Abstract

Coleoptera is currently the most diverse lineage of life on Earth with more than 400,000 described species. The group also contains unbelievable ecological and morphological variation that has been evolving since the early Carboniferous (>350 MYA). The group provides the perfect playground to test evolutionary hypotheses with large-scale phylogenies. First, a newly developed bioinformatics tool is presented that allows for the critical assessment of the stability of phylogenetic nodes with even minor changes in taxon sampling (i.e. a single taxon jackknifed). The tool, TANOS, is capable of performing tests on large genomics-scale datasets. The case study included is a widely used phylogenomics effort to resolve the higher level relationships of all Insecta. The specific beetle group chosen for the remaining products is the superfamily Cucujoidea, and more specifically the family Nitidulidae, or sap beetles. Several taxonomic and nomenclatural projects were necessary to provide a more stable classification and begin the process of establishing the group as a model system for questions concerning feeding behavior evolution. Several new species of the genus Carpophilus were described from both the West Indies and the New World tropics and subtropics. Several type designations were also needed for many species in the subfamily Carpophilinae. In addition, the fossil diversity of Nitidulidae was reviewed with the addition of the oldest known member of the Cillaeinae from amber (Dominican). With the reviewed fossil fauna, as well as many more from across the Cucujoidea more broadly, a divergence-time estimated phylogeny was generated for >250 species of the superfamily. The phylogeny, based on the combination of multiple published Sanger datasets and supplemented with newly generated data for a further 50 species, was used to date multiple feeding shifts in the group. Specifically, the clade ages were used to compare with published clade ages for the corresponding food resource each clade is known to exploit. A significant relationship was recovered between age of the beetle clade and the corresponding food resource clade. Interestingly, it was found that clades that shifted to a food resource first, in the absence of existing beetle competitors, were significantly more diverse over subsequent lineages that shifted to the same resource. A feeding ecology of specific importance, at least to many groups of nitidulid, is anthophily, or flower-visiting. An extreme variation in eye size is observable across the family and so multiple factors including; sex, day-night activity, and feeding behavior were tested in a phylogenetic context. No sexual dimorphism nor variation consistent with activity period was found. Relative eye size of flower visiting species was significantly larger than that of all other feeding behaviors in sap beetles. This correlation was also tested in a phylogenetic context, with the increase in morphological investment in vision repeatedly shown to correspond to shifts in flower associated behavior. In an attempt to investigate the interplay between behavior, morphology, and genetics in the same process, opsin data was captured as part of a large targeted enrichment sequencing effort (AHE) across Nitidulidae and their relatives. The first phylogenomic estimate was generated for the group, with a taxon sampling of 192, and data sampling depth of 703 loci. A newly updated pipeline was developed for AHE data and is presented herein. Topological results support the recent idea of a non-monophyletic Cucujoidea. Results also demonstrate multiple classification issues within the Nitidulidae with several new subfamilies/tribes necessary to maintain diagnosable monophyletic groups in the family. The vast majority of sampled genera were supported, with the exception of Brachypeplus and Pallodes. Preliminary opsin diversity across the group is much greater than previously estimated. Opsin copy number is potentially plastic even within individual genera, although consistently duplications are associated with taxa that visit flowers. It is clear that the complexity of cucujoid visual systems increases with anthophilous behavior.

Degree

PhD

College and Department

Life Sciences; Biology

Rights

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