Evolutionary Studies of Fruit-Piercing Moths in the Genus Eudocima Billberg (Lepidoptera: Erebidae)

Crystal C Klem, Purdue University

Abstract

The prevalence of monoculture and landscape simplification is correlated with diminished biodiversity and increased presence of harmful pest species in crop environments. Lepidoptera is the largest clade of herbivorous insects, with many agriculturally significant species. The pest status of insects in agricultural settings is human-defined based on behaviors that may negatively impact the yield of susceptible crops. As such, both the insect behavior and the affected crop play a part in determining pest status. One helpful means of understanding pest status involves using pest injury guilds, which distinguish different pest groups based on similar kinds of injury to comparable plant tissues. Pest injury guilds defined in the literature are reviewed and then applied to agriculturally-significant Lepidoptera. Specialized Lepidoptera behaviors are reviewed within their respective injury guilds, and the systematics, ecology, and control options for fruitpiercing moths are discussed within the context of pest Lepidoptera behaviors. To address the need for distribution information for economically relevant Lepidoptera, the first annotated checklist of pest Lepidoptera is also provided for the United States and Canada. This checklist includes 80 agriculturally significant Lepidoptera species and complexes, and incorporates notes on distribution, species delimitation, natural history, and establishment. Fruit-piercing moths in the genus Eudocima Billberg, 1820 have significant pest status as adults rather than as larvae, and directly injure fruits using a specially-adapted proboscis. There are at least 48 Eudocima species which are found in the world’s tropics, but confusion persists in the classification of this genus and there are several suspected complexes. Additionally, the area of origin for this group is uncertain, although the Oriental region has been postulated. A comprehensive phylogenetic analysis of Eudocima is conducted using 82 morphological characters, which are each described and figured, and analyzed using parsimony. Results suggest that Eudocima is not monophyletic. Strongly-resolved relationships were recovered, although these did not correspond with previous generic concepts. The Australian region is recovered as the most parsimonious area of origin for Eudocima, and patterns of dispersal, particularly between the Oriental and Australian regions along the Indo-Australian Archipelago, are discussed. The Eudocima phalonia-complex is distributed throughout the Old World and has been the subject of increasing interest and research due to its economic impact in the tropics and status as a potential invasive species. The recent description of closely-related sister species, as well as morphological variation documented within E. phalonia itself, suggests possible speciation occurring within E. phalonia populations across its wide geographic range. To test species boundaries for this taxon, a molecular phylogeny is constructed using anchored hybrid enrichment and a next-generation sequencing approach. Sampling for this phylogeny was informed using a global range map for E. phalonia, which was developed using georeferenced specimen data from natural history collections. Biogeographic analyses are also conducted to investigate the area of origin and dispersal patterns of E. phalonia, and to examine possible speciation modes and gene flow. Georeferenced range information is also utilized along with environmental variables in constructing a correlative environmental niche model using MaxEnt, which is used to evaluate a previous mini risk assessment for environmental suitability in the continental United States for E. phalonia establishment. Results suggest that E. phalonia is monophyletic, with gene flow still occurring between populations. The area of origin for E. phalonia is postulated to be the Oriental region, although further investigation is needed. Range predictions for E. phalonia from environmental modelling were performed for both the Old World, which concurred well with occurrence data, and for the New World. Assessment of environmental suitability for E. phaloniain the continental United States suggests areas in Florida and along the Gulf Coast are most favorable for establishment.

Degree

Ph.D.

Advisors

Cameron, Purdue University.

Subject Area

Morphology|Ecology|Genetics|Systematic biology

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