University of Georgia scientists have discovered a protein in fire ants that may lead to a new way of using their own biology against them. The protein is linked to red imported fire ants' senses of smell and taste. The research appears today in the journal Science.
"We discovered two variants of a protein found in fire ants and noticed that one was found only in multiple-queen colonies," said Ken Ross, an entomologist with the UGA College of Agricultural and Environmental Sciences.
"That's what peaked our interest two and a half years ago," Ross said. "It made us wonder whether this protein could affect the social behavior and structure of the colony."
To unravel the mysteries of this unfamiliar protein, UGA sought funding from the National Science Foundation and hired Michael Krieger, an evolution biologist from the University of Lausanne in Switzerland.
Krieger, an expert in the molecular biology of ants, began working to sequence the protein gene. "I isolated the protein and used this information to determine the DNA sequence of the gene," Krieger said. "Once I got the gene, then we could really get to work."
Krieger and Ross cross-referenced the protein's DNA with other DNA sequences in a national data bank. "We were able to find similar proteins, and that's how we deduced that this particular protein is a type of odorant-binding protein," Ross said.
The DNA sequence revealed the protein is related to the ants' senses of taste and smell. "We found that this protein allows the ant to capture odors from its environment and transport them to the neuroreceptor," Krieger said. "Basically, it helps the ant sense its environment."
Ants use their senses of smell and taste to regulate the number of queens in colonies and regulate the social structure. "We don't know how the protein affects the abilities of different ants to smell and taste," Ross said. "But we know the ants smell and taste queens, recognize them individually and either accept or don't accept them as egg-laying queens. And now we've discovered a protein that is likely involved in this process."
As with most scientific research, the outcome could have been much different. "It could have turned out to be a protein that regulates the numbers of segments in the ants' antenna and that wouldn't have been useful," Ross said. "As it turned out, it made perfect sense. This doesn't rule out that there are other genes involved in the ants' sensory process. There are likely to be. But this one is very important in terms of regulating the social behavior."
Ross admits this was a risky project. "The probability of finding the gene that codes for this protein was actually very low, so we're very pleased that it turned out," he said. "There are a lot of things that could have gone wrong. But, after all, we got the funding from NSF because this project was a risky one."
To continue research into the protein's potential, Ross and Krieger need more time and more funding. "It could be applied as a pest control method if we can bind an artificial compound that competes with the natural pheromone, interrupting the ants' senses," said Krieger. "This way we could make the ants see and smell queens that aren't there by sending them false signals. This would disturb the whole social organization."
If the ants smelled the presence of too many queens, Krieger said, they would get agitated and begin killing other ants in the colony.
The researchers also found the newly identified gene in other fire ants found in South American and the United States.
"It's a rather general phenomenon we've found in fire ants, but it has unbelievable potential," said Ross.
Journal
Science