Skip to main content
Move the World.
What's the Deal with the Giant Mosquitoes after Hurricanes?
An inch-long bloodsucker on the hunt for a meal. Credit: Ben Seese/Flickr, CC BY-NC-ND

After Hurricane Florence, reports started rolling in of “giant mosquito” sightings – and bitings – throughout North Carolina. What’s going on with these mega mosquitoes that can be as big as a quarter?

As a mosquito biologist, I often get asked to identify a mosquito based upon someone’s verbal report of the little buggers. I usually do OK with an educated guess based on descriptions like “It had striped legs, and was brown” or “It looked kind of purple.”

What I have always struggled with is when someone says “It was little” or “It was pretty big.” For the most part, size is not a good identifying feature of the common mosquitoes Americans encounter close to home.

This is because you can grow relatively large mosquitoes or small ones just depending on the conditions where they grow up – what entomologists call their larval environment. If the larval environment has few other competing mosquitoes, or is rich in nutrients, or has a cool temperature, the result is larger adult mosquitoes.

You’ll see these mosquitoes coming
your way.

You’ll see these mosquitoes coming
your way. Credit: Joanna Poe/Flickr, CC BY-SA.

There are a couple of species of mosquitoes that are truly gigantic, though. If someone says they saw a big mosquito, and I follow up with “big for a mosquito, or too big to even be a mosquito?” and they say “too big to be a mosquito, but it was biting me,” then I know we truly have one of a couple species of “giant” mosquitoes.

Under normal circumstances, these giant, biting mosquitoes – known locally here in North Carolina as “gallinippers” or scientifically as Psorophora ciliata or Psorophora howardi – are quite rare. They are two of about 175 species of mosquitoes we have in the United States. Their moment in the spotlight comes after major flooding events, like we had with Hurricane Florence. These mosquitoes can be as much as three times larger than their more typical cousins.

Life stages of mosquitoes.

Life stages of mosquitoes. Credit: LadyofHats/Wikimedia Commons, CC BY

The gallinippers belong to a genus of mosquitoes that specialize in responding to floods. Females produce lots of eggs, which they spread out around areas that might flood, such as wet meadows, floodplain forests or even agricultural land. Those eggs are resistant to desiccation – that is, they aren’t damaged by dry conditions – so they can wait around for a flood the following year, forming an “egg bank.”

The eggs are fertilized as the female lays them, from sperm she’s stored during mating. In order to get the blood meals necessary to make many eggs, these mosquitoes are aggressive feeders on mammals, and maybe other vertebrates occasionally.

But evolving to a giant size doesn’t seem necessary to carry out these tasks. Indeed, many other species in this genus are not giants; they’re more typically mosquito-sized. So what separates the gallinipper?

One possibility is the fact that gallinippers, as larvae, prey on other mosquito larvae. Perhaps their size is an adaptation to consuming other floodwater mosquitoes, allowing them to more easily capture and consume smaller species? The more typical-sized mosquitoes that use floodwaters are not predators. Size may also allow them to produce many more eggs, which can also be an advantage when the floodwaters come.

Gallinippers have a painful bite that is usually well noticed by human victims, so the large numbers that emerged after Florence have received lots of attention.

While being bitten by a giant mosquito may not seem like a great thing, there are reasons to take heart. First, these mosquitoes likely get just one good blood meal in their lives, limiting their ability to transmit a pathogen.

As far as entomologists know, they don’t transmit any pathogens to people. And since, as larvae, these giants eat other mosquitoes, maybe one big bite is worth 10 small ones? Finally, it’s a great post-hurricane brag to announce “I got bit by a giant freakin’ mosquito!”

Other good news is that the adults likely don’t live more than a couple of weeks, so the great boom of mosquitoes from Florence is winding down. Of course, now it looks like Hurricane Michael may bring about another round of gallinippers. Winter does end the most immediate threat, but all those eggs are still out there, awaiting next year’s floodwaters. The Conversation

Michael Reiskind is an Assistant Professor of Entomology at North Carolina State University. This article was originally published at The Conversation.

Up Next

VR For Good
Can VR Help Formerly Incarcerated Individuals Return to the Job Force?
project overcome
VR For Good
Can VR Help Formerly Incarcerated Individuals Return to the Job Force?
Goodwill and Accenture have teamed up to create “Project Overcome,” a VR experience that simulates the job-seeking process in hopes of curtailing recidivism.

Goodwill and Accenture have teamed up to create “Project Overcome,” a VR experience that simulates the job-seeking process in hopes of curtailing recidivism.

3D Printing
This May Be The 3D-Printed Submarine of the Future
3d printed submarine
3D Printing
This May Be The 3D-Printed Submarine of the Future
Using unique construction techniques, this 3D-printed submarine may set the pace for the building of large AUVs to come.

Using unique construction techniques, this 3D-printed submarine may set the pace for the building of large AUVs to come.

The Future Explored
Robots Can Read Your P-P-P-Poker Face
emotion ai
The Future Explored
Robots Can Read Your P-P-P-Poker Face
Emotion-detecting technology could be the next frontier of personalization. But what does this mean for privacy?

Emotion-detecting technology could be the next frontier of personalization. But what does this mean for privacy?

Women's Health
Nanotech Endometriosis Treatment Could Ease Women’s Pain
Endometriosis Treatment
Women's Health
Nanotech Endometriosis Treatment Could Ease Women’s Pain
An in-development endometriosis treatment uses dye-filled nanoparticles to identify and destroy diseased tissues.

An in-development endometriosis treatment uses dye-filled nanoparticles to identify and destroy diseased tissues.

Hacking for Good
White Hat Hackers are Defending Hospitals From Rising Cyber Attacks
cyber attacks
Hacking for Good
White Hat Hackers are Defending Hospitals From Rising Cyber Attacks
Criminals are exploiting COVID-19 to launch cyber attacks. These volunteers have grouped together to fight back.

Criminals are exploiting COVID-19 to launch cyber attacks. These volunteers have grouped together to fight back.

Dispatches
Mosquitoes Are the World's Deadliest Animals. Should We Wipe Them Out?
deadliest animal - the mosquito
Dispatches
Mosquitoes Are the World's Deadliest Animals. Should We Wipe Them Out?
The world's richest and poorest people are teaming up against our deadliest predator.

The world's richest and poorest people are teaming up against our deadliest predator.

Dispatches
How Redesigning Labs Can Demystify Genetic Science
How Redesigning Labs Can Demystify Genetic Science
Dispatches
How Redesigning Labs Can Demystify Genetic Science
"Scientists work in high-security buildings that are banned to the public and then wonder why they are misunderstood."
By Brook Muller

"Scientists work in high-security buildings that are banned to the public and then wonder why they are misunderstood."

Dispatches
How a Video Game Helped the Cajun Navy Save Lives
How a Video Game Helped the Cajun Navy Save Lives
Dispatches
How a Video Game Helped the Cajun Navy Save Lives
When lives are on the line, inspiration can come from the most unlikely places.
By Brandon Stewart

When lives are on the line, inspiration can come from the most unlikely places.