Degree Type

Dissertation

Date of Award

2011

Degree Name

Doctor of Philosophy

Department

Entomology

Major

Ecology and Evolutionary Biology

First Advisor

Gregory W. Courtney

Abstract

Net-winged midges (Blephariceridae) are a group of lower Diptera uniquely adapted for life in torrential streams. Within this family, the subfamily Edwardsininae is restricted to south temperate regions -- eastern Australia, southern South America, and Madagascar -- whereas the Blepharicerinae occurs in both hemispheres. The Malagasy fauna contains both subfamilies, with the Blepharicerinae represented by an undescribed member of the tribe Apistomyiini. The remaining species belong to the Edwardsinine genus Paulianina, which currently is subdivided into the subgenera Paulianina and Eupaulianina. All members of the Malagasy fauna are endemic to the island country, where their habitat is endangered due to massive deforestation. Recent examination of historical material and collection of new specimens has required that the group be fully revised. My objectives included examining the diversity of net-winged midges on the island, testing the monophyly of all Edwardsininae and various Malagasy subgroups (genera and subgenera), as well as reconstructing the evolutionary relationships of species within Paulianina and Eupaulianina.

A complete revision of the Malagasy genera Paulianina and Eupaulianina is included. Keys to adult males, pupae and larvae are provided. Both morphological and molecular characters are used to investigate relationships within the group. Molecular characters were based on a single nuclear gene and single mitochondrial gene. Cladistic analyses, using both maximum parsimony and Bayesian inference, of both data sets support monophyly of the subfamily Edwardsininae and the genus Paulianina. Relationships within Eupaulianina remain less resolved, due partly to lack of associated adult material for several species. This research increases the number of described species from eight to twenty-seven. Phylogenetic analysis provides justification elevating the subgenera Paulianina sensu stricto and Eupaulianina to generic status, while partially resolving relationships within each genus. Overall, this research provides the most thorough examination of the group to date.

I also provide an overview of the natural history of Malagasy net-winged midges and discuss primary threats to the survival of these unusual flies. Insects play a key role in aquatic ecosystems, however, little is known regarding Madagascar's aquatic insect diversity. Limited previous research suggests remarkably high levels of endemism. Ongoing, rampant deforestation is rapidly decreasing viable habitat across the island, such that several species have likely already gone extinct. Future research on these diverse and potentially sensitive bioindicators is imperative if we are to effectively preserve and manage these ecosystems in the future.

Copyright Owner

Rebecca B. Sam

Language

en

Date Available

2012-04-30

File Format

application/pdf

File Size

194 pages

Included in

Entomology Commons

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