Discipline: Biological Sciences
Room: Exhibit Hall A
Lois Mack Morrow - Harris-Stowe State University
Co-Author(s): Katie Westby, Lexie Beckerman, and Kim A. Medley, Tyson Research Center, Washington University, St. Louis Mo
Vector-borne disease is an ongoing and pervasive threat to people across the globe. To date, methods to control mosquitoes have largely included chemical or bacterial interventions that cause mortality, but with unintended negative ecological consequences. Here, we investigated the ability of a widely available ornamental plant to control populations of the invasive Asian tiger mosquito, Aedes albopictus, a vector for numerous pathogens (Zika, chikungunya, and dengue viruses). Previous work has shown that mint oil can result in complete mortality of larvae in aquatic habitats, but little is known about how the plant itself could interfere with the completion of the mosquito life cycle. We tested three questions: 1) does the presence of mint plants near suitable larval habitat influence ovisposition rate? 2) does the presence of mint leaves in aquatic habitats influence oviposition rate? 3) does mint in larval habitat act as a suitable larvacide? To assess the role of mint plants in affecting oviposition decisions, we set up oviposition cups in multiple locations in urban yards and paired the cups with either real or fake mint plants. Over the course of three weeks, we collected eggs daily in each cup using removable oviposition papers. We predicted that fewer eggs would be laid in cups surrounded by real mint because the plant would signal unfavorable conditions for the development of offspring to the adult female mosquitoes.To examine whether mint in the water where larvae develop, or mint infusion, influence adult oviposition decisions, we set up cups containing either oak leaf infusion or mint infusion into a suburban back yard and measured differences in numbers of eggs laid over a period of three weeks. We predicted that fewer eggs would be laid in cups of mint infused water opposed to the oak infused water, in which would lower the population. Finally, we tested whether mint infusion results in higher larval mortality than oak leaf infusion. We hatched Ae. albopictus eggs in individuals vials containing either mint infusion or oak leaf infusion and recorded their developmental stage and any mortality daily over the course of three weeks. We predicted that mint infused water would be toxic to the larvae and would result in mortality. This would eliminate the larvae before they emerge into adults. Results and discussion of findings: We detected no significant difference in the number of eggs laid near live or artificial mint planst (Pr>F =0.9101). Simlarly, Ae. albopictus adults oviposited a similar number of eggs in mint infusion and oak leaf infusion (Pr>F=0.3854). However, significantly more larvae died in the mint infusion compared to the oak leaf infusion with mint having a 0.05% proportion alive vs oak having 0.35% alive. Conclusions, future research, and key references: We concluded that the present of mint plant either as live plants or in infusion has no effect on oviposition, but mint infusion does act as a larvicide. For future research we will investigate exactly how mint infusion is killing the mosquito larvae.
Funder Acknowledgement(s): Tyson Research Center at Washington University in St. Louis Mo, Missouri Louis Stokes Alliance for Minority (MoLSAMP)
Faculty Advisor: Dr. Katie Westby, Kwestby@wustl.edu
Role: I set up the experiment, potted the plants, counted the mosquito eggs, created infusions, and collected data.