The Evolution of Human-Biting Preference in Mosquitoes
Department of Biological Sciences
University of Delaware
The Aedes aegypti mosquito is the major vector for transmission of numerous viral diseases, including yellow fever, dengue, and now, Zika. Interestingly, different subspecies of A. aegypti are known to exist in close proximity but with considerable genetic divergence between them. One major difference between a "forest" form and a "domestic" form is a strong preference in the latter subspecies for human over non-human blood biting. This difference was explored with genetic and neurophysiological approaches by a research group at Rockefeller University and published in a 2014 paper in Nature. This flipped case study uses parts of the Nature paper to focus on elements of the scientific method as well as evolutionary questions raised by the difference in biting preference between the two subspecies. Students prepare for class by watching a video that provides background information about the published study that forms the basis for the case. In class students then work in groups to develop a hypothesis, predictions and proposed experiments to test the idea of different biting preferences.
- Develop a hypothesis based on observations.
- Distinguish between a hypothesis and a prediction.
- Understand the defining criteria of the biological species concept.
- Connect the ideas of genetic variation between populations, subspecies, and speciation.
- Use cartooning to illustrate a set of experiments and methods from a primary research article.
- Interpret data and understand the use of measures of variance (e.g., SEM) from published figures.
- Critically analyze an experimental result and identify potential pitfalls or sources of ambiguity in an experiment.
- Understand how to design experiments to test a hypothesis.
KeywordsAedes aegypti; A. aegypti; mosquito; evolution; human biting preference; biological species concept; scientific method; speciation; genetics;
Educational LevelUndergraduate lower division, Undergraduate upper division
Type MethodsAnalysis/Issues, Journal Article, Directed, Discussion, Interrupted, Flipped
Subject HeadingsBiology (General) | Evolutionary Biology |
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The following video(s) are recommended for use in association with this case study.
- Is Human-Biting Preference an Evolved Trait in Mosquitoes?
This video begins with a historical description of the building of the Panama Canal as a “hook” to get students to understand the importance of learning more about the basic biology of mosquitoes in order to deal with problems of mosquito-borne diseases. It then provides background information about the published study that is the basis for the case. Running time: 9:32 min. Created by Gary Laverty for the National Center for Case Study Teaching in Science, 2016.
- Mosquito Life Cycle
This video documents the four stages of development in the life of Culex mosquitoes. Running time: 4:15 min. Ilse Knatz Ortabasi, 2007.
- Malaria: Human Host
Although this video describes the life cycle of the malaria mosquito (versus yellow fever), it nevertheless provides a good introduction to the role of mosquitoes as vectors of human disease. Running time: 4:18 min. Produced by HHMI BioInteractive.