Electronic Theses and Dissertations

Date of Award


Document Type


Degree Name

M.S. in Biological Science



First Advisor

William J. Resetarits

Second Advisor

Jason D. Hoeksema

Third Advisor

Paul K. Lago

Relational Format



Oviposition site selection is a critical reproductive behavior for egg-laying organisms that offer little to no parental care. Determining the mechanisms females use to assess sites is critical to understanding life history traits, community structure, and species interactions. Mosquitoes are excellent model organisms for studying oviposition site selection for numerous reasons: 1) a poor decision can lead to zero reproductive success, 2) females actively assess and choose among habitat patches when locating an oviposition site, 3) larvae remain in the habitat where they hatch until they metamorphose, and 4) they lay conspicuous egg rafts that allow direct assessment of oviposition. Certain mosquito species actively detect and avoid habitats with predaceous backswimmers (Heteroptera: Notonectidae), and certain species of fish, including Gambusia affinis. For my thesis I focused on mosquitoes of the genus Culex, and how they responded solely to the presence of kairomones (chemicals emitted by an organism and detected by an individual of another species; where only the receiver benefits from the cue) released by Gambusia affinis (Western mosquitofish), Lepomis cyanellus (green sunfish), and Procambarus hayi (straightedge crayfish) when locating oviposition sites. Three paired experiments (Control vs. Predator-conditioned water) were conducted, one for each predator species. A fourth experiment was conducted to determine where Culex would oviposit in the presence of positive, negative, and neutral stimuli. Oviposition choice was quantified by collecting all egg rafts laid in experimental pools. Egg rafts were hatched, raised, and identified to species. In experiment one, Culex restuans used kairomones to detect and avoid ovipositing in the presence of G. affinis. In experiment two, L. cyanellus kairomones did not deter Culex species. In experiment three, mosquitoes were attracted to pools with crayfish-conditioned water over Controls. In experiment four, presence of G. affinis within a pair reduced the number of egg rafts found in Control and Crayfish pools. When not paired with G. affinis, Control and Crayfish pools received significantly more egg rafts than G. affinis pools. Overall, kairomones alone can drive oviposition site choice in Culex restuans, and Culex perceive quality habitats as low quality when in close proximity to G. affinis pools.



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