Date of Award

8-2012

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Entomology

Advisor

Adler, Peter H

Committee Member

Morse , John C

Committee Member

McCreadie , John W

Abstract

Cryptic species are an important component of biodiversity, although most cryptic species have yet to be discovered. Cytogenetic studies of polytene chromosomes offer a unique level of resolution for detecting cryptic species in the family Simuliidae. Simulium fibrinflatum is a black fly morphospecies that is suspected to contain cryptic species because of its broad geographic range and variable pupal gill structure. Populations of Simulium fibrinflatum from the Saugahatchee River, AL; Anthony Shoals, GA; LaHave River, Nova Scotia; Westfield River, MA; Chauga River, SC; and Enoree River, SC, were sampled and cytogenetically analyzed to test for the presence of cryptic species. To ecologically characterize S. fibrinflatum a set of 9 ecological variables was measured at each site. These variables did not show differences between streams where S. fibrinflatum was found and streams where it was not found, although the sample sizes were small. Thirty chromosomal rearrangements were found in the six populations cytogenetically analyzed. A heteroband on chromosome arm IIIL was common in all populations. The Chauga River sample was highly polymorphic, with 24 chromosomal polymorphisms, whereas the Enoree River sample had three polymorphisms, two of which were also found in the Chauga River. The two polymorphisms in both populations were found in higher frequency in the Chauga River sample. Although no fixed inversions or differentiated sex chromosomes were found in any sample, the difference in number and frequency of polymorphisms between the Chauga River sample and the Enoree River sample suggests the possibility of homosequential cryptic species in S. fibrinflatum.

Included in

Entomology Commons

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