Date of Award

January 2022

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biology

First Advisor

Rebecca B. Simmons

Abstract

The tribe Noctuini comprise over 520 species; many are economically important species that impact human agriculture. Despite their diversity and relevance, relationships of the Noctuini have been difficult to resolve. There are extensive morphological revisions of these taxa (e.g., Agrotis, Euxoa); however, there are no studies that focus exclusively on the phylogenetic relationships of the Noctuini. Currently, the Noctuini are separated into two subtribes, the Agrotina and Noctuina, which each are further subdivided into two subgenera. In this study, we tested previous classification schemes using three loci. We sampled three outgroup taxa and 54 noctuine species that represent the majority of genera within the tribe. Using museum specimens, we collected data from cytochrome oxidase I (COI), Dopa Decarboxylase (DDC), and Elongation factor 1-α (EF1-α) to generate a 1378 base pair dataset. We found equivocal support for reciprocally monophyletic Agrotina and Noctuina. We found strong support for smaller, well-described genera (e.g., Spaelotis), but poor support for large genera such as Euxoa, Feltia, and Agrotis. It is likely that a combination of limited taxon sampling and the rapid evolution of these species resulted in a lack of phylogenetic resolution in the resulting topologies. We recommend increased taxon sampling and inclusion of loci that target these rapidly evolving lineages to achieve a better understanding of the phylogeny of the Noctuini and relationships of its genera. Members of Euchromiina and Ctenuchina are known for their ability to mimic other organisms and for their aposematism. Their overall appearance signals predators of their unpalatability due to larval sequestration of plant secondary chemicals; these moths are often members of Müllerian mimicry rings with other noxious insects. Because mimetic traits can be due convergence on common model species, evolutionary relationships within euchromiines are obscured, impeding an understanding of how mimetic traits were acquired in this lineage. Wing patterns represent a suite of traits that are instrumental to euchromiine mimicry. Wings can be hyaline (=clear), partially scaled, and scaled. Tiger moth wings display wing pattern elements that enhance their resemblance to other members of their mimicry rings. This research focuses on the following wing elements, Basalis (B), Discalis I (DI), Discalis II (DII), Externae patterns (E), and Apical spots. A phylogeny of 81 species (50 genera) was constructed using seven molecular markers (~ 3100 bp) with model-based approaches. Ancestral state reconstruction was assessed with Mesquite using stochastic models. Results indicate that the Euchromiina and Ctenuchina are monophyletic with respect to each other; with a misplaced ctenuchine genus Abrochia. Wing patterns do not appear to be conserved throughout the mimetic tiger moth lineage; indicating independent evolutionary events that converge on common phenotypes. The results of this research can lead to a better understanding of how Müllerian mimicry has evolved in mimetic tiger moths, allowing for further study of this system.

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