New research from Cornell AgriTech is shedding light on how a tiny fruit fly from Southeast Asia is able to survive New York’s freezing winters.
Drosophila suzukii was first found in New York about a decade ago. The fruit fly (more accurately referred to as a vinegar fly) can devastate crops including raspberries, blackberries, blueberries, strawberries, sweet cherries, peaches, grapes, and tomatoes.
It had been assumed that D. suzukii overwintering success relies solely on physiological adaptations to cold, but the study, published Feb. 7 in the journal Pest Management Science, reveals a more complex picture. It shows that these flies actively choose suitable habitats and respond to changing conditions like temperature and ground moisture. This new understanding will be critical for developing effective pest management strategies and alerting growers about potential fly populations based on winter conditions.
“These fruit-feeding Drosophila, originally from tropical regions, have moved into temperate zones but lack the biochemical adaptations to survive prolonged freezing temperatures,” said Greg Loeb, professor of entomology at Cornell AgriTech and a co-author of the paper. “We’re trying to understand its biology better, to come up with new ways and new approaches to manage it.”
Binita Shrestha, a postdoctoral researcher at Cornell AgriTech, and Dara Stockton, a former postdoctoral researcher who is now an entomologist at U.S. Department of Agriculture Animal and Plant Health Inspection Service, are the paper’s first authors.
The study, conducted at three vineyard sites in the Finger Lakes region, found that these fruit flies seek specific habitats and adapt their behavior to fluctuating winter conditions. D. suzukii were most abundant in wooded areas and near pomace piles, preferring these locations for overwintering. However, they did not congregate in specific places, making it difficult to target them with control agents during winter.
Surprisingly, the flies were rarely found within vineyards or winery facilities, indicating they aren’t just seeking warmth for the winter. The study also examined the impact of ground cover on the survival of lab-raised D. suzukii accustomed to the cold. Insulating materials like straw helped them survive sustained freezing temperatures. In addition, during warmer periods with snowmelt and potential flooding, the flies’ ability to move vertically becomes crucial to avoid drowning.
“They find habitats that give them the best chances of surviving and are active during slight warm-ups, likely feeding during winter,” Loeb said.
The study was funded by the Specialty Crops Research Initiative from the U.S. Department of Agriculture's National Institute of Food and Agriculture.
Christina Szalinski is a freelance writer for the College of Agriculture and Life Sciences.
