Male Mosquitoes Don’t Want Your Blood, But They Still Find You Very Attractive

By Perran Ross, Ph.D.

This article is republished from The Conversation under a Creative Commons license. Read the original article at: https://entomologytoday.org/2021/10/12/male-mosquitoes-dont-want-blood-still-find-humans-attractive/.

The whine of the mosquito is unpleasant and often inescapable outdoors on summer evenings. Mosquitoes track you down from tens of meters away by sensing carbon dioxide in the air you breathe out. Within seconds, they home in on exposed skin and feast on your blood with an array of specialized needles.

Only female mosquitoes drink blood, which is how they spread deadly diseases like dengue fever and malaria. Male mosquitoes are harmless, mostly feeding on nectar, but our new research confirms they are just as annoying as female mosquitoes.

Our study, published in September in the Journal of Medical Entomology, dispels a common misconception that male mosquitoes avoid people. In fact, male mosquitoes from at least one common species probably like you just as much as females do—but the reason for their fondness and the way they express it are very different.

The Backyard and the Laboratory

We used a simple experiment to test if male mosquitoes from the species Aedes aegypti, which spreads dengue, seek out people. We released mosquitoes into a large arena, the size of a suburban yard, and had willing subjects sit in a chair as bait. Cameras facing the subjects filmed mosquitoes as they flew nearby. We confirmed that male mosquitoes are indeed attracted to people.

Female mosquitoes are after your blood, but male mosquitoes just want to hang out. In our experiments, male mosquitoes continuously swarmed around people but rarely landed. By contrast, female mosquitoes land, drink their fill, and then fly away to rest.

People differ in their attractiveness to female mosquitoes, and this also holds true for male mosquitoes.

Of the two participants in our study, one person was about three times as attractive as the other. The basis of this variation is not fully understood, but the mix of chemicals you emit from your skin is likely to be important.

We also tested mosquito attraction in small cages in the laboratory. In this environment, males showed no apparent interest in people, while female mosquitoes did. This is likely because male mosquitoes can’t detect some of the close-range signals that female mosquitoes can.

If They’re Not After Our Blood, What Do Male Mosquitoes Want?

Why are male mosquitoes interested in people if they can’t feed on your blood? We think it’s all about finding the females. Since female mosquitoes are often around people, male mosquitoes that have the same inclination should have greater reproductive success.

But more work is needed to understand the how and why. Almost all behavioral research so far has focused on female mosquitoes.

However, there is growing interest in releasing modified male mosquitoes to sterilize female mosquitoes, which gives our research practical applications.

So, not all mosquitoes you see are out for your blood. Some just want you as their wingman, whether you like it or not.

By Manuel Lluberas

Manuel is a public health entomologist with extensive experience in the control of insects of public health and veterinary importance obtained during the past three decades. He served twelve years as medical entomologist and medical intelligence officer for the US Navy attached to the US Marines. He has provided technical assistance on the design, implementation, evaluation, and technical capacity building on integrated vector management to private and public entities and UN agencies in sixty-three (63) countries in three (3) continents. Some of his most significant accomplishments include designing the indoor residual spraying (IRS) campaign against malaria vectors of the US President's Malaria Initiative for Sub Saharan Africa (PMI); helping the University of South Florida and The Bill & Melinda Gates Foundation develop the habitat signatures for mosquito vectors in Cambodia using spectral signatures from sub-meter pixel data obtained from 5 satellites; and conducting Entomological Monitoring and Vector Control Capacity Evaluations against Aedes aegypti (vector of Dengue, Zika and Chikungunya) for portions of Central America under projects with USAID. Significant projects include developing and implementing the mosquito population suppression strategies in Banda Aceh and Western Sumatra, Indonesia after the Tsunami of 2005; helping Haiti's Ministry of Health and Population develop mosquito control protocols in the aftermath of the earthquake of 2010; and assisting the Pan Africa Tsetse fly and Trypanosomiasis Eradication Campaign reduce sleeping sickness in parts of West Africa. Manuel has been a member of the Vector Control Working Group of WHO’s Roll Back Malaria Campaign since its inception, published over thirty technical articles on vector management, wrote a column on Malaria World for two years, contributed to the publication of WHO’s Global Plan for Insecticide Resistance Management in Malaria Vectors, and drafted the first drafts of WHO’s Operational Manual for Indoor Residual Spraying. He has presented numerous keynote addresses and lectures on integrated vector management in Spanish and English in several international congresses and meetings and provides simultaneous translation from Spanish to English for the Latin America Symposia for the American Mosquito Control Association. Manuel was twice selected as finalist for the Rear Admiral Charles S. Stevenson Award for excellence in Preventive Medicine, the top award in US Navy Medicine and was awarded the Meritorious Service Medal from the American Mosquito Control Association. He holds an FAA certification as a Remote Pilot of a small, Unmanned Aerial System (sUAS or drone) and a 25-Ton Master Captain Certificate with sailing endorsement from the US Coast Guard.

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