According to a paper published in the latest issue of the Proceedings of the National Academy of Sciences, scientists at the California Institute of Technology (Caltech) found that hungry drosophila flies are extreme ultramarathon flyers, and their foraging journey can reach as far as 15 kilometers, equivalent to a person walking more than 10,000 kilometers at a time.
Scientists at the California Institute of Technology reportedly conducted experiments on a dry lakebed in California's Mojave Desert where they released thousands of fruit flies and lured them into traps containing fermented juice to determine their speed of flight.
Humans know very little about the flying abilities of drosophila black-bellied flies, and it is only now discovered that they are ultra-ultramarathon flyers.
Michael Dickinson, a biologist at the California Institute of Technology, said the flies are standard laboratory model organisms, but they have almost never been studied outside the lab, so we know very little about their ability to fly.
Led by former postdoctoral scholar Kate Letch, the team made several trips to a dry lake bed in the Mojave Desert to release fruit flies in containers.
Where to release fruit flies.
The team laid out 10 "odor traps" around the circumference 1 kilometer around the release point, each containing fermented apple juice and champagne yeast, a cocktail combination that produces carbon dioxide and ethanol that is irresistible for fruit flies.
Each "smell trap" has a camera and is equipped with a check valve, so that fruit flies can climb into the trap and fly towards the cocktail, but will not climb out again.
10 "odor traps" are set around the release point.
The container containing the fruit flies has a large amount of sugar, and the fruit flies can consume enough energy before flying. Since there is no protein in the container, hungry flies have a strong incentive to look for protein-rich foods. Previous studies in the lab have shown that a well-stocked fruit fly can fly continuously for 3 hours.
In addition, the researchers set up a weather station to measure wind speed and direction at the release site throughout the experiment, which will show how fruit flies are affected by the wind.
At predetermined times and under different wind conditions, the researchers opened the containers in batches at the release point to release fruit flies.
Researchers release fruit flies.
The first fruit flies took about 16 minutes to fly 1 km to reach the trap, corresponding to a speed of about one meter per second.
The team interpreted this speed as the lower limit, because perhaps this batch of flies circled around the dots after release, or did not fly in a completely straight line.
The "smell trap" is irresistible for hungry fruit flies.
From this, the team concluded that fruit flies can fly about 12 to 15 kilometers (7.4 to 9.3 miles) in a single flight, and fly farther if the tail wind helps.
In 2018, Dickinson's lab found that fruit flies use the sun to fly in a straight line in search of food. Flying aimlessly in circles can be deadly, so being able to navigate effectively is an evolutionary benefit.
The team believes that each fruit fly randomly chooses a direction, uses the sun to fly straight in that direction, and carefully adjusts its forward speed while allowing itself to be blown sideways by the wind. This allows it to cover as much distance as possible and increases the probability that it will encounter a wisp of odor from food.
Text/Nandu reporter Chen Lin