As far as pets go, they leave something to be desired. Gnat-sized jumping dots, they do little but move toward the light and slurp sugar water.

But when Courtney Sears, a student at Osbourn Park High School, heard that Prince William County was raising Ooencyrtus kuvanae, a parasite related to the everyday wasp, to combat the dread gypsy moth, she thought it sounded like a good way to get involved in environmental action. For the county's resource-strapped Gypsy Moth Program, it also sounded like a good idea.

So the county turned over its four wasp breeding cages to the school, and now the Bio 2 classes and the ecology club at Osbourn Park are the caretakers of the insect assassination program.

"I was just kind of looking for projects," said Sears, who is the eco club's president and a recent convert to vegetarianism. "We just brought it back to the club and everyone wanted to get involved."

It is, to be sure, not a lot of work to raise the insects, mostly a matter of collecting readily available moth eggs already infected with the parasite, giving them a nice home and dispersing the progeny throughout the area. But, Sears said, "it lets you know you're doing something. You're making a difference."

Known for eating the leaves from thousands of trees in the Northeast, the gypsy moth is too well established in the region to be eradicated. But officials hope that a variety of methods, from aerial spraying to psychological warfare (strips coated with the odor of female moths that drive males crazy looking for nonexistent mates), will control the population.

Enter Ooencyrtus kuvanae. The wasp deposits its eggs into the eggs of the gypsy moth. The developing newcomer then eats its host.

Despite sharing the wasp classification with its much larger and nefarious cousin, the Ok wasp, as it is called, doesn't sting. Bonnie Fulford, a gypsy moth specialist with the county, says the insect is ideal for helping control the moth population.

Introduced as a moth parasite from its native Japan around the turn of the century, the wasp has taken well to the Northeast. Its life cycle closely follows that of its prey, and it poses no harm to the environment and minimal annoyance to humans.

Biology teacher Larry Nemerow says the project offers a firsthand way to see how small changes in the ecosystem can have large effects. "We're learning about ecology and human mistakes," he said. "This is broader than just one idea. We're teaching how things interact."

Students went to nearby Union Mill Park, scraped penny-sized brown egg masses off trees into cups and carried them back to class. Tiny black holes indicated that the eggs were already parasitized by the wasp, so all the youths had to do was spread them on trays.

The wasps hatch in wooden, footlocker-size boxes and are attracted by a light, mounted on the side of the breeder, to removable glass vials containing sugar water, their food.

Once enough wasps have collected, the tubes are removed and students take them home to release the wasps into the environment.

With students bused from Woodbridge, Dale City and Montclair, the wasps are well dispersed through much of the county.

Some have also gotten out and become part of the classroom environment. "I take a test and there are bugs all over it," said one student.