Invasion of Crazy Ants Maddening For Southern U.S.

A maddening invasion of "crazy ants" has people in Texas and other states in the South wishing for the old days of fire ant invasions.

Crazy ants get their name from their erratic behavior, darting in nonsensical zig-zags and straying far from colonies, getting into walls of homes and short-circuiting electrical equipment as they congregate en mass, sometimes causing thousands of dollars in damage.

Crazy ants are so invasive that in some areas they have become the ecologically dominant species of ant and arthropod, creating supercolonies that drive other, less crazy, ants out.

"When you talk to folks who live in the invaded areas, they tell you they want their fire ants back," said Ed LeBrun, a researcher at University of Texas, Austin. "Fire ants are in many ways very polite. They live in your yard. They form mounds and stay there, and they only interact with you if you step on their mound."

Native to Argentina and Brazil, crazy ants, sometimes referred to as Raspberry crazy ants or tawny crazy ants, are formally known as Nylanderia fulva and were spotted in the Houston area in 2002. The ants have since spread throughout portions of the Southern U.S., invading much of Texas and along through the Gulf region and into Florida.

In their native lands, crazy ant populations are kept under control by a natural system of checks and balances; there are species that prey on the crazy ants and they face competition from other ant species.

But in America, the crazy ants are reining supreme, having no competition from other ant populations and few natural enemies, LaBrun said.

Controlling crazy ant populations is difficult because, unlike fire ants, the crazy ants don't consume most of the poisonous baits that are used to eliminate fire ant mounds, LeBrun said.

"They don't sting like fire ants do, but aside from that they are much bigger pests," LeBrun said. "There are videos on YouTube of people sweeping out dustpans full of these ants from their bathroom. You have to call pest control operators every three or four months just to keep the infestation under control. It's very expensive."

Crazy ants can thrive in a variety of unusual places and their populations can easily spread with the aid of humans, who can inadvertently transport the ants as we move about. Left to their own devices, the crazy ants can only move about 650 feet (200 meters) a year, so for the ants to colonize new areas they must hitch a ride with more prolific travelers.

LeBrun said if people actively avoid any accidental transportation of the ants, it could slow the spread of their population enough that the ecosystems will have time to adapt and researchers the time to develop better methods to control the invasive ants.