When planning your next picnic, make sure you leave the tuna at home. University of Georgia entomologists have found several ant species prefer tuna over other foods they tested.
"We did this study to find out what food products native ants like best," said Mark Brinkman, a research scientist with the UGA College of Agricultural and Environmental Sciences.
Unlike picnickers, entomologists want to attract ants. "We want to find out how many species of ants are present in Georgia," Brinkman said. "Using food baits to collect ants is the first step in this project."
Tuna and Honey: The Top Choices
For the study, Brinkman narrowed down the ant menu to tuna in oil, uncooked eggs, honey and peanut oil. "Peanut oil is a fat, honey is a sugar, egg is a protein and tuna is a protein in oil," he said. "I chose these foods to represent several food groups."
Brinkman said he decided to test eggs as a food bait because of his observations in nature. "I have often seen them eating bird eggs that have fallen out of nests," he said.
After testing the food baits last summer, Brinkman found tuna in oil to be the top choice of ants in Georgia. Of the more than 5,000 ants collected during the study, 4,594 were caught using the tuna bait. Honey was the second favorite food bait attracting some 355 ants and egg was the third choice attracting some 294 ants. Only 50 ants were caught in the peanut oil baits.
"The majority of the ants collected with tuna baits were fire ants," Brinkman said. "It's not that other species don't like tuna, too. Once fire ants show up, they monopolize a food bait."
There's More Than One Way to Catch Ants
Brinkman's study helps UGA entomologists lighten their load when collecting ant species for research. "Now instead of taking all these different food baits along, we take the tuna baits," he said.
Food baits, like the tuna one used by UGA researchers, may prove to be very effective tools for attracting ants, but UGA entomologists can't rely on it alone. "We attracted 13 species of ants with the food baits and there may be a couple of hundred species in Georgia," Brinkman said.
To collect as many species as possible, UGA entomologists also use pitfall traps to collect ants. "Basically, you drill a hole in ground, insert a vial and the ants fall in," Brinkman said.
Researchers actively search for ants in nature, too, and collect them in leaf litter samples. "We collect leaf litter, put it in the top of a large funnel and heat it up," he said. "The ants fall down into a collecting station."
(Sharon Omahen is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.)