Plant feeding insects and the plants they feed upon represent an ecological association that is thought to be a key factor for the diversification of many plant feeding insects, through differential adaptation to different plant selective pressures. While a number of studies have investigated diversification of plant feeding insects above the species level, relatively less attention has been given to patterns of diversification within species, particularly those that also require plants for oviposition and subsequent larval development. In the case of plant feeding insects that also require plant tissues for the completion of their reproductive cycle through larval development, the divergent selective pressure not only acts on adults, but on the full life history of the insect. Here we focus attention on Rhinusa antirrhini (Curculionidae), a species of weevil broadly distributed across Europe that both feeds on, and oviposits and develops within, species of the plant genus Linaria (Plantaginaceae). Using a combination of mtDNA (COII) and nuclear DNA (EF1-alpha) sequencing and copulation experiments we assess evidence for host associated genetic differentiation within R. antirrhini. We find substantial genetic variation within this species that is best explained by ecological specialisation on different host plant taxa. This genetic differentiation is most pronounced in the mtDNA marker, with patterns of genetic variation at the nuclear marker suggesting incomplete lineage sorting and/or gene flow between different host plant forms of R. antirrhini, whose origin is estimated to date to the mid-Pliocene (3.77 Mya; 2.91-4.80 Mya).

Aim We test three alternative hypotheses for the disjunct Mediterranean–southern African distribution of endophagous weevils within the genera Rhinusa and Gymnetron (Coleoptera: Curculionidae): (1) a Palaearctic origin with dispersal to southern Africa; (2) a southern African origin with dispersal to the Palaearctic; and (3) a widespread ancestral distribution fragmented by vicariance. Divergence times are estimated to provide an approximate temporal framework for the evolution of the group and to evaluate potential palaeogeographical scenarios. Location Southern Africa, the Mediterranean region, the Palaearctic and eastern Africa. Methods Freshly collected and dry, pinned samples of weevils were used as a source of DNA. Prior genetic information was used to identify short phylogenetically informative amplicons within the 16S ribosomal RNA gene (16S). Phylogenetic reconstructions using Bayesian and maximum likelihood analyses of mitochondrial and nuclear DNA sequence data and molecular dating techniques were used to infer the biogeographical history of Rhinusa and Gymnetron species. A statistical approach to dispersal–vicariance analysis (s‐diva) was used to further assess biogeographical hypotheses. Results Successful polymerase chain reaction amplification of targeted short 16S DNA sequences (150 bp) from dry, pinned specimens provided for increased species sampling of Rhinusa and Gymnetron by 230%, greatly expanding species representation from southern Africa. Phylogenetic reconstructions and s‐diva analyses support a southern African origin for Rhinusa and Gymnetron species. Divergence time estimates suggest southern African and Palaearctic lineages diverged c. 11.6–7.4 Ma. Main conclusions Rhinusa and Gymnetron represent a complex of lineages with a shared evolutionary history of range expansions from southern Africa into the Palaearctic. Our results support a late Miocene vicariance scenario, most likely as a result of repeated desertification. The use of prior genetic information to identify short phylogenetically informative amplicons offers a useful approach for molecular phylogenetic analyses incorporating archival material.

A combined morphological, molecular and biological study shows that the weevil species presently named Mecinus janthinus is actually composed of two different cryptic species: M. janthinus Germar, 1821 and M. janthiniformis Toševski & Caldara sp.n. These species are morphologically distinguishable from each other by a few very subtle morphological characters. On the contrary, they are more readily distinguishable by both molecular and biological characters. A molecular assessment based on the mitochondrial DNA cytochrome oxidase subunit II gene revealed fixed differences between the two species with p‐distances between samples of both species ranging from 1.3 to 2.4%. In addition to this, the larvae of the two species are found to develop on different species within the genus Linaria (Plantaginaceae): M. janthinus is associated with yellow toadflax (L. vulgaris) and M. janthiniformis with broomleaf toadflax (L. genistifolia) and Dalmatian toadflax (L. dalmatica). Molecular and host use records further suggest the occurrence of a third species associated with L. vulgaris within M. janthinus, sampled from north Switzerland, central Hungary and east Serbia. The significance of these new findings is of particular importance because species of the M. janthinus group are used, or are potential candidates, for the biological control of invasive toadflaxes in North America.

Revision of Mecinus heydenii species complex (Curculionidae): integrative taxonomy reveals multiple species exhibiting host specialization. -Zoologica Scripta, 43, 34-51. A combined taxonomic, morphological, molecular and biological study revealed that the species presently named Mecinus heydenii is actually composed of five different species: M. heydenii Wencker, 1866; M. raphaelis Baviera & Caldara sp. n., M. laeviceps Tournier, 1873; M. peterharrisi To sevski & Caldara sp. n. and M. bulgaricus Angelov, 1971. These species can be distinguished from each other by a few subtle characteristics, mainly in the shape of the rostrum and body of the penis, and the colour of the integument. The first four species live on different species of Linaria plants, respectively, L. vulgaris (L.) P. Mill., L. purpurea (L.) P. Mill. L. genistifolia (L.) P. Mill. and L. dalmatica (L.) P. Mill., whereas the host plant of M. bulgaricus is still unknown. An analysis of mtCOII gene sequence data revealed high genetic divergence among these species, with uncorrected pairwise distances of 9% between M. heydenii and M. raphaelis, 11.5% between M. laeviceps, M. heydenii and M. raphaelis, while M. laeviceps and M. peterharrisi are approximately 6.3% divergent from each other. Mecinus bulgaricus exhibits even greater divergence from all these species and is more closely related to M. dorsalis Aub e, 1850. Sampled populations of M. laeviceps form three geographical subspecies: M. laeviceps laeviceps, M. laeviceps meridionalis To sevski & Jovi c and M. laeviceps corifoliae To sevski & Jovi c. These subspecies show clear genetic clustering with uncorrected mtDNA COII divergences of approximately 1.4% from each other. Corresponding author: Ivo To sevski, CABI,