Move over, Simone Biles – there's an insect with even better backflips. Globular springtails might only be a couple of millimeters long, but can jump and spin 60 times their own body height into the air, and new research looks even deeper at this incredible acrobatic feat.
Springtails (Dicyrtomina minuta) are pretty common little critters with over 8,000 species (the ones from this study were found in co-author Adrian Smith's back garden). They have no defenses from predators besides leaping, so jumping out of the way is the only option.
“When globular springtails jump, they don’t just leap up and down, they flip through the air – it’s the closest you can get to a Sonic the Hedgehog jump in real life,” said Smith, research assistant professor of biology at North Carolina State University and head of the evolutionary biology and behavior research lab at the North Carolina Museum of Natural Sciences, in a statement. “So naturally I wanted to see how they do it.”
This proved something of a challenge: the springtails are both tiny and very very fast. So fast, in fact, that watching with the naked eye or even a slow-motion camera just wasn’t going to cut it.
“Globular springtails jump so fast that you can’t see it in real time,” Smith says. “If you try to film the jump with a regular camera, the springtail will appear in one frame, then vanish. When you look at the picture closely, you can see faint vapor trail curlicues left behind where it flipped through the one frame.”
Instead, the team used cameras that shot at 40,000 frames per second – the camera on a normal phone shoots at 30. To encourage the springtails to jump in front of the cameras, the researchers either shone a light or gently tapped them with a paintbrush.
The slow-mo revealed that the springtails don’t use their legs to jump – instead, they have a funky appendage called a furca that is hidden underneath their abdomen most of the time. When it's time to flip into the air away from predators or researchers, the furca unfolds forked ends that are pushed against the ground, launching them away into their spinning backflips. They also discovered that the springtails pretty much always travel backwards or to the side, never forwards.
“It only takes a globular springtail one thousandth of a second to backflip off the ground and they can reach a peak rate of 368 rotations per second,” Smith said. “They accelerate their bodies into a jump at about the same rate as a flea, but on top of that they spin. No other animal on earth does a backflip faster than a globular springtail.”
The landing, however, was something of a game of chance. The team discovered two styles of landing: the not-so-glamorous bouncing to a stop, or the use of a forked sticky tube called a collophore that the springtails can use to stop themselves and slow down immediately. They called these types of landing "anchored", but the less controlled landings were just as common.
“This is the first time anyone has done a complete description of the globular springtail’s jumping performance measures, and what they do is almost impossibly spectacular,” Smith said. “This is a great example of how we can find incredible, and largely undescribed, organisms living all around us.”
The paper is published in the journal Integrative Organismal Biology.