If you haven't noticed, they bite. They smell. They eat anything in their path. They look like evil ladybugs.

But the orange and yellow insects showing up all over campus in the past few weeks are actually multicolored Asian lady beetles, harmonia axyridis. They were brought to this country to control crop pests, but they're also bugging the heck out of humans and hurting the ecosystem.

"The beetle is ruining the reputation of native ladybugs everywhere," said May Berenbaum, professor in the entomology department at the University.

Importing the lady beetles from Asia began in the early 1900s as a biological control in the South for aphids that were destroying pecan and apple crops, said David Voegtlin, an entomologist at the Illinois Natural History Survey.

The beetles appeared in Illinois in the late 1990s. And because they have kept soybean aphids in check — an annoyance for farmers that began in in 2000 — the lady beetles were much appreciated.

However, when soybean aphids reached a high population this past summer, the lady beetles followed suit, Berenbaum said.

Now, the presence of the insects is "really an ecological disaster," Voegtlin said. The insatiable appetite of the lady beetle means that aphids aren't the only insect on the menu.

Many harmless native insect populations are also being affected, Voegtlin said.

"Harmonia has gone past just eating the bad guys and now is eating the good guys," Voegtlin said. "It's not beneficial anymore. It's a problem insect now."

The multicolored Asian lady beetle even eats its look-alike — the native ladybug, which is in danger of becoming extinct because of this predator.

"The lady beetle is such a voracious eater," Berenbaum said. "It's not just eating the pesky aphids, it'll eat anything that is soft and easy to catch."

Lady beetles stay in soybean fields for the summer, but as winter approaches, they are seeking shelter in the cracks of warm buildings and houses, Berenbaum said.

"While the soybean farmer may enjoy the lady beetles now, they will be cohabiting in the farmer's house over the winter," Berenbaum said.

And that has brought the nuisance into Champaign-Urbana. Tammy Carswell lives in Urbana and has found many lady beetles invading her house.

"We have vaulted ceilings and I find them there and in my car," Carswell said. "They're everywhere and they're just kind of gross."

Likewise, Carolyn Koegler, freshman in LAS, has had her share of encounters with the beetles. "I opened my purse the other day and there was one in there, which was creepy," Koegler said. "And they bite. They're evil."

As the days grow colder and more and more of the insects will be flying around. Voegtlin said there is at least one beetle for every soybean plant. With 100,000 plants per acre and hundreds of thousands of acres in Illinois, "there will be literally billions of these beetles in the air," Voegtlin said.

"In about a month, there will be flights like you wouldn't believe," he said.

Entomologists are still studying the beetle and its life cycle, which can last up to three years, Voegtlin said. But until more research is done, the colorful predators are here to stay.

"The lady beetles are just an annoyance to most people because they don't understand the ramifications to the natural ecosystem," Voegtlin said. "They are pretty destructive organisms in our natural system, and all we can do right now is sit back and watch."