Exploring the taxonomic status of the Palearctic cone weevil, Pissodes validirostris, inferred from morphometric and molecular data

Abstract The Scots pine cone weevil, Pissodes validirostris Gyll. (Coleoptera: Curculionidae) widely distributed from Europe, across to North-Eastern China, consumes the cones of Mediterranean pines, as well those of the sylvestris section. The use of multiple host pine species with limited and patchy distributions, combined with low dispersal rates, likely contributed to significant genetic and morphological variation among P. validirostris populations in its native range. P. validirostris is being considered as a biological control agent for wilding pines in the southern hemisphere and for this programme to proceed, elucidating its intraspecific variability is necessary. This study aimed to explore the phylogeography of P. validirostris in its native range in Europe using mitochondrial and nuclear genetic markers as well as morphological characters. The integrative taxonomic analysis revealed high genetic structuring in P. validirostris populations, identifying three main phylogeographic clades: Clade A (Iberian Peninsula, associated with Pinus pinaster and Pinus halepensis ), Clade B (Central Europe), and Clade C (Northern and Eastern Europe), both associated with Pinus species of the sylvestris section. The morphometric data showed that adults of the Iberic Peninsula clade were significantly larger than those of the two others. When compared to other Nearctic and Palearctic congeneric species, P. validirostris formed a monophyletic group, likely consisting of different evolutionary lineages within the sampled distribution. The findings highlight the necessity of genetic confirmation for insect taxonomy across wide distributions or multiple host trees. Clarifying whether host specificity or geography drives P. validirostris population structuring will facilitate the selection of a specific clade for wilding pine biological control.