direct and indirect effects of plants’ characteristics, which can also determine the compositional structure of their host herbivore insects. In this context, our goal was to evaluate how plants’ characteristics (abundance, floral phenology, and phylogenetic distance) and herbivores’ compositional similarity determine parasitoids’ compositional similarity. As study system, we used Asteraceae species, flower-head feeding insects, and parasitoids. Using path analysis, we considered parasitoids and herbivores’ similarities, in qualitative (Sørensen similarity), quantitative (Bray-Curtis similarity), and phylogenetic proximity (taxonomic Sørensen similarity) terms. In general, we demonstrated that herbivores’ similarity is the major predictor of parasitoids’ similarity. Even though the effects of plants’ characteristics explained the smallest part of the variation in parasitoids’ similarity, these characteristics had inconsistent relative importance among the similarity indexes used here. Thus, our results indicate that although plant species constitute a potential additional barrier for the parasitoids of endophagous herbivores to find their insect hosts, herbivore parasitoids in flower heads of Asteraceae do not see the plant species in this way. The parasitoids respond mainly to the compositional variation of their insect hosts in the plant species that the latter consume. Therefore, we show how the composition of the upper trophic levels in this tri-trophic system is structured directly and indirectly by antagonistic interactions.