Scientists discover previously unknown jumping behavior in insects

A team of researchers has discovered jumping behavior that’s entirely new to insect larvae, and there’s evidence it happens in a range of species – we just haven’t noticed it before.

The previously unrecorded behavior occurs in the larvae of a species of bordered flat bark beetle (Laemophloeus biguttatus). Specifically, the larvae are capable of leaping through the air, with each larva wrapping itself in a loop as it leaps forward. What makes these jumps unique is how the larvae are able to pull it off.

“Jumping at all is extremely rare in the larvae of beetle species, and the mechanism they use to execute their leaps is – as far as we can tell – never before recorded in insect larvae,” says Matt Bertone. , corresponding author of a paper on the discovery and director of the Plant and Insect Disease Clinic at North Carolina State University.

Although there are other species of insects capable of prodigious leaps, they rely on what is called a “latchet spring actuation mechanism”. This means that they basically have two parts of their body clinging to each other as the insect exerts force, building up a significant amount of energy. The insect then unlocks both parts, releasing all of that energy at once, allowing it to spring out of the ground.

“What makes L. biguttatus so remarkable is that he makes these jumps without locking two parts of his body together,” Bertone says. “Instead, it uses claws on its paws to grip the ground as it builds up this potential energy – and once these claws release their grip on the ground, this potential energy is converted into kinetic energy, propelling it toward the sky.”

The discovery of the behavior was somewhat fortuitous. Bertone had collected a variety of insect samples from a decaying tree near his lab to photograph when he noticed these beetle larvae appear to be jumping.

Bertone and the article’s co-author Adrian Smith then decided to videotape the behavior in order to better understand what was going on. It was then that they began to understand how peculiar the behavior was. Smith is an assistant research professor of biological sciences at NC State and director of the Evolutionary Biology and Behavior Research Laboratory at the North Carolina Museum of Natural Sciences.

“The way these larvae jumped was impressive at first, but we didn’t immediately realize how unique it was,” says Bertone. “We then shared it with a number of beetle experts across the country, and none of them had seen the jumping behavior before. That’s when we realized we needed to look at some closer how the larvae did what they did.

To determine how L. biguttatus was able to perform his stunts, the researchers filmed the jumps at speeds of up to 60,000 frames per second. This allowed them to capture all of the external movements associated with jumping and suggested that the legs were essentially creating a locking mechanism with the ground.

The researchers also performed a muscle mass assessment to determine if it was possible for the larvae to make their leaps using only their muscles, instead of using a locking mechanism to store energy. They found that the larvae did not have enough muscle to launch themselves into the air as far or as fast as they had been filmed jumping. Therefore, clinging to the ground was the only way for the larvae to achieve their aerial feats.

Meanwhile, in an unrelated video about jumping maggots, Smith had included a short snippet of jumping behavior in L. biguttatus. This video was seen by a researcher in Japan named Takahiro Yoshida, who had witnessed similar leaps in the larvae of another species of beetle called Placonotus testaceus, but had not posted anything regarding the behavior.

“We don’t have high-speed images of P.testaceus, but the video evidence we have from Yoshida’s lab suggests that this previously unknown behavior is found in two different genera that aren’t even closely related,” Bertone says.

“It raises a lot of questions. Did this behavior evolve separately? Is it found in other beetle species? Are these genres more closely related than we previously thought? There is a lot of interesting work to be done here.

Video of jumping behavior in L. biguttatus can be found at https://www.youtube.com/watch?v=y-b73G96UIQ.

The article, “A Novel Power-Amplified Jumping Behavior in Larval Beetles (Coleoptera: Laemophloeidae)”, is published open access in the journal PLOS ONE. The article was co-authored by Yoshida, Tokyo Metropolitan University; Joshua Gibson, University of Illinois at Urbana-Champaign; and Ainsley Seago, from the Carnegie Museum of Natural History. The work was carried out with partial support from the Japan Society for the Promotion of Science for Young Scientists.

-ship-

Note to editors: The summary of the study follows.

“A new power-amplified jumping behavior in beetle larvae (Coleoptera: Laemophloeidae)”

Authors: Matthew A. Bertone, North Carolina State University; Joshua C. Gibson, University of Illinois at Urbana-Champaign; Ainsley E. Seago, Carnegie Museum of Natural History; Takahiro Yoshida, Tokyo Metropolitan University; and Adrian A. Smith, North Carolina State University and North Carolina Museum of Natural Sciences

Published: Jan 19, PLOS ONE

Summary: Insect larvae use many methods of locomotion. Here we describe a previously unknown jumping behavior in a group of beetle larvae (Coleoptera: Laemophloeidae). We analyze and describe this behavior in Laemophloeus biguttatus and provide information on similar sightings for another species of laemophloeid, Placonotus testaceus. Laemophloeus biguttatus the larvae precede the jumps by arching their bodies while gripping the substrate with their legs over a period of 0.22 ± 0.17s. This is followed by a rapid ventral rolling of the body after the larvae release their grip which propels them into the air. Larvae reached take-off speeds of 0.47 ± 0.15 m s-1 and traveled 11.2 ± 2.8 mm (1.98 ± 0.8 body lengths) horizontally and 7.9 ± 4 .3 mm (1.5 ± 0.9 body lengths) vertically during their jumps. Conservative estimates of power output revealed that some, but not all, jumps can be explained by direct muscle power alone, suggesting Laemophloeus biguttatus can use a latch-mediated spring actuation mechanism (LaMSA) in which the interaction between the larval legs and the substrate serves as a latch. MicroCT scans and SEM imaging of the larvae revealed no noticeable changes that would aid jumping. Although further experiments could not be performed to test hypotheses about the function of these jumps, we postulate that this behavior is used for rapid locomotion which is more energy efficient than crawling the same distance to disperse. of their temporary habitat. We also summarize and discuss jumping behaviors in insect larvae for additional context of this behavior in laemophloeid beetles.

Comments are closed.