LEWISTON — Professor James Dill got his first good groan of the day when he talked about the bedbug’s “piercing, sucking mouth part.”

The close-up picture on the screen behind him, illustrating the pest’s sharp proboscis, certainly added to the effect. A few people groaned; several laughed nervously.

And many began to scratch involuntarily.

“That’s the business end,” he said. “And what does it feed on?”

Nearly all 140 people attending a forum at Bates College on Friday replied, almost in unison: “Blood.”

Everyone in the room, which included health officials, social workers, landlords, health care workers and contractors, was quite familiar with bedbugs and their piercing, sucking mouth parts.

The topic of the forum sponsored by the Lewiston-Auburn Health Committee was what to do about the pests.

Dill, pest management specialist at the University of Maine Cooperative Extension, said there may be nothing we can do about them in the long term.

“Eradication is really tough,” Dill said. “We may be able to eradicate a bedbug population in an apartment or even a building. But eradicating bedbugs in our lifetime, that’s probably something we won’t ever see.”

The bugs have evolved alongside their human hosts, and that makes them tough to combat. They are small — adults may be 5 millimeters long, while eggs and newly hatched nymphs can be less than a millimeter in length.

That means they can hide just about anywhere.

“The thing about them is, they could be on a light switch,” he said. “The screw on a light switch, there could be a dozen eggs in the slot on that screw — or more. Bedbugs are not just in your bed, they’re not just beside your bed. They can be anywhere.”

The bugs are nervous, hiding when they sense movement, venturing out from cracks in the walls and floors to feed once every few days.

Dill blamed a number of factors for the bug’s resurgence in recent years — a more mobile society, less reliance on sprayed pesticides and evolved resistance to pesticides we do use were the top reasons.

For example, one common treatment has been to use “diatomaceous earth,” a powder that contains sharp, microscopic shards. The powder can be puffed into cracks where the bugs hide, cutting their tough cuticle shells and killing them.

In response, Dill said bedbugs have started evolving harder shells.

Many hire experts to battle the pests, according to panelists at the forum.

One tool is to use heat: Consistent temperatures above 120 degrees kills the adults and eggs instantly. But it’s expensive, said Ted St. Amand, president of Atlantic Pest Solutions, costing thousands of dollars to treat a single apartment.

“There is a heck of a learning curve when it comes to heat,” St. Amand said. “You are not just looking at the composition and the structure of the room, but the dynamics of the wall and floor coverings — plaster, carpeting. They might hold the heat, or they might deflect it.”

Chemicals and pesticides can still work well and are less expensive, but multiple treatments are necessary, Paul Morin of Modern Pest Control said.

“With chemical treatment, you don’t kill the eggs,” he said. “You have to do the treatment, wait two weeks for the eggs to hatch and then treat again to kill the hatchlings.”

Both tools are important, said Kathy Murray, an entomologist with the Maine Department of Agriculture.

“But the most important tool is knowing what you have and where,” she said. Regular inspections and awareness of the problem are the best strategies.

“We’ve had situations where someone had something precious they didn’t want to get sprayed or heated up,” Murray said. “They took it out before the treatment, then brought it back after everything was done and they reinfected the house.”

staylor@sunjournal.com