Assistant Professor Floris van Breugel and postdoctoral researcher David Stupski discovered that the flies’ automatic behaviour involves lowering altitude and repeatedly making sharp turns in a fixed direction. This shows that flying flies can assess wind conditions and evolve strategies to find smells (leading to food sources) using a strategy that works well in those conditions. The flies don’t just have a preprogrammed response to smells, they respond contextually. This knowledge could potentially be applied to train more advanced algorithms for smell-sensing drones to spot chemical leaks. Credit: Chris Moran
What makes a fly fly in circles when the air is still? And why does that matter? In a paper published in Current Biology, Floris Van Breugel, an assistant professor, and S. David Stupski, a postdoctoral researcher at the University of Nevada, Reno, answer this previously unanswered question. Their answer could hold key implications for public safety, specifically how we better train robotic systems to track chemical leaks.
“Currently, there are no robotic systems that track odors or chemical plumes,” Van Breugel says, “and we don’t know how to efficiently find the source of wind-borne chemicals. But insects are incredibly good at tracking chemical plumes. If we could really understand how insects do this, maybe we could train cheap drones to use a similar process to find chemical sources or chemical leaks.”
A fundamental challenge in understanding how insects track chemical plumes (essentially, how a fly finds a banana in the kitchen) is that wind and smell cannot be manipulated independently.
To address this challenge, van Bruegel and Stupski employed a new technique called optogenetics, which allows them to remotely control neurons in the antennae of flying fruit flies, specifically the “olfactory” neurons, by genetically introducing light-sensitive proteins. This allowed them to give the flies the same virtual olfactory experience in different wind conditions.
What Van Breugel and Stupski wanted to know was: how do flies find odors when there is no wind? After all, this is probably the wind experience of a fly searching for bananas in a kitchen. The answer is found in the article “Wind Controls Olfactory-Driven Search States During Free Flight”.
According to Van Bruegel, flies use environmental cues to sense air currents and wind direction and respond to them to find food sources. When wind is present, these cues automatically trigger a “cast-and-surge” behavior: when flies encounter chemical plumes (indicating the presence of food), they charge into the wind, and when they lose their sense of smell, they cast (move from side to side). While cast-and-surge behavior has long been understood by scientists, Van Bruegel says that how insects find scents in still air was fundamentally unknown.
Through their research, van Bruegel and Stupski discovered another automatic behavior, the “dip and turn,” in which flies lose altitude and make repeated sharp turns in a consistent direction. Flies consistently and repeatedly perform this innate movement, even more frequently than the cast and surge behavior.
Van Bruegel says the most interesting thing about this discovery is that it shows that flying flies can clearly assess wind conditions – the presence or absence of wind and its direction – and then evolve strategies that work well in those conditions. The fact that flies can do this is really remarkable: if you stick your head out of a moving car window, can you tell if there’s a breeze?
Flies don’t just react to odors with the same programmed response every time, like simple robots, but respond in a way that’s tailored to the situation. This knowledge could potentially be applied to train more advanced algorithms for odor-detecting drones to find the source of chemical leaks.
So next time you’re trying to swat a fly in your house, consider the fact that it might actually know its natural environment a little better than you do — and maybe open a window to let the fly out.
Further information: Wind-gated olfactory-driven exploration of free flight, Current Biology (2024). DOI: 10.1016/j.cub.2024.07.009. www.cell.com/current-biology/f … 0960-9822(24)00912-6
Courtesy of University of Nevada, Reno
Citation: New understanding of fly behavior holds promise for applications in robotics and public safety (July 26, 2024) Retrieved July 27, 2024 from https://phys.org/news/2024-07-fly-behavior-potential-application-robotics.html
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