One of the world's most universally loathed creatures might be living right under your bed.

It's not a monster; it's a cockroach, and though you might not realize it, you are sharing your campus and possibly your personal living space with them.

The two types of cockroaches that are most common on and around campus are American cockroaches and German cockroaches, assistant entomology professor Glenn Holbrook said.

American cockroaches are larger than their German relatives, but are usually found outdoors or underground in sewers and steam pipes, while German cockroaches live indoors, he said.

"The German cockroach never lives outside because it lives off human beings," he said.

"It is usually found in kitchens or near food-handling facilities."

Although American cockroaches sometimes get into buildings from outside, the roaches found in dorms, apartments and houses are most likely German cockroaches, Holbrook said.

He said people often bring the pests into their homes unknowingly in boxes and other containers.

"They often live in the corrugations of cardboard boxes because they like to have contact with many surfaces at a time," Holbrook said.

This is especially common during the first few weeks of the semester, after students move their belongings into their rooms, said Chad Hanning, assistant director of housing for South, Pollock, and Nittany Halls.

"We've had a couple of complaints so far," he said.

Several South Halls residents said they have already seen cockroaches in their rooms.

Roommates Alicia Carbone (junior-microbiology) and Marie Conteh (junior-biobehavioral health) said they walked into their room on their second day back at Penn State and found a large insect in the middle of the floor.

However, they said they were not sure that it was a cockroach.

"We killed it and then called Housing, who told us not to throw it away, but we had already gotten rid of it," Carbone said. Hanning said if they had saved the bug, it could have been identified properly.

"Sometimes a student will identify [a bug] as a roach when it's not," he said.

Carbone and Conteh, who lived in the same room last year as they do now, said they also found a cockroach in the hallway right outside their door at the beginning of last year.

"We couldn't believe it, because we had just come to South after living in East Halls for a year, and we had never seen one in East," Conteh said.

Erin Hagarty (sophomore-art) said she found a sizeable cockroach -- about two and a half inches long -- in her room after she returned from class one morning a couple of weeks ago.

"It was on its back, and I didn't know if it was alive, so I blew on it, and it moved," she said.

"Then I smashed it with my sandal and I screamed so I wouldn't have to hear it crunch."

But Hanning said that stepping on the insects is the one thing that people should not do.

"Cockroaches carry eggs, which will get on your shoe, and then you'll just spread them around," he said.

He said students should notify their Office of Housing and Food Services Operations when they notice any kind of pest problem, and that the office's pest control service will respond within 24 hours.

Clara Rimmer (sophomore-political science), Hagarty's roommate, said a maintenance worker came to their room after Hagarty posted a cockroach complaint on the hall's service request board.

Rimmer said the worker did not do anything because the dead bug had already been discarded and they had not seen any others.

But Hagarty is still worried.

"Where there's one [cockroach], there's many," she said.

Hagarty said she had considered using a pesticide spray but was unsure if that would violate any Housing rules.

But experts say there are more effective methods of getting rid of cockroaches.

"If you have an exploded population, baits are the most popular because you don't have to spray a pesticide all over. Plus, they are safe and effective," Holbrook said.

He explained that the bait is mixed with a pesticide or toxic compound, and the cockroach may take the bait back to its colony. Then, if it lives long enough, it may defecate, and the toxic fecal pellets are often eaten by newborns since they are not big enough to find their own sources of nutrients.

Holbrook added that cockroach baits can be bought at most drug stores for a few dollars.

Another effective method of eliminating cockroaches is boron, or boric acid, he said.

"Boric acid has been used for cockroach control in the U.S. for almost 200 years," he said.

Holbrook explained that it comes in a powder form that, when used properly, is spread around the edges of the room, where roaches will most likely come in contact with it.

"Since roaches like to have contact with many surfaces, they usually walk near the walls and aggregate in tight spaces, such as between a headboard and a wall," he said.

He explained that when roaches walk through the powder, which is in crystal form, it sticks to them.

Then, not only do they bring it back to their colony, but they also ingest it when they groom themselves.

Once inside a roach's body, the boron crystals destroy the delicate gut, and the gut content leaks out into the bloodstream, killing them much like a staff infection does to a human, he said.

Holbrook added that another benefit of boric acid is its low toxicity. He said it is often used as a cleansing agent and can also be found in most drug stores.

But, even more important than exterminating cockroaches is preventing infestations in the first place.

"Sanitation and cleanliness indoors are the key," Holbrook said.

In the dorms, food is the biggest problem, especially when it is left out unsealed or when people eat and leave crumbs, he said.

"Put all food in sealed containers, like Tupperware, so it is not available [for insects]," he said.

"Also, try not to let old food build up in the garbage can."

He added that it is also important to eliminate standing water.

"Roaches need some source of water to grow and reproduce," Holbrook said.

This source can be a glass of water left out overnight, a small puddle caused by a leak, or even improperly drained water in a sink, shower stall or bathtub, he said.

"Leaving out pet food or a water bowl will attract [roaches]," he said.

People with pets must also check the animal's food supply carefully.

"Bags of dog food are sometimes loaded with roaches," Holbrook said.

"We feed the roach colonies dog food in our labs. They love it because it is full of nutrients."