Rasberry ants have invaded Houston homes, eating electrical wires and destroying computers.

Also known as crazy ants for moving in various directions instead of marching in an orderly line like other ants, the hairy reddish-brown insects usually start entering homes in May and remain there to cause havoc until September.

The ants were named after Tom Rasberry, who first saw the ants in 2002 in the Houston suburb of Pasadena and tried to exterminate the creatures.

Pest control chemicals are usually effective only for two to three months. After that, another round of spraying is required.

Ants killed by the chemicals become walk-over zones for live ones. Rasberry recounted to the Houston Chronicle he sprayed a half-acre of land with insecticide, only to discover after a few months more insects walking over two inches of dead ants.

While they do not bite, the Rasberry ants love to live in electric equipment, and in so doing, damage expensive items.

Jason Meyer, a Texas A and M University doctoral candidate who studied the ants, said the insects have already entered NASA grounds and a Houston middle school near Hobby Airport.

The ants' scientific name is paratrenicha species near pubens.