What Are Gallnippers?

Giant Mosquitoes Invade Florida!

Gallnipper.
A gallnipper. Insects Unlocked/Public domain

Sensational news headlines suggest that giant bugs called gallnippers are invading Florida. These huge mosquitoes attack people, and their bites really hurt. If you live or vacation in Florida, should you be worried? What are gallnippers, and what can you do to protect yourself from them?

Yes, Gallnippers Are Mosquitoes

Anyone who has lived in Florida for any length of time has undoubtedly heard of the dreaded gallnippers, a nickname given Psorophora ciliata long ago.

Some call them shaggy-legged gallnippers, as the adults bear feathery scales on their hind legs. The Entomological Society of America has not approved these as official common names, but these nicknames persist in folk legends and songs.

First, the facts about gallnippers. Yes, the mosquito in question – Psorophora ciliata – is an unusually large species (you can see photos of gallnippers on Bugguide). They measure a good half-inch long as adults. Psorophora ciliata does, indeed, have a reputation for being an aggressive biter with a preference for human blood (or that of larger mammals, at least). Male mosquitoes are perfectly harmless, preferring flowers to flesh when it comes time to feed. Females require a blood meal to develop their eggs, and Psorophora ciliata females inflict a surprisingly painful bite.

Gallnippers Are Native to Florida

These "giant" mosquitoes are not invading Florida; Psorophora ciliata is a native species that inhabits much of the eastern U.S. They've been in Florida (and many other states) all along.

But Psorophora ciliata is what is known as a floodwater mosquito. Psorophora ciliata eggs can survive desiccation, and remain dormant for years. Standing water left by heavy rains can, in effect, reanimate Psorophora ciliata eggs in the soil, unleashing a new generation of mosquitoes, including females thirsty for blood.

In 2012, Tropical Storm Debby (no relation) flooded Florida, enabling Psorophora ciliata to hatch in unusually high numbers. 

Like other mosquitoes, gallnipper larvae develop in water. But while most mosquito larvae scavenge on decaying plants and other floating organic matter, the gallnipper larvae actively hunt other organisms, including the larvae of other mosquito species. Some people have suggested we use the hungry, predaceous gallnipper larvae to control the other mosquitoes. Bad idea! Those well-fed gallnipper larvae will soon become gallnipper adults, looking for blood. We would essentially convert our mosquito biomass from smaller, less aggressive mosquitoes into larger, more persistent mosquitoes.

Gallnippers Don't Transmit Diseases to Humans

The good news is Psorophora ciliata isn't known to transmit any diseases of concern to people. Though specimens have tested positive for a number of viruses, including several that can infect horses, no definitive evidence has linked the bite of a gallnipper to the presence of these viral diseases in people or horses thus far.

How to Protect Yourself From Gallnippers

Gallnippers (Psorophora ciliata) are just big mosquitoes. They might require a little more DEET, or that you wear thicker clothing, but otherwise, just follow the usual tips to avoid mosquito bites.

If you live in Florida, or in any other state where gallnippers live, be sure to also follow guidelines for eliminating mosquito habitat in your yard.

Too late? You were already bitten? Yes, indeed, gallnipper bites can and will itch just the same as other mosquito bites. 

Sources:

  • Huge, aggressive mosquito may be abundant in Florida this summer, UF/IFAS expert warns, University of Florida media release. Accessed online March 11, 2013.
  • EENY-540/IN967: A mosquito Psorophora ciliata (Fabricius) (Insecta: Diptera: Culicidae), University of Florida Extension Service. Accessed online March 11, 2013.
  • Species Psorophora ciliata - Gallinipper, Bugguide.net. Accessed March 11, 2013.