What's the best way to wake up cicadas that have been sleeping for 17 years? With "jumping" dew drops of course!
Cicadas are set to emerge soon across the East Coast after a 17-year hibernation. Researchers from Duke University and James Cook University in Australia report that "jumping" dew drops help cicadas clean their wings.
These jumping droplets will assist the cicadas in cleaning their wings and other water-repellant surfaces. On these surfaces, dew drops "jump" by themselves, removing contaminants in the process, the researchers explained.
How exactly do these dew drops jump up and down by themselves? Researchers explained that forming dew drops coalesce together, the merged drop jumps off water-repellant surfaces. The jumping motion is automatic, powered entirely by the surface energy initially stored in the dew drops.
"Conventional thinking was that natural materials are self-cleaned by what is known as the 'Lotus effect', named for the way water beads on the surface of a lotus leaf and eventually rolls off taking any dirt and other contaminants with it," explains study co-author Dr Gregory Watson from James Cook University's Scanning Probe Microscopy Facility.
"But many insects have short lifespans that may not coincide with periods of rainfall. Their wings still become covered with dirt, pollen, dust and bacteria that, if not removed, may interfere with their ability to fly."
According to National Geographic, cicadas are known for their buzzing and clicking noises. Males generate this noise with vibrating membranes on their abdomens. Though the species-specific sounds may seem similar to humans, the cicadas use varying noises to attract mates or warn other cicadas.
"Most cicadas are unable to clean their own wings because of their short appendages," said Gregory Watson of James Cook University. "Furthermore, these insects commonly live in areas where there is little rain over an extended period of time. However, the areas are humid, which provides the tiny dew droplets needed to 'jump clean' their wings."
The research is published today in Proceedings of the National Academy of Sciences. Click here to watch droplets coalescing around particles before jumping off.
