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Coneworms of the genus Dioryctria Zeller include several serious pests of conifer seeds that are notoriously difficult to distinguish as species. We surveyed mitochondrial DNA variation within the abietella species group by sequencing 451 bp of cytochrome oxidase subunit 1 (COI) and 572 bp of cytochrome oxidase subunit 2 (COII) genes from 64 individuals of six major species in the group. In addition to examining phylogenetic relationships within European members of the group, the study focused on the two most damaging species, D. abietivorella Grote from North America and D. abietella Denis & Schiffermüller from Europe and Asia, which have been considered taxonomically synonymous in the past. To detect different levels of divergence, we extensively sampled in seed orchards and natural forests for D. abietella on different hosts. Maximum parsimony and maximum likelihood analyses confirmed the monophyly of the abietella species group and its separation into three clades. The grouping of North American species (clade A) received strong support in both analyses, whereas relationships between clade A and the two European clades were weakly supported. Dioryctria simplicella Heinemann could not be unambiguously separated from D. abietella populations. The diverse haplotypes observed in the network analysis conducted with eight populations of polyphagous D. abietella suggested the presence of two distinct lineages in France. [ABSTRACT FROM AUTHOR]

Phylogeographic studies are often focused on temperate European species with relict footholds in the Mediterranean region. Past climatic oscillations usually induced range contractions and expansions from refugial areas located in southern Europe, and spatial distribution of genetic diversity show that northward expansions were usually pioneer-like. Actually, few studies have focused on circum-Mediterranean species, which probably were not influenced in the same way by climatic oscillations. We present the phylogeography of the bark beetle Tomicus destruens, which is restricted to the whole Mediterranean basin and the Atlantic coasts of North Africa and Portugal. We systematically sequenced 617 bp of the mitochondrial genes COI and COII for 42 populations ( N = 219). Analysis revealed 53 haplotypes geographically structured in two clades, namely eastern and western clades, that diverged during the Pleistocene. A contact zone was identified along the Adriatic coast of Italy. Interestingly, we found contrasting levels of genetic structure within each clade. The eastern group was characterized by a significant phylogeographic pattern and low levels of gene flow, whereas the western group barely showed a spatial structure in haplotype distribution. Moreover, the main pine hosts were different between groups, with the Aleppo-brutia complex in the east and the maritime pine in the west. Potential roles of host species, climatic parameters and geographical barriers are discussed and the phylogeographic patterns are compared to classical models of postglacial recolonization in Europe. [ABSTRACT FROM AUTHOR]

A mitochondrial DNA (mtDNA) study, based on 43 European populations (33 of them sampled in France) of Monochamus galloprovincialis, vector of the pinewood nematode, and 14 populations of its sister species Monochamus sutor was realized. Sequencing of 792 bp of the cytochrome oxidase I (COI) and 521 bp of the COII genes revealed numerous ambiguities on multiple nucleotide sites for half of M. galloprovincialis specimens studied (44.8%). Hypotheses of heteroplasmy and pseudogenes ( Numts) were examined. The mtDNA isolation by alkaline lysis and cloning (for three successfully used individuals) both support the hypothesis that the ambiguous sequences amplified were not of mtDNA nature and validate the presence of Numts in the nuclear genome of M. galloprovincialis. Multiple copies of mtDNA-like sequences were found paralogous to COI, tRNA leucin and COII regions. Phenetic analysis placed different recently diverged mtDNA-like sequences as a close relative of mtDNA sequences, and grouped 10 closely related mtDNA-like sequences as a more basal clade, closer to ancestral states and to M. sutor. This result supports that this nuclear family of pseudogenes arose independently of the other events and may represent mitochondrial haplotypes sampled from M. galloprovincialis ancestral populations. This is the first time that Numts are proved for a longhorned beetle, whereas no Numts were found within its sister species M. sutor. The incorporation mechanism of Numts in unknown for M. galloprovincialis, however, excess of ambiguous sites corresponding to synonymous mutations placed on third codon position as well as the absence of Numts in M. sutor, conducted to the hypothesis of a recent transfer of these Numts in the nuclear genome of M. galloprovincialis. [ABSTRACT FROM AUTHOR]