Term of Award

Spring 2009

Degree Name

Master of Science in Biology (M.S.)

Document Type and Release Option

Thesis (open access)

Department

Department of Biology

Committee Chair

Lorenza Beati

Committee Member 1

Lance Durden

Committee Member 2

William Irby

Abstract

Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae) is a common tick species that has a large geographic distribution from the southern regions of the United States (Texas), to the Caribbean Islands, Central, and South America. This tick is a vector of the agent of Brazilian spotted fever, an often fatal disease in South America. Throughout its geographic range, populations of A. cajennense have shown differences in ecological adaptation while feeding on a variety of hosts ranging from livestock, birds, and humans. In order to examine the taxonomic status and phylogeographic evolution of this species, we analyzed mitochondrial 12S rDNA, control region (d-loop), and cytochrome oxidase II gene sequences of A. cajennense specimens collected in eight different localities. The results showed that our samples are grouped in five strongly supported monophyletic lineages, each corresponding to geographically or ecologically distinct populations. The strong phylogenetic structure indicates that A. cajennense may actually be a species complex in need of thorough morphological reassessment.

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