[Video] To find food, fruit flies can fly 6 million times the length of its body

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[Video] To find food, fruit flies can fly 6 million times the length of its body

Scientists at the California Institute of Technology have now discovered that fruit flies They can fly 15 kilometers (approximately 9 miles) in one trip, which is 6 million times the length of their body, or more than 10,000 kilometers as an average person. If compared according to body length, this is farther than many migratory bird species can fly in a day.

To discover this, the team conducted experiments on a dry lake bed in the Mojave Desert in California, releasing fruit flies and lure them into traps containing fermented juices to determine their maximum speed . Related papers were published in the Proceedings of the National Academy of Sciences on April 20.

The motivation for this work is a long-standing paradox, which was developed in the 1940s by Theodosius Dobzhansky and other studies of fruit in the Southwestern United States. Pioneer discovery of population genetics of fly species. Dobzhansky and others found that the genetic similarity of fruit fly populations thousands of kilometers apart could easily explain much more easily than their estimation of how far these little fruit flies can actually travel. In fact, when biologists release fruit flies outdoors, these insects often just buzz around a short distance, just like they are in our kitchen.

Do fruit flies behave differently when looking for food in the wild? In the 1970s and 1980s, a group of population geneticists tried to solve this contradiction. They coated hundreds of thousands of fruit flies with phosphor and released them into Death Valley in one night. It is worth noting that the team found some fluorescent fruit flies in a rotten banana bucket 15 kilometers away the next day.

To measure how fruit flies disperse and interact with the wind, the team designed a “release and recapture” experiment. Led by former postdoctoral scholar Kate Leitch, the team has traveled to Coyote Lake, a dry lake bed in the Mojave Desert 140 miles from the California Institute of Technology, and dragged hundreds of thousands of common The laboratory fruit fly-Drosophila melanogaster.

The purpose is to release these fruit flies, lure them into traps at a set location, and measure the time it takes for the insects to fly there. In order to do this, the research team set up 10 “odor traps” in a circle, each trap located within a kilometer of the release site. In each trap there is an attractive cocktail of fermented apple juice and champagne yeast. This combination produces carbon dioxide and ethanol, which is irresistible to fruit flies. Each trap has a camera and is equipped with a one-way valve so that fruit flies can climb into the trap and walk towards the cocktail, but will never come out again. In addition, the researchers set up a weather station to measure the wind speed and direction of the release site throughout the experiment; this will show how the flight of fruit flies is affected by the wind.

In order not to interfere with their flight performance, the research team did not coat the fruit flies with identifiers such as phosphors. So, how do they know that they have caught their own fruit flies? Before the release, the research team first placed a trap and inspected it over time. It was found that although wild Drosophila melanogaster was found in the jujube orchard in the Mojave area, they were found in Lake Coyote. Extremely rare.

The fruit flies released by the team were initially collected on a fruit stand and then raised in the laboratory, but they were not genetically modified in any way. The team conducted experiments after obtaining permission from the Bureau of Land Management.

During the experiment, the research team opened the bucket containing the fruit flies to the center of the trap circle. There is a lot of sugar in the bucket so that the insects will provide sufficient energy for their flight; however, they do not contain protein, which gives fruit flies a strong motivation to find protein-rich food. The research team estimated that fruit flies would not be able to smell the trap from the center of the ring, forcing them to spread out and search.

The team repeated these experiments under different wind conditions. The first batch of fruit flies took about 16 minutes to walk one kilometer to reach the trap, and the corresponding speed was about 1 meter per second. The team interpreted this speed as a lower limit (perhaps these first fruit flies circled a little bit after release, or did not fly in a perfect straight line). Previous studies in the laboratory have shown that a full-fed fruit fly has the energy to fly continuously for three hours; by inference, the research team concluded that a black fly can fly approximately 12 to 15 kilometers in a single flight, even in gentle conditions. In the breeze, if you have the help of the tail wind, you can fly farther. This distance is approximately 6 million times the average body length of fruit flies (2.5 millimeters, or one-tenth of an inch). As an analogy, it’s like the average person only walks more than 10,000 kilometers in a trip-about the distance from the North Pole to the equator.