The Chemical Sensing of Disease Vector Mosquito Larvae

Undergraduate #90
Discipline: Biological Sciences
Subcategory: Ecology
Session: 1
Room: Exhibit Hall A

Kim Ha - University of Washington
Co-Author(s): Eleanor Lutz, University of Washington, Seattle WA; Jeffrey Riffell, University of Washington, Seattle WA

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Several species of mosquitoes are carriers for life-threatening diseases such as malaria, Zika and Dengue. The ability of adult mosquitoes to search for human hosts and transmit disease is affected by their size and fertility, which correlates to larval foraging behavior. However, many studies have overlooked larval behavior to focus on the search behavior of adult mosquitoes. Targeting larvae may be more effective in improving public health since the larvae are concentrated and immobile in this stage unlike adult mosquitoes. Thus, to improve current methods of disease vector management, we are interested in studying how different species of disease vector larvae navigate to chemical cues, and determining if behavioral differences exist among these disease vectors. We are also interested in identifying how the habitat and environment have influenced the search behavior of these mosquitoes. If significant behavioral differences exist, current control strategies should be modified accordingly to take these differences into consideration. We used video tracking to investigate larval behavior when foraging or avoiding a repellent substance for four different species of mosquitoes: Aedes aegypti, Aedes albopictus, Anopheles arabiensis, and Anopheles coluzzii. We expect different foraging behavior between genera and similar behavior between sub-genera because the sub-genera share similar evolutionary histories and thus, similar habitats. We found significant differences between species in many behavioral metrics such as time spent moving, foraging behavior, and repellent avoidance. Thus, these results suggest that there is more variance in mosquito larval behavior than previously known, even among disease vector mosquitoes. This suggests that altering control strategies for each species may make larval mosquito control more effective. The implications of investigating these disease vector species may lead to improved applications of larvicides by identifying the ideal location and quantity of larvicide to add to water sources to match larval foraging behavior.

Funder Acknowledgement(s): National Institute of Health, National Science Foundation, Robin Mariko Harris Award, Margo and Tom Wyckoff Award

Faculty Advisor: Jeffrey Riffell, jriffell@uw.edu

Role: For this project, I conducted the experiments for four species of mosquito larvae and analyzed their behavior towards three chemicals: water, an attractant, and a repellent. I placed the larvae into the water and collected data using video tracking. I was then tasked with analyzing the data for specific behavioral metrics using Python.