Orientadores: Angelo Pires do Prado, Thomas Michael Lewinsohn / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-09-11T21:19:37Z (GMT). No. of bitstreams: 1 Braun_MarinaReiter_D.pdf: 4685052 bytes, checksum: 6fca81032502f6931c9f8333e10b544b (MD5) Previous issue date: 2011 / Resumo: Na presente tese foram descritas dez novas espécies de Agromyzidae endófagos de capítulos de Asteraceae. Essas espécies estão distribuídas nas duas subfamílias representadas nos gêneros Melanagromyza, Ophyomyia (Agromyzinae), Calycomyza e Liriomyza (Phytomyzinae). No gênero Melanagromyza, segundo maior da família, foram descritas sete novas espécies. Pela primeira vez foi encontrada nos gêneros Calycomyza, Liriomyza e Ophyomyia a herbivoria de capítulos de asteráceas. Além de aumentar o conhecimento sobre a diversidade do grupo, outra contribuição desta tese é a avaliação da especialização alimentar do grupo, que mantém o padrão da família com uma baixa proporção de generalistas. A partir dos dados de interação desses endófagos construímos uma rede de interações entre quinze espécies de Melanagromyza e suas plantas hospedeiras com o objetivo de avaliar sua estrutura de interações. Esta rede foi testada para investigar a existência de aninhamento e compartimentalização dessas interações. Outras questões investigadas foram a relação entre afinidade morfológica dos herbívoros e sua utilização de recursos, além do parentesco das plantas hospedeiras utilizadas pelas espécies de herbívoros. A estrutura de interações dessa rede possui um padrão bastante compartimentalizado, o que era esperado em interações de herbivoria entre insetos que apresentam alta especialização alimentar. Quanto aos efeitos do parentesco na estruturação da rede de interações, verificamos resultados diferentes para os insetos e as plantas. A classificação das espécies de Melanagromyza conforme sua morfologia genital não teve relação com o grupamento dos herbívoros análise de agrupamento bidirecional. Por outro lado, para as plantas, observamos grande concordância entre a classificação taxonômica das espécies e os grupos formados a partir da análise de agrupamento bidirecional / Abstract: This study describes ten new species of endophagous Agromyzidae of Asteraceae flower-heads. Those species belong to genera of the two subfamilies, respectively Melanagromyza, Ophyomyia (Agromyzinae), Calycomyza and Liriomyza (Phytomyzinae). In Melanagromyza, the second largest genus in the family, seven new species were described. Herbivory of Asteraceae flower-heads was recorded for the first time in Calycomyza, Liriomyza and Ophyomyia. Besides increasing the knowledge of agromyzid diversity, this study contributes to the evaluation of host range patterns in the family, which confirms that most agromyzids are specialized on a plant genus or tribe, with a small percentage of generalistic species. From the feeding records between endophages and their host plants we built an interaction matrix, in order to evaluate their interaction structure. The network shows both a nested and a compartmented pattern, suggesting a compound structure. The structure of the analyzed network has both a nested and a compartmented pattern. Compartmentation is expected for interactions between herbivore insects with such specialized feeding habits. In addition, other issues were investigated in this study: Do morphologically similar herbivore species use the same plants? Are plants used by the same herbivore species phylogenetically related? Regarding the family relationship based on the interactions structure, we found divergent results for insects and for plants. The categorization of Melanagromyza species based on their male genital morphology showed no relation with the herbivore groups based on their host use in a bidirectional cluster analysis. On the other hand, plants showed strong agreement between the taxonomic affinities of the species and the groups based on their shared herbivores in the bidirectional analysis / Doutorado / Ecologia / Doutor em Ecologia

Host-Associated Differentiation (HAD) is the formation of genetically divergent hostassociated lineages maintained by ecological isolation. HAD is potentially an important route to ecological speciation in parasites including many insects. While HAD case studies are accumulating, there is a dearth of negative results in the literature making it difficult to know how common the phenomenon really is or whether there are specific traits of parasites which promote HAD. To address these two problems, studies are needed which both publish negative results (i.e., parasites not showing HAD) and test for HAD in multiple parasite species on the same pair of host species (i.e., control for host plant effects). In this study, HAD was tested in three species of herbivorous insects and one parasitoid species on the same two host tree species: pecan and water hickory. The insects were selected based on the presence or absence of two traits, parthenogenesis and endophagy. A test for HAD was considered “positive” when population substructure was explained by host-association. To test for the presence of HAD, insects were sampled sympatrically to eliminate geographical isolation as a confounding factor, sampling was replicated spatially to assure that HAD persisted, and multiple loci were sampled from each individual. Genetic data was analyzed using cluster analyses. HAD was found in both pecan leaf phylloxera and yellow pecan aphid but not in pecan bud moth or in the parasitoid of the yellow pecan aphid, Aphelinus perpallidus. Interestingly, both taxa showing HAD are parthenogenetic and both taxa not showing HAD reproduce sexually. Species showing HAD were tested for the presence of a pre-mating reproductive isolating mechanism (RIM) which could be maintaining HAD despite the potential for gene flow. Selection against migrants to the alternative host was tested in yellow pecan aphid using a no-choice fitness experiment. The overall contribution of this RIM to total isolation was positive and ranged from 0.614 to 0.850. The RIM of “habitat preference” was tested in pecan leaf phylloxera using a dual-choice preference experiment. In this species, preference was only detected for phylloxera originating from water hickory suggesting that host discrimination ability may be a less important factor promoting differentiation in phylloxera.