Voracious swarming ants that apparently arrived in Texas aboard a cargo ship are invading homes and yards across the Houston area.

DAVID J. PHILLIP/The Associated Press

Crazy rasberry ants crawl on the hand of the exterminator they are named after - Tom Rasberry.

CRAZY RASBERRY ANTS

The small, hairy, reddish-brown creatures are known by that name: "crazy," because they wander erratically instead of marching in lines, and "rasberry" after Tom Rasberry, an exterminator who battled them early on. They're formally known as "paratrenicha species near pubens."

SPREADING

The ants, first spotted in Texas in 2002, have spread to five Houston-area counties – Harris, Brazoria, Galveston, Montgomery and Wharton. Scientists are not sure where the ants came from, but their cousins, commonly called crazy ants, are found in the Southeast and the Caribbean.

GOOD NEWS, BAD NEWS

They eat fire ants, but they also like plants, feed on such beneficial insects as ladybugs and eat the hatchlings of the Attwater prairie chicken. They bite humans, though not with a stinger like fire ants.

ELECTRICAL DAMAGE

They are attracted to electrical equipment. Scientists don't know why. The ants have ruined pumps, fouled computers and caused fire alarms to malfunction.

NO CONTROLS

Exterminators say the ants – which are starting to emerge by the billions – appear to be resistant to over-the-counter ant killers.

RESEARCH

The Texas Department of Agriculture is working with Texas A&M researchers and the EPA on how to stop the ants.

The Associated Press