Scaling Value as a Potential Morphological Proxy for Human Biting Preference in Aedes aegypti

Abstract

Aedes aegypti is a renowned deadly vector for arboviral diseases such as yellow fever, dengue fever, chikungunya and Zika virus. Research suggests that there may be morphological characteristics that are linked to vector competence and biting behavior. Previous studies show a relationship between abdominal scaling coloration and host preference in the globally invasive subspecies Aedes aegypti aegypti in Northern Senegal and Thailand. This project aims to quantify the correlation between scaling value (observed white scales on the first abdominal tergite) and biting preference in mosquito populations from 12 locations across the Sub-Saharan region of the West Sahel, where it is believed that divergence between the ancestral generalist subspecies (Aedes aegypti formosus) and the invasive human specialist subspecies (Aedes aegypti aegypti) originated. Through microscopy and image analysis I was able to quantify white scaling on the first abdominal tergite of 120 female invasive individuals. Statistical analysis shows significance in the differences in means between the populations, as well as a robust relationship between scaling coloration and biting behavior. Individuals with more white scales tend to prefer to bite humans. Populations differ in level of white scaling and average preference for humans. Results indicate that scaling value or observed scaling score is an effective proxy for host preference in Aedes aegypti and has broader implications about using scaling as an effective and inexpensive tool to monitor and characterize local mosquito populations.