CONGRESO LXV CONGRESSO NACIONAL DE BOTÂNICA BOTÁNICA XXXIV ERBOT - Encontro Regional de Botânicos MG, BA, ES 18 A 24 DE OUTUBRO DE 2014 - SALVADOR - BAHIA - BRASIL Latinoamericano de Botânica na América Latina: conhecimento, interação e difusão Would lianas and tree hosts be coevolved? A phylogenetic approach AUTOR(ES):Felipe Segala Ferreira;Juliano van Melis;Fernando Roberto Martins; INSTITUIÇÃO: Programa de Pós-Graduação em Biologia Vegetal Instituto de Biologia Universidade Estadual de Campinas. [email protected] Most parasitic plants feed on their hosts, but the climbing plants just use the physical structure of their supports, which can suffer reduction of reproductive rates and life expectancy. Since trees are resources for climbing plants, the reduction of reproductive rates and life expectancy that they can impose to trees seems not to be a good advantageous evolutionary strategy, because it could result in resource loss for the climbers over time. As the climbing plants have been present on earth for at least 500 million years, and the trees have not been extinguished over time, it seems that climbers have achieved a way to deal with the potential negative effects that they can cause to trees. Therefore, climbing plants could have coevolved with the tree hosts by circumventing the potential problems that they can cause to the hosts due to structural parasitism. We tested the hypothesis that recent associations between lianas and trees have occurred between coevolved parasites and hosts. We sampled 100 plots of 10 m x 10 m each, randomly distributed in 6.5 ha in a 245-ha fragment of the Semideciduous Seasonal Forest in southeastern Brazil. We sampled all lianas with diameter at breast height ≥ 1 cm in trees with circumference at breast height ≥ 15 cm. We used an algorithm to test the hypothesis of pairwise coevolution between parasites and their hosts by taking into account the degree of similarity of the positions that the parasites and their hosts occupy in their respective phylogenetic trees. We recorded 2,874 liana stems of 73 species, and 1,353 tree stems of 106 species. There were 727 different pairs of lianas (parasites) and trees (hosts), but neither the individual coevolution test for all pairs nor the global test were statistically significant. Our results do not point out to pairwise co-evolution between lianas and their tree hosts in the parasite-host context. Then, the coexistence between climbing plants and tree hosts might have proceeded over time by means of biological mechanisms not related to co-evolutionary pairwise processes.Palavras-chave: Assembling community, Brazil, Fahrenholtz’s rule, pairwise co-evolution, tropical forest.