A new meta-analysis indicates that the yellow fever mosquito (Aedes aegypti) travels an average distance of 106 meters in mark-release-recapture studies, a figure that could play an important role in mosquito-management efforts. (Photo by Marie Delport via iNaturalist, CC BY-NC 4.0)

By Melissa Mayer

Melissa Mayer

When it comes to comfy breeding spots, the yellow fever mosquito (Aedes aegypti) doesn’t need much. Puddle? Empty flowerpot? Spare tire? Perfect! This container-breeding mosquito thrives in urban areas where it lives close to humans—and that’s not great news when it comes to vector control.

Because the yellow fever mosquito is the primary vector of human diseases like yellow fever, dengue, chikungunya, and Zika, figuring out how far the mosquito usually travels is an important data point for managing it. In a meta-analysis published May 31 in the Journal of Medical Entomology, researchers from the University of Arizona determined an average flight distance of 106 meters and looked at how study design and other factors may influence that number.

Heidi Brown, Ph.D.

“This meta-analysis was done to try to get a handle on [flight distance] and to say a lot of people have done mark-release-recaptures under different conditions. Can we take all of that information together and get a better estimate of the flight range of this important mosquito vector?” says Heidi Brown, Ph.D., associate professor in the Epidemiology and Biostatistics Department at the University of Arizona and co-author on the study with Ph.D. student Thomas C. Moore.

During a mark-release-recapture study, researchers catch mosquitoes, dust them with a pigment, and release them back into the population. Then, they work outward from that release spot—usually in concentric circles—and recatch the marked mosquitoes using tools like sticky traps or aspirators. The distance from the point of recapture to the release site is how far the insect traveled.

To find the mean distance traveled in the meta-analysis, the team looked at 38 published studies comprising 181 individual experiments, which reported flight distances ranging from just 12 meters to more than 2,400 meters. Brown and Moore’s overall estimate of 106 meters is a bit further than the estimate determined in a previous meta-analysis (89 meters) but much shorter than the longer distances in the dataset—which is great news for vector control.

Knowing this mosquito’s flight range is helpful when designing experiments or planning vector control programs. For example, one vector control strategy is source reduction—removing those natural or artificial containers in which the yellow fever mosquito breeds. After addressing those breeding sites, scientists and vector control experts need to know how far out from the sites they should treat and monitor for mosquitoes.

“If we say here’s an area where I’ve done vector control, and I’ve knocked out the source, what this [flight distance estimate] gives us is, from that source, how far out is the mosquito potentially going? And what are the zones where I can look for mosquitoes coming from this source?” says Brown. “What we’re advocating for is that this lends itself well to some modeling work.”

Other interesting notes from the meta-analysis include the finding of no significant difference in flight distance between wet and dry climates. But the authors did find that mosquitoes released in the morning traveled about 90 meters further than those released in the evening. And mosquitoes caught indoors traveled about 66 meters further than those captured outdoors.

The team also looked at size of the study area and recommended a study area with a radius of at least 290 meters. This could be especially useful when designing those mark-release-recapture studies or when planning treatment protocols or releases of genetically modified or Wolbachia-infected mosquitoes for vector control.

The team says it would make sense to evaluate their new flight distance estimate with geospatial analysis and compare human disease cases with their proximity to mosquito habitat sites. Finding a more robust estimate for flight distance is particularly valuable as the yellow fever mosquito’s geographic distribution is expected to expand with climate change and other factors like human movement and land use changes.

Melissa Mayer is a freelance science writer based in Portland, Oregon. Email: melissa.j.mayer@gmail.com.