Chemistry behind bombardier beetle's extraordinary firepower

Date: June 16, 2020

Source: Stevens Institute of Technology

If you want to see one of the wonders of the natural world, just startle a bombardier beetle. But be careful: when the beetles are scared, they flood an internal chamber with a complex cocktail of aromatic chemicals, triggering a cascade of chemical reactions that detonates the fluid and sends it shooting out of the insect's spray nozzle in a machine-gun-like pulse of toxic, scalding-hot vapor. The explosive, high-pressure burst of noxious chemicals doesn't harm the beetle, but it stains and irritates human skin -- and can kill smaller enemies outright.

The beetle's extraordinary arsenal has been held up by some as a proof of God's existence: how on earth, creationists argue, could such a complex, multistep defense mechanism evolve by chance? Now researchers at Stevens Institute of Technology in Hoboken, N.J. show how the bombardier beetle concocts its deadly explosives and in the process, learn how evolution gave rise to the beetle's remarkable firepower.

"We explain for the first time how these incredible beetles biosynthesize chemicals to create fuel for their explosions," said Athula Attygalle, a research professor of chemistry and lead author of the work, which appears today in the July 2020 issue of the Science of Nature. "It's a fascinating story that nobody has been able to tell before."

To trace the workings of the beetle's internal chemistry set, Attygalle and colleagues at University of California, Berkeley used deuterium, a rare hydrogen isotope, to tag specially synthesized chemical blends. The team led by Kipling Will then either injected the deuterium-labeled chemicals into the beetles' internal fluids, or mixed them with dog food and fed them to the beetles over a period of several days.

Attygalle's team sedated the bugs by popping them in the freezer, then gently tugged at their legs, annoying the sleepy insects until they launched their defensive sprays onto carefully placed filter papers. The team also dissected some beetles, using human hairs to tie closed the tiny ducts linking their chemical reservoirs and reaction chambers, and sampling the raw chemicals used to generate explosions.

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Toads Eat Beetles. Sometimes, Beetles Make Them Regret Their Meal Choice – via Herp Digest

Trilobites, New York Times, 

By Douglas Quenqua, FEB. 6, 2018,

Go to http://nyti.ms/2Ci8IRl for short video

Photo by Dr. Shinji Sugiura, et al., Kobe University.

                       

For most prey, the game is over once they’ve been swallowed. But one species of beetle can escape from a toad’s stomach nearly two hours after being eaten, according to a new study.

Found in wooded areas on nearly every continent, bombardier beetles — a group that consists of more than 500 species — get their name from their signature defense mechanism: When threatened, they shoot a hot chemical spray from their rear end. In Japan, the insects have long been known as, “the farting bug.”

Toads have been observed vomiting bombardier beetles after eating them, but no one knew exactly why, or how long the beetles survived after their brush with digestion.

To better understand the beetle’s defenses, two biologists from Kobe University fed a species of bombardier beetle to two different species of toad collected from forests in central Japan. One toad species shared its natural habitat with that particular species of beetle, while the other was unlikely to encounter it in the wild.

After the beetles were swallowed, a small explosion could be heard inside each toad, indicating that the insects were firing their defenses. Overall, 43 percent of the toads vomited the beetles, taking anywhere from 12 to 107 minutes.

Most important (at least to the insects): Despite being covered in mucus, meaning they had entered the toads’ digestive system, every evicted beetle was still alive, and all but one survived for another two weeks. No toads died on account of eating the beetles.

“It surprised us that the beetles vomited by toads were still alive and active,” said Shinji Sugiura, an author of the study, which was published Tuesday in the journal Biology Letters.

But some toads were better able to digest the beetles than others. Only 35 percent of the toads that shared habitat with the beetles coughed them up, compared to 57 percent of the toads with no common habitat. The findings suggest that regular exposure to bombardier beetles has allowed some toads to evolve a tolerance to their poison.

Size mattered, too. Large beetles escaped more frequently than small beetles, and small toads were more likely to vomit beetles than large toads. The reason, presumably, is that large beetles are able to produce more poison, and smaller toads are less able to tolerate it, said Dr. Sugiura.

To be sure that the beetles were using their spray to escape, the researchers also fed the toads beetles that had been forced to expel their poison just before being consumed. Nearly all of those beetles were successfully digested.

The authors say it’s still not clear whether the beetles have evolved a resistance to a toad’s digestive fluids and enzymes, which may have helped them survive their ordeal inside a toad’s belly. That may be the case, but it’s also possible that their poison spray prevented the toads from producing enough digestive juices to harm them.

Bombardier beetles are not the only creatures that can shoot toxic liquids. Fire ants, spitting cobras and even some species of birds are known to disable their prey with harmful sprays.

Based on the current study, Dr. Sugiura predicted that other spraying species may also be able to escape from a predator’s stomach. “Well-defended species that force some predators to vomit will be found in other animal groups,” he said. Consider yourselves warned, predators.

Chewbacca bat, beetle with explosive farts among oddities spotted on Mozambique expedition

The "Chewbacca" bat, a cave-dwelling frog, bombardier beetles that unleash explosive farts as a defense mechanism, and a diminutive elephant shrew were among hundreds of species documented during a one-month survey of a park that was ravaged during Mozambique's 17-year civil war. The findings suggest that biodiversity in Gorongosa National Park in Central Mozambique is well on the road towards recovery, opening a new chapter for the 4,000-square-kilometer protected area.

Between April 15th and May 15th 2013, a team of 15 scientists conducted an inventory of plants and animals on the Cheringoma Plateau in the eastern part of Gorongosa. The researchers used a variety of methods, including pitfall traps, mist nets, pheromone traps, remote cameras, and ultrasonic sound detectors, to document the area's plants, mammals, birds, reptiles, amphibians, beetles, ants, grasshoppers, katydids, and praying mantids. Overall the expedition turned up 1,200 species of animals and plants on the Cheringoma Plateau, including dozens of species never before documented by science.

Read more athttp://news.mongabay.com/2013/0604-gorongosa-cheringoma-discoveries.html#eEShzcEvXsZ7EQrD.99