Ancient warfare captured in amber

The soldier vs. the cockroach

About 100 million years ago, a soldier beetle of an ancient type found itself under investigation by the antennae of a much larger animal, possibly a giant cockroach. Understandably alarmed, the small soldier beetle, only about a quarter of an inch long, immediately fired off a shot of offensive chemical from one of its rear glands. Just as it released its toxic dose, a wave of sap engulfed it, forever freezing the moment in amber and taking with it the antennae of the larger predator.

We would never know a thing about this tiny event from millions of years ago were it not for the preservative properties of amber. It starts out as sap dripping down a tree but has captured for us some of the most amazing, ancient finds in the history of fossils. Recent reports have included the discovery of the oldest bee species and even the presence of the malaria pathogen in the blood of an amber-preserved mosquito. Finds like this make amber a window into an ancient world showing us things we otherwise would never see.

Small-scale wars in a big world

The scene between the cockroach and the soldier bug would have been lost to history without the amber. But now we know that chemical warfare, today widely practiced by a variety of insect species, existed at the time of the dinosaurs. As Tyrannosaurus rex made its way across the landscape leaving its tri-toed footprints in the mud, soldier beetles were busy waging their war against killers on a much smaller scale.

Insects today employ this tactic so frequently that it featured as the central trait of the most frightful insect villain in movie history, the sulfuric-acid squirting super-killer in the Alien series. Some modern insects do actually shoot acid as a form of defense; in fact, the modern version of the soldier beetle fires off a mean shot of carboxylic acid at anything trying to eat it. Other nasty mixtures insects use today include chemicals that make the predator vomit or at least spit out the intended snack.

The amber that captured the David vs. Goliath battle between the hapless soldier beetle and its cockroach attacker was found in an amber mine in Myanmar, formerly Burma. This mine has been a treasure trove of biological finds trapped in amber, discoveries that tell us things about ancient ecosystems that we otherwise never would know.

What we do know is that this ancient species of soldier beetle liked to eat aphids, other little insects, and plant pollen, which may have been why it was on the tree in the first place. It had seven pairs of chemical-firing glands along its abdomen and was able to pick and choose which ones to use, depending on the angle of the predator. In the case of the amber-encased soldier beetle, it was employing only one gland and had actually achieved a successful shot, engulfing the predator’s antennae in the presumably noxious chemical before succumbing to the flowing sap.

Don’t crack my amber!

No one knows exactly what the chemical was because the person who owns the amber and the scientist who discovered the beetle refuse to allow eager entomologists to examine the encased remains. Many entomologists would be thrilled to extract DNA from this specimen, to be able to compare it to other sequenced ancient and modern samples. Others would like to identify what this earliest known practitioner of chemical warfare was using in those seven accurately firing glands. But to get at these samples, the entire specimen would have to be ground up and completely destroyed, something the amber’s owner, a collector of such pieces, refuses to allow.

And, for the geeks…a new dating for the soldier beetle?

As consolation, entomologists will have to accept another prize. This particular fossil pushes the dating of this species of soldier beetle back by 60 million years, newly placing the little bug squarely in the time of the dinosaurs.

A gal for George, the world's loneliest tortoise?

Long-lived, lonely: The tragic fate of Lonesome George

George has seen a lot in his life. He was born sometime between 80 and 200 years ago, so what exactly he’s seen remains speculative. What we do know is that in 1971, some goat herders spotted George on the island of Pinta in the Galapagos, and George’s life changed significantly. Researchers rushed to the site to find the tortoise. The reason for the rush? They thought George was the very last of his subspecies, the lone denizen of Pinta, a survivor of the combined adverse effects of whalers and goats in the Galapagos.

George’s people+goats problem

Probably within George’s memory—if he could form such memories—whalers arrived at the Galapagos islands and decimated tortoise populations by eating the animals, whose abundant meat proved irresistible to the protein-starved mariners. With the people came the goats, and the goats proceeded to eat their way through everything on Pinta that the tortoises like to eat, too, destroying all of the tortoise’s nesting sites in the process. By the 1970s, biologists were pretty sure that there were no longer any Geochelone nigra abingdonii, George’s subspecies, living on the island. Then George popped up his wrinkled head just as the goatherders were walking by.

George elicits some bizarre human behavior, ignores tortoise females

The people took George to a tortoise sanctuary, where they attempted to introduce him to the joys of female companionship. Because George was alone, species-wise, they selected a couple of females from a closely related subspecies, Geochelone nigra becki, who hailed from Wolf Island, part of the Galapagos island chain. There, George lived with the females for 30 years with nary a leering glance at them, much less successful mating. One frustrated researcher went so far as to join George in his pen, where she covered herself in eau d’ female tortoise, excretions from the female that presumably carried male-attracting pheromones. During her time with George, the male tortoise appeared to have a sort of sexual awakening, showing a bit of interest and exhibiting signs of sexual activity. The researcher even confirmed that George was indeed male and that everything appeared to be functioning normally.

Then, her research period at the sanctuary ended, and George lost his trainer in the romantic arts. Bachelor and celibate, his claim to fame remained that he was the world’s loneliest animal. He even made it into the Guinness Book of World Records as the rarest creature on Earth. His sobriquet became Lonesome George, and thousands of people came to view him at his island sanctuary. Over time, he has had his trials: a caretaker who let him eat too much, periodic overindulgence in cactus—a tortoise delicacy—that led to constipation, and a fall that almost killed him. But still, no mating.

Will George find his Ms. Right?

Then, a group of researchers tackled the job of drawing blood from tortoises on the nearby island of Isabela, where a different subspecies of tortoise lives. They performed microsatellite DNA analysis on the blood, a type of analysis that produces a DNA fingerprint that can be used to characterize a species. To their surprise, they found a tortoise among their samples who appeared to be half-George. The male tortoise had a microsatellite DNA pattern that was a 50% match for George, meaning that somewhere on the island of Isabela, a possibly-female G. n. abindonii lurked and, apparently, mated.

Now the search is on for the individual who may blow George’s place in the record books but also be the last hope for their mutual species to persist on the planet. If the tortoise is female, researchers hope to introduce her to George, possibly awakening his long-dormant libido. Meanwhile, George’s former island home of Pinta could be a tortoise Eden for the pair: the goats are gone and much of the vegetation has returned to its original ecological state. If they can find George a mate, he may very well cease to be Lonesome George and become his species’ Adam, partner to the as-yet-unidentified Eve.

%d bloggers like this: