Menus Subscribe Search

Predators Make Great Mosquito Repellent

• November 08, 2010 • 5:00 AM

The latest buzz in the eternal battle against mosquitoes, researchers identify a natural deterrent released by skeeters’ predators.

Quiet as they are, mosquitoes generate a lot of buzz from scientists, pharmaceutical companies, aid groups and governments trying to get rid of them and the diseases they carry, including dengue, West Nile virus and malaria.

Today, the fight against mosquitoes has never been so heated. In March, scientists announced a new way to interfere with mosquito reproduction by unlocking a sort of “chastity belt”. In July, a University of Kansas lab was able to make the bugs more susceptible to insecticides by silencing genes in larvae using nanoparticles. Also in July, a team at the University of Arizona unveiled the first “malaria-proof” mosquito. It could be another 10 years, however, before the genetically modified insect makes it out of the containment lab, the researchers say.

So until we can rid the world of mosquitoes altogether, as some scientists hope, the next best thing is to keep them away from populated areas. Published last month in Ecology Letters, researchers at the University of Haifa in Israel have identified two chemicals, released by predators, that cause female skeeters to go lay their eggs elsewhere — a potential new environmentally friendly method for mosquito control.

Ecologists have long known that some prey species detect chemicals released by predators, typically by-products of metabolic processes, and take action to avoid being eaten or having their offspring eaten. The larvae of water fleas, for example, change their shape drastically, growing pointy helmets and spines in response to a nearby predator chemical.

In temporary pools in the deserts of Israel, ecologist Leon Blaustein noticed that in the presence of backswimmers (Notonecta maculata), a small predatory water bug, mosquitoes (Culiseta longiareolata) do not lay eggs. Some chemical cue seemed to be warning the pregnant females away from those backswimmer-laden pools, Blaustein hypothesized.

So he and his team compared chemicals released by the backswimmers with those released by a mosquito predator that does not elicit an avoidance response, the emperor dragonfly (Anax imperator). Comparing the two lists, they found a handful of chemicals unique to the backswimmer, then determined which of those, if any, warned away pregnant mosquitoes.

“It was little bit like finding a pin in a haystack,” says Blaustein.

In the end, serendipity prevailed. The team isolated two compounds — n-tricosane and n-heneicosane — found in the exoskeletons of some animals and in plants. Applying a duo of the compounds, both readily available from commercial chemical manufacturers, to a pool of water prevents a female mosquito from laying her eggs there. Increased searching for a breeding site increases the likelihood that a mosquito will die before laying eggs, says Blaustein, so the technique has potential not only as a repellent, but also to help reduce mosquito populations overall in an area.

For now, however, the chemicals only repel mosquitoes from a body of water for 24 hours.

“What we have so far may be effective, but if we can find or make more longer-lasting chemicals, that would be even better,” says Blaustein. He hopes chemists may be able to tweak the chemistry of the two compounds to extend their effects.

Though the mosquito species used in the experiment is not a disease vector, the backswimmer also repels pregnant Anopheles gambii females, “the most important malaria vector in the world,” says Blaustein. He does not know yet if the same chemical repels both mosquito species, but the natural repellent technique can very likely be applied to many other disease-carrying species, says Blaustein.

“It is promising,” he says.

Subscribe to Miller-McCune

Megan Scudellari
Megan Scudellari is a freelance writer and journalist based in Durham, N.C. She has contributed to Scientific American, Earth and Nature Medicine, among other publications.

More From Megan Scudellari

A weekly roundup of the best of Pacific Standard and PSmag.com, delivered straight to your inbox.

Recent Posts

July 28 • 4:00 PM

Border Fences Make Unequal Neighbors and Enforce Social Inequality

What would it look like if you combined Israel, the West Bank, and Gaza, demographically speaking? What about the United States and Guatemala?


July 28 • 2:00 PM

Are Patient Privacy Laws Being Misused to Protect Medical Centers?

A 1996 law known as HIPAA has been cited to scold a mom taking a picture of her son in a hospital, to keep information away from police investigating a possible rape at a nursing home, and to threaten VA whistleblowers.


July 28 • 12:00 PM

Does Internet Addiction Excuse the Death of an Infant?

In Love Child, documentary filmmaker Valerie Veatch explores how virtual worlds encourage us to erase the boundary between digital and real, no matter the consequences.


July 28 • 11:11 AM

NASA Could Build Entire Spacecrafts in Space Using 3-D Printers

This year NASA will experiment with 3-D printing small objects in space. That could mark the beginning of a gravity-free manufacturing revolution.


July 28 • 10:00 AM

Hell Isn’t for Real

You may have seen pictures of the massive crater in Siberia. It unfortunately—or fortunately—does not lead to the netherworld.


July 28 • 8:00 AM

Why Isn’t Obama More Popular?

It takes a while for people to notice that things are going well, particularly when they’ve been bad for so long.


July 28 • 7:45 AM

The Most Popular Ways to Share Good and Bad Personal News

Researchers rank the popularity of all of the different methods we have for telling people about our lives, from Facebook to face-to-face.


July 28 • 6:00 AM

Hams Without Ends and Cats Tied to Trees: How We Create Traditions With Dubious Origins

Does it really matter if the reason for why you give money to newlyweds is based on a skewed version of a story your parents once told you?


July 28 • 4:00 AM

A Belief in ‘Oneness’ Is Equated With Pro-Environment Behavior

New research finds a link between concern for the environment and belief in the concept of universal interconnectedness.


July 25 • 4:00 PM

Flying Blind: The View From 30,000 Feet Puts Everything in Perspective

Next time you find yourself in an airplane, consider keeping your phone turned off and the window open.


July 25 • 2:00 PM

Trophy Scarves: Race, Gender, and the Woman-as-Prop Trope

Social inequality unapologetically laid bare.


July 25 • 1:51 PM

Confusing Population Change With Migration

A lot of population change is baked into a region from migration that happened decades ago.


July 25 • 1:37 PM

Do Not Tell Your Kids That Eating Vegetables Will Make Them Stronger

Instead, hand them over in silence. Or, market them as the most delicious snack known to mankind.



July 25 • 11:07 AM

The West’s Groundwater Is Being Sucked Dry

Scientists were stunned to discover just how much groundwater has been lost from beneath the Colorado River over the past 10 years.


July 25 • 10:00 AM

Shelf Help: New Book Reviews in 100 Words or Less

What you need to know about Bad Feminist, XL Love, and The Birth of Korean Cool.



July 25 • 8:00 AM

The Consequences of Curing Childhood Cancer

The majority of American children with cancer will be cured, but it may leave them unable to have children of their own. Should preserving fertility in cancer survivors be a research priority?


July 25 • 6:00 AM

Men Find Caring, Understanding Responses Sexy. Women, Not So Much

For women looking to attract a man, there are advantages to being a caring conversationalist. But new research finds it doesn’t work the other way around.


July 25 • 4:00 AM

Arizona’s Double-Talk on Execution and Torture

The state is certain that Joseph Wood’s death was totally constitutional. But they’re looking into it.


July 24 • 4:00 PM

Overweight Americans Have the Lowest Risk of Premature Death

Why do we use the term “normal weight” when talking about BMI? What’s presented as normal certainly isn’t the norm, and it may not even be what’s most healthy.


July 24 • 2:00 PM

California’s Lax Policing of the Fracking Industry Has Put the Drought-Stricken State in a Terrible Situation

The state’s drought has forced farmers to rely on groundwater, even as aquifers have been intentionally polluted due to exemptions for the oil industry.


July 24 • 12:00 PM

What’s in a Name? The Problem With Washington’s Football Team

A senior advisor to the National Congress of American Indians once threw an embarrassing themed party that involved headdresses. He regrets that costume now, but knows his experience is one many others can relate to.


July 24 • 11:00 AM

How Wildlife Declines Are Leading to Slavery and Terrorism

As wildlife numbers dwindle, wildlife crimes are rising—and that’s fueling a raft of heinous crimes committed against humans.


July 24 • 10:58 AM

How the Supremes Pick Their Cases—and Why Obamacare Is Safe for Now

The opponents of Obamacare who went one for two in circuit court rulings earlier this week are unlikely to see their cases reach the Supreme Court.


Follow us


Subscribe Now

NASA Could Build Entire Spacecrafts in Space Using 3-D Printers

This year NASA will experiment with 3-D printing small objects in space. That could mark the beginning of a gravity-free manufacturing revolution.

The Most Popular Ways to Share Good and Bad Personal News

Researchers rank the popularity of all of the different methods we have for telling people about our lives, from Facebook to face-to-face.

Do Not Tell Your Kids That Eating Vegetables Will Make Them Stronger

Instead, hand them over in silence. Or, market them as the most delicious snack known to mankind.

The West’s Groundwater Is Being Sucked Dry

Scientists were stunned to discover just how much groundwater has been lost from beneath the Colorado River over the past 10 years.

How Wildlife Declines Are Leading to Slavery and Terrorism

As wildlife numbers dwindle, wildlife crimes are rising—and that's fueling a raft of heinous crimes committed against humans.

The Big One

One in two full-time American fast-food workers' families are enrolled in public assistance programs, at a cost of $7 billion per year. July/August 2014

Copyright © 2014 by Pacific Standard and The Miller-McCune Center for Research, Media, and Public Policy. All Rights Reserved.