Feb. 1, 2007 — Fruit flies are likely to survive, and possibly thrive, as the globe warms, researchers predict.
While many insects will perish as temperatures rise, the researchers believe fruit flies will become better at finding food. The research team, from Australia and Denmark, published its findings in the latest issue of the American Naturalistjournal.
Fruit flies appear on nearly every continent, with more than 80 species in Australia alone. They can destroy fruit and vegetable crops, so farmers spend millions of dollars each year trying to control them.
A research team including Professor Ary Hoffman, from the University of Melbourne's Center for Environmental Stress and Adaptation Research, set out to test how fruit flies react to extreme fluctuations in temperature.
The researchers exposed around 20,000 Drosophila melanogaster fruit flies to heat 'hardening' treatments, toughening them up with short bursts of high temperatures. They then released them into the wild along the River Murray near Echuca, north of Melbourne.
They used the likelihood of the flies finding their way to a supplied food source (a bait) as an estimate of how 'fit' the flies were.
The research team found that heat-toughened flies were much more likely to be caught at the baits in very hot temperatures; the untreated flies were much more often caught at cooler temperatures; and the flies did equally well on intermediate days.
"The flies got tougher [when exposed to heat] but at the same time there was a price to pay for being tougher," Hoffman said. "In hot conditions the flies were very good at finding food ... but they didn't do as well when it cooled down."
Scientists believe that climate change will make the weather more variable. And the research team believes that 'heat hardening' will play a major role in the future of the fruit fly, especially during peaks in summer temperatures.
"What this research tells us is that the fruit fly has remarkable capacity for dealing with extreme hot conditions," said Hoffman. "They can toughen up and survive [extreme] conditions quite well. They do pay a price, but they will persist; these guys are real survivors."
The scientists say the drosophila flies in their experiments simulate the more troublesome Q or Queensland fruit fly.
