IADIZA   20886
INSTITUTO ARGENTINO DE INVESTIGACIONES DE LAS ZONAS ARIDAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Unveiling the source area of an insect of the Monte Desert associated with parasitic plants
Autor/es:
FERRER, MARÍA SILVIA; MARVALDI, ADRIANA ELENA; SEQUEIRA, ANDREA SILVIA
Lugar:
La Plata, Buenos Aires
Reunión:
Congreso; IX Reunión Argentina de Cladística y Biogeografía; 2010
Institución organizadora:
Facultad de Ciencias Naturales y Museo de La Universidad Nacional de La Plata
Resumen:
Weevils of the family Belidae (Coleoptera: Curculionoidea) show intriguing evolutionary shifts among host-plants. The belids are a relatively small and ancient group, with about 360 described species worldwide, showing a distribution largely confined to the Southern Hemisphere. They are classified in 38 genera and two subfamilies: Belinae and  Oxycoryninae. Members of the American tribe Oxycorynini have enigmatic associations with both angiosperm and gymnosperm plants, being represented by 13 species in four genera endemic of South America and by four species and three genera in Central America, Mexico and the Caribbean. Phylogenetic studies of Belidae reveal a pattern of host use that is common to other phytophagous beetles: basal lineages retain their ancestral associations with conifers since the Mesozoic. When relationships and character changes within each belid subgroup are explored, it becomes evident that shifts to phylogenetically distant plants have occurred. The oxycorynines show shifts to parasitic angiosperms (Balanophoraceae and Hydnoraceae) in South America, and to gymnosperm cycads (Zamia and Dioon) in Central America, and these changes are thought to have played an important role in the diversification of the group. The oxycorynine species Hydnorobius hydnorae develop in parasitic angiosperm plants of the genus Prosopanche (Hydnoraceae). This weevil is endemic of Argentina, distributed in the biogeographic province of Monte desert. The life history of Hydnorobius hydnorae is tightly linked with that of the host-plant. The present study is aimed to explore the geographical origin of the association of the weevil Hydnorobius hydnorae with its host plant Prosopanche americana, based on the relationships among genotypes from nine populations of H. hydnorae sampled from localities covering most of the distribution range of the species. Haplotypes were identified using the Cytochrome B mitochondrial marker. Descriptive statistics and phylogeographic analyses were performed using the mitochondrial genetic data of individuals. The distribution in the past of the host-plant was estimated using predictive models of species distribution employing paleoclimatic variables. The past distribution of Prosopanche was related with the estimated ancestral range of the weevil species. These pieces of information together help clarify the evolution of the association of Hydnorobius hydnorae with its host-plant Prosopanche, as well as the ancestral range and demographic history of this weevil species. The results of this study provide insights into the evolution of host choices in this ancient weevil group.