Mitochondrial DNA in the Bark Weevils: Phylogeny and evolution in the Pissodes strobi species group (Coleoptera: Curculionidae)

The genus Pissodes (Coleoptera: Curculionidae) contains four species informally grouped into the P. strobi species group: P. strobi, P. nemorensis, P. terminalis, and P. schwarzi. These species have been the focus of extensive investigations into their behavior and ecology in relation to reproductive isolation and evolution. We examined restriction-site polymorphism and divergence of mitochondrial DNA in these species and in an outgroup, P. affinis. Both diversity and divergence are high relative to that seen in other insects studied. Nucleotide diversity is 0.1%-1.3% within species, and net divergence among species is 2.0%-16.0%. Phylogenetic relationships of mitochondrial DNA haplotypes directly contradict several hypotheses of species relationship from previous studies of morphology, allozyme, and cytogenetic data indicating that mitochondrial and nuclear genes have evolved in distinctly different manners. Hybridization among species and high rates of sequence change may have contributed to these contradictions.