Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2015-10-26T13:53:50Z No. of bitstreams: 2 Dissertação - Paola Arielle Ferreira Nobre - 2015.pdf: 2865061 bytes, checksum: eb60843824dc4bc74edc88795332bc18 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-10-26T14:09:22Z (GMT) No. of bitstreams: 2 Dissertação - Paola Arielle Ferreira Nobre - 2015.pdf: 2865061 bytes, checksum: eb60843824dc4bc74edc88795332bc18 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-10-26T14:09:22Z (GMT). No. of bitstreams: 2 Dissertação - Paola Arielle Ferreira Nobre - 2015.pdf: 2865061 bytes, checksum: eb60843824dc4bc74edc88795332bc18 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-03-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / the factors that influence the choice of egg-laying sites by adult insects is critical in order to identify the major drivers of host-plant use by insects. The abundance of different plant species and the level of feeding specialization of insects have been considered as determinants of the preferential use of host-plants by herbivorous insects. We analyzed the host use patterns of endophagous insects that feed on Asteraceae flower-heads to test the following hypotheses: (i) the abundance of a plant species has a positive effect on the preference of herbivorous insects for that plant species, and (ii) the relative importance of plant abundance in determining preferential use is greater for herbivorous species that use a wider range of host-plant species. We used data on the interactions between herbivorous insects and Asteraceae host-plants family sampled in 20 Cerrado areas in São Paulo State. We analyzed 11 species of endophagous insects and 12 host-plant species. For eight species of herbivorous insects, plant species abundance showed a positive influence on herbivore preference. Three insect species did not respond to any influence of plant abundance on feeding preferences, but one of them showed a positive effect of plant species identity. Furthermore, both the most specialized and the most generalist insect species presented a stronger positive effect of plant species abundance in their choice of a host-plant. Therefore, our study shows that the abundance of plant species is a major factor determining the preferential use of hostplants by the endophagous insects of Asteraceae. Moreover, we show that herbivore diet breadth mediates the relationship between host use and plant abundance. / Estudos abordando interações entre insetos herbívoros e plantas hospedeiras abrangem uma vasta gama de aspectos ecológicos. Boa parte desses aspectos pode ser relacionada diretamente ou indiretamente com a alta dependência que os herbívoros apresentam em relação às suas plantas hospedeiras. Devido a essa alta dependência os insetos herbívoros respondem tanto à riqueza e densidade, quanto ao arranjo espacial das hospedeiras no habitat (Wright and Samways 1999, Summerville and Crist 2001, Tsharntke and Brandl 2004). Além das plantas hospedeiras proporcionarem recurso alimentar para os insetos, elas também fornecem abrigo e microclima adequado para o desenvolvimento dos imaturos (Gaston et al. 1992). Insetos herbívoros não consomem indiscriminadamente as plantas, havendo geralmente alguma preferência por poucas espécies de plantas hospedeiras (Futuyma and Gould 1979). Assim, mudanças, por exemplo, em aspectos quantitativo e qualitativo, nessas hospedeiras podem ter grandes efeitos sobre as populações desses herbívoros. Nesse contexto, pode-se dizer que a amplitude da dieta é um componente fundamental do nicho das espécies de insetos herbívoros, influenciando desde sua dinâmica populacional e suscetibilidade à extinção (Brown 1984), até sua distribuição geográfica (Strong et al. 1984).