A phylogeny for the Curculionidae: an integrated molecular approach to utilise the biodiversity of museums.

Curculionoidea (weevils) are one of the phylogenetically least well understood of the major beetle lineages. This is despite the fact that weevils probably represent the fastest radiation of living things on Earth, with some 62,000 species and 5,800 genera that have arisen almost exclusively in the past 65 M years. They constitute a major plant feeding radiation, but for a group of great economic importance we really know very little about the relationships among them, and the drivers of this incredible diversification. This studentship will address this gap in our knowledge by a molecular phylogenetic assessment of weevils. The bulk of weevil species are in the vast family Curculionidae and this high diversity has traditionally been explained by a cascade of evolutionary innovations that have enhanced weevil speciation rates by allowing colonisation of various new evolutionary niches and promoting high lineage survival rates, including the original shift to, and co-diversification with, angiosperms. This perspective however is too coarse, as many niche shifts occur within sublineages (including many gymnosperm-angiospem shifts). Any test of trait shifts therefore has to be performed on a tip-level, densely sampled phylogenetic tree. This, however, is complicated by the poor state of knowledge of monophyletic groups at the subfamily and tribal level which is a prerequisite for such studies. The proposed project therefore will represent a new approach to this problem, and avoid species counts and summary assignments of ecological traits to lineages whose monophyly is simply assumed (but as we now know most certainly incorrect). However, sampling at the density required will need representatives of very many groups, usually at genus level (genus monophyly is not tested here but may be equally problematic), with a selection of taxa according to taxonomic catalogues. This approach obviously requires access to a range of well identified samples, as are available in museum collections. The project will adopt a 2-step protocol to obtain a high-density phylogenetic tree. First, freshly caught, DNA-ready specimens will be used for a multi-locus phylogeny of the Curculionidae, employing standard markers successful at this level (rRNA genes, mtDNA). Second, the NHM pinned collection will be used to source critical specimens to sample type genera (to enable formal statements about taxonomic groups), selections of species within higher groups to assess their monophyly, and obtaining sufficient numbers of taxa to support node balance analysis The student will work with the exceptional ethanol and frozen Curculionoidea collections of the CASE partner. During a 12 month period at the NHM the student will utilise the expertise of the CASE partner to learn the bioinformatics tools necessary for the project, develop additional molecular markers for phylogenetic analysis, and undertake a large element of the DNA sequencing (objectives 1 and 2). During this time the co-supervisor Lyal will provide the student with fundamental training in weevil taxonomy. The student will utilise the comparatively rich fossil record for the weevils to calibrate the tree (objective 3) and will test the significance of hypothesised key evolutionary innovations (objective 4) by calculating the probabilities of observing greater or equal imbalance in species number at each node under an equal rates model. The student will also develop mini barcode primers for a hierarchical approach to the phylogenetic placement taxa that are only available within the museum dried collection (objective 5).