Phylogeny of Belidae (Coleoptera: Curculionoidea) based on rDNA sequences and morphology

FERRER, M. S.; MARVALDI, A. E.; SEQUEIRA, A. S

San Isidro, Buenos Aires – Argentina

Congreso; VII Reunión Argentina de Cladística y Biogeografía; 2007

Instituto de Botánica Darwinion

The family Belidae is a basal group of weevils with about 40 genera and 370 described species, distributed largely in the Southern Hemisphere (Kuschel 1959).  Phylogenetic reconstruction for these beetles is difficult due to the relictual distribution of the group and the apparent isolation of the genera. This is reflected by the abundance of characters that are autapomorphic to each of the genera, and the scarcity of ones supporting relationships among them.  Molecular data can provide additional evidence for phylogenetic reconstruction. We propose a phylogenetic hypothesis of Belidae, based on sequence data of two ribosomal genes combined with adult and larval morphology from previous studies (Kuschel & Leschen 2003, Marvaldi et al. 2006). We obtained DNA sequences (~ 2,300 bp) of the ribosomal genes 18S rDNA (mostly regions V4 & V7-V9) and 28S rDNA (D2 & D3 regions) from exemplars of  25 species representing both subfamilies, and the six tribes of Belidae.  Four outgroup taxa in Nemonychidae (Curculionoidea),  Megalopodidae and Cerambycidae (Chrysomeloidea) and Tenebrionidae (Tenebrionoidea) were also included. An alignment based on the secondary structure information of the rRNA molecule was performed (Kjer 1995). The data matrix was analyzed using parsimony and bayesian inference, obtaining similar results under both optimality criteria. The phylogenetic tree resulting from parsimony analysis of the combined morphological and molecular data recovers the monophyly of Belidae and their subfamilies and tribes. Groupings that were also recovered in the analysis of molecular data alone are: Belidae; Pachyurini, Belini, and Agnesiotidini; Metrioxenini + Aglycyderini; Oxycraspedina, and Allocorynina + Oxycorynina. Optimization of host preferences as a two-character state (gymnosperms, angiosperms) on the combined topology assigns gymnosperm feeding as the ancestral state for Belidae.  Further studies should improve the taxon sampling and focus on the dating of diversification of the family, to evaluate the scenario of the plant associations in such an ancient group.