A Gregarine Parasite of Aedes hendersoni in Colorado

Date of Award


Degree Type


Degree Name

Master of Science in Biology



Chief Instructor

Todd P. Livdahl

Second Reader

David S. Hibbett

Third Reader

John S. Soghigian


Aedes hendersoni and Ae. triseriatus are closely related species of mosquitoes that are sympatric in most of their range. Previous studies have shown that Ascogregarina barretti, a gregarine parasite of Ae. triseriatus that can infect both species, may modify the competitive interaction between them by disproportionately harming Ae. hendersoni, giving Ae. triseriatus an advantage. It has also been suggested that Ae. hendersoni may have its own species of gregarine parasite, but little is known about this species. In this study, a gregarine parasite was isolated from Ae. hendersoni in an area where Ae. triseriatus does not occur. Morphological examination, phylogenetic analysis, and an experimental cross infection were conducted to learn about this gregarine and determine if it is distinct from A. barretti. A small but significant size difference, strongly supported phylogenetic distinction, and inability for this parasite to infect Ae. triseriatus were found, suggesting that it is a distinct species.