You wouldn't want to be squeamish to be an entomologist, a scientist who studies bugs. Not alone do you have to watch, breed and handle them, you have to dissect them, analyse them and study their entrails to learn what they had for breakfast.

It is all in a good cause, however, advancing scientific knowledge and, hopefully, coming up with new control methods that will keep harmful insect populations down. An intensive study of damaging carpenter ants at Virginia Tech in Blacksburg, Virginia, has led to the discovery of one such product, an ant bait that is safer to use and much less likely to cause collateral damage to other insects.

Prof Rick Fell, professor of entomology in the Department of Entomology at Virginia Tech wanted to learn more about the behaviour of carpenter ants, how they foraged for food, what they liked and disliked and what they did when they brought food back to the nest. Basically he wanted to know what it was like to be a carpenter ant, aka Camponotus pennsylvanicus to come up with new control methods.

He chose an unlikely colleague in this effort, a PhD candidate who started as an art student scared of bugs. Dr Colleen Cannon from Minnesota decided the only way to overcome her phobia was total immersion in the subject.

She started by going to the library and studying books on bugs, deciding that despite being buggy they were interesting. She then did a summer entomology course which had her in the field collecting insects. She completed undergraduate studies in biology then joined Prof Fell's group, initially studying how carpenter ants survived the cold Virginia winters.

Prof Fell had colonies of carpenter ants and he needed to keep them healthy. "I was trying to develop an artificial diet for use in the lab," he explained. "We were interested in their feeding biology. We started by looking at how the ants forage.'

Carpenters are a "major nuisance pest" he said, not because they eat timber but because they like to nest in it, boring tunnels and excavating space for the queen and her eggs. They can also forage over long distances, he said, so while they could be spotted invading your house looking for groceries, they might actually be living in a tree some distance away.

When Prof Fell referred to studying ant behaviour, he did not just mean watching them amble about. You watch their movements, sure, but there are other less tasteful chores to be done. The team had to dissect the ant's fore stomach, the crop, to carry out chemical analysis of the contents. They needed to know about any seasonality in eating habits to develop a bait that would work all year round.

They discovered that carpenter ants have a fancy for high protein foods when they can get them. They also assembled an inventory of the plants, proteins and sugars that went into a typical day's munching. "Once we had an idea of that we set up a series of experiments. We looked at all of the sugars and examined whether they had any preferences."

They next looked at "particle size". The idea behind a toxic bait is to avoid spraying or causing a wide distribution of the pesticide. Rather, you encourage the insect to take it voluntarily, and in so doing delivering only a minute amount of poison. If the particle size is wrong, however, the poison will not have any effect because it will not get deep enough into the insect.

Carpenter ants have a number of mechanisms that restrict the size of what they can take in. Hairs protect the mouth parts, filtering out anything too big. A pouch in the mouth also catches big pieces and the ant can spit them out. There is a narrowing between the fore and mid-stomachs, the proventriculus, which also blocks material.

Microscopes, spectropho tometers and photoluminescent particles of various sizes were used to study movement through the ant's digestive tract. "That told us what particle size was necessary to get it deep into the gut and digested," Prof Fell said.

Ant food sharing behaviour is also important in the development of a successful bait. "With most ants, most social insects, when a forager returns with food it passes it to other ants in the nest," he said.

They used radioactive tracers to assess how quickly a food resource would be spread through the nest. This in turn dictated what type of poison to use in the bait. If it was too powerful or if the dose was too high the ant would not make it away from the dinner table, yet it had to be strong enough to kill.

Having worked out "what they like best", combined with the right toxin and particle size, the team put together a carpenter ant bait that works well but which can also "reduce the exposure to and use of pesticides", Prof Fell said. The toxin, developed by the Clorox Company, is administered in parts per million. Prof Fell and Dr Cannon, who completed her doctorate with the project, now have a patent on their technology.