Insects, rodents invade homes as the weather turns cool

By Adrian Higgins
Thursday, November 5, 2009; T11

In the quiet of my home office, my thoughts are sometimes interrupted by the patter of paws. The unseen creature tears along the attic flooring above. I take it for a squirrel but will never find out, because when this part of the house was built, the contractor failed to provide any human access to the rear attic.

Animals find shelter in our homes, unnerving millions of people and generating a multibillion-dollar pest control industry. Intelligent life forms know a good thing when they see it. If I were a squirrel, I'd go for an attic rather than a leafy nest high in a cold, swaying tree. In my corner of the metropolis, where caves are scarce, bats also are drawn to attics. So are starlings and sparrows. One learns to live with them.

What is less tolerable to most people is the arrival of creepy crawlies. This is something to ponder, because at this time of year we are faced with home invasions by two insects that were unknown to previous generations of Washingtonians.

If you see ladybugs swarming on a bright exterior wall of your home, know that they are trying to find a portal inside, where they will collect in wall cavities or rooms. They emit an acrid and staining yellow dye if disturbed. This is an imported insect, the multicolored Asian lady beetle; it thinks your home is a limestone cliff somewhere in Japan and a grand place to spend the winter. It is otherwise a highly beneficial garden insect, devouring aphids, but it gets lonely in autumn.

A more recent fall invader is a true bug, a shieldlike creature called the brown marmorated stink bug. Marmorated means marbled, but there is nothing inert about the pest, which emits an odor when disturbed and is a pest in the garden, feeding on fruit and vegetables.

Standard advice for both is to make sure cracks and crevices are sealed and attic vents netted to stop their entry, and to vacuum them if they enter the house. Throw out the bag afterward.

Whitney Cranshaw, an entomologist at Colorado State University, has just completed a national survey of fellow experts to determine which creatures bug homeowners the most. He excluded spiders. The No. 1 offender on his top 10 list is an animal most people have never heard of but obviously find commonly: a tiny arthropod called a springtail. Next come box elder bugs, which can cluster in alarming numbers but are harmless. "There are few less innocuous life forms," says Cranshaw. "If you can get that across, people are okay with it, if they understand it's not a cockroach, it's not attacking the woolens and it's not something that might bite them."

The house-proud equate the presence of insects with the stigma of keeping an unclean domicile. "Everybody can have box elder bugs," says Cranshaw, and the same goes for a black fly that appears out of the blue, and often in groups, in the winter. About the size of a house fly, the cluster fly buzzes about the room bumping into mirrors and things. "They can be huge in terms of numbers, but this is not a filth fly," Cranshaw says. It preys on earthworms in the garden but is drawn to buildings when the weather turns cold. I catch them with a butterfly net and release them outside. They probably fly straight back into the house.

Cranshaw believes that a top 10 list a decade from now will place the brown marmorated stink bug as the primary home invader.

As we ponder what to do about the stink bug, we should be thankful we have been spared (so far) the invasion of an exotic ant species named the Rasberry crazy ant, named after the exterminator who found it and for its erratic movement. Believed to have arrived in a cargo ship, the small and reddish creature has spread across several Texas counties from Houston and likes to swarm into houses. Its colonies are large and on the march. Most alarming, it has a penchant for invading and messing up computers and other electronic equipment.

"It comes into houses and drives people crazy, maybe suppressing housing values," says Cranshaw.

In his neck of the woods, an occasional plague of moths disrupts human life as the miller moth flies from lower elevations for summer feeding in the mountains.

"There are so many people who are paralyzed by moths. If there's a moth in the house it's worse than a spider for them, worse than a snake." Worse, even, than a rodent in the roof.

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