Phylogenetic relationships of Iberian dung beetles (Coleoptera: scarabaeinae): insights on the evolution of nesting behavior.

A phylogeny of the main lineages of dung beetles (Coleoptera: Scarabaeinae) from the Iberian Peninsula was based on partial nucleotide sequences (about 1221 bp) of the mitochondrial cytochrome oxidase I and II genes of 33 taxa. Our phylogenetic analyses confirmed the validity and composition of most of the recognized tribes within the subfamily. Interestingly, the Onitini showed an evolutionary rate significantly higher than that of the other tribes. The molecular phylogeny supports a sister-group relationship of the tribes Onitini and Oniticellini + Onthophagini. A close relationship of Scarabaeini, Gymnopleurini, and Sisyphini is also suggested but lacks bootstrap support. Surprisingly, the Coprini, which had always been related to the Oniticellini and Onthophagini, were placed closer to the Scarabaeini, Gymnopleurini, and Sisyphini. The inferred molecular phylogeny was used to assess the main evolutionary trends of nesting behavior. Our results suggest tentative single origins for both the tunneling and the rolling behaviors, and the possibility that the rolling behavior could have been lost secondarily in Copris.