Semester of Graduation

Summer 2021

Degree

Master of Science (MS)

Department

Environmental Sciences

Document Type

Thesis

Abstract

Cemetery vases represent an important container habitat for mosquito larvae. Some species, like, Aedes albopictus and Aedes aegypti, prefer container habitats, whereas others, like Culex quinquefasciatus, will opportunistically use containers. In New Orleans, these three medically important vector species (Ae. albopictus Ae. aegypti, and Cx. quinquefasciatus) co-occur, despite a demonstrated competitive advantage of Ae. albopictus to the other two. Here we test the hypothesis that canopy cover from trees could be a mediating factor in driving mosquito assemblages in New Orleans, by influencing food sources, and the microclimate experienced by mosquito larvae. Samples from seven different cemeteries were divided between open and closed canopies. Abundance for larvae was analyzed for season and canopy. Larvae, particulate organic matter (POM) filtered from vases, and leaves were analyzed for elemental concentration (%C, %N, and C:N) and stable isotopes (δ13C and δ15N) and their relationships to season and canopy. The distribution of Ae. aegypti and Ae. albopictus under open and closed canopies could be explained by rainfall and nutrient availability. Ae. aegypti was more dominant under an open canopy early in peak mosquito season (summer) but switched to closed canopy vases late in the mosquito season (autumn). The opposite trend was observed for Ae. albopictus, and Cx. quinquefasciatus was only observed outside peak mosquito season. These dynamics suggest potential patterns of habitat segregation among these species over space and time. Open canopies had a significantly higher δ13C for POM than closed canopy, whereas some significant effects concerning season and canopy existed among larvae δ13C. δ15N was consistent all year and between canopy types for both POM and larvae. Correlations in stable isotopes were found between larvae and the POM but not for larvae and leaves, suggesting that larvae are more likely feeding on POM and not directly on leaf litter. Our study helps inform the dynamics of important mosquito vectors at the larval stage, which could aid in their management for the benefit of human health.

Committee Chair

de Jesús Crespo, Rebeca

Available for download on Tuesday, April 12, 2022

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