100 Million Years of Decorating Yourself In Junk

Every year, in northern Myanmar, thousands of farmers pull tonnes of Cretaceous amber out of the ground, and send the glistening nuggets to local markets. For six years, Bo Wang from the Chinese Academy of Sciences and his colleagues have visited the markets and sifted through 300,000 of the glistening nuggets. It was a lot of work. Then again, it takes a lot of work to find animals that spent their whole lives trying not to be found.

Within the amber, Wang’s team identified dozens of ancient insects that camouflaged themselves by adorning their bodies with junk. They had short bristles and elaborate feathery tubes, onto which they stuck sand, soil, wood fibres, bits of ferns, and even body parts of other insects. They were the earliest animals that we know of to camouflage themselves, some 100 million years ago.

Many living creatures still embellish their bodies in debris. The aptly named decorator crabs, for example, look like walking bundles of algae and seaweed. The larvae of caddisflies live in tubes made of rock, sand, plants, and other underwater detritus, bound by silk. And one grisly species of assassin bug wears a coat made from the corpses of its ant prey.

VIDEO: Carrier crabs are known for toting objects around—sometimes seaweed or a broken shell, and occasionally a shield made of a live sea urchin. 

The larvae of lacewings are especially prone to carrying debris. These youngsters are voracious predators of aphids and other bugs, and they in turn are hunted by wasps, spiders, and other cannibalistic lacewings. By coating themselves in trash, they gain a disguise—or, at worst, a physical shield.

This behaviour is an ancient one. In 2012, Ricardo Pérez-de la Fuente described a 110-million-year-old larval green lacewing that dressed itself in junk. Like its modern relatives, it had long legs and sickle-shaped jaws. But its trash-carrying structures were unusually elaborate: a few dozen tubes, longer than its own body, each of which branched into smaller, trumpet-shaped fibres. The creature was effectively carrying a wastepaper basket on its back. As I wrote at the time:

“De la Fuente called it Hallucinochrysa diogenesi, a name that is both evocative and cheekily descriptive. The first part comes from the Latin “hallucinatus” and references “the bizarreness of the insect.” The second comes from Diogenes, the Greek philosopher, whose name is associated with a disorder where people compulsively hoard trash.”

The creature was effectively carrying a waste-paper basket on its back.

At the time, the Hallucinochrysa was a singular oddity. “[The amber piece] is not well-preserved, and the insect is not complete,” says Wang. “Some people think that there isn’t robust evidence to support its camouflaging behaviour.” He begs to differ. His team has now identified 39 similar specimens, including 34 from Burmese amber and five others from French and Lebanese samples.

Two of them, both green lacewings, share the same extreme structures as Hallucinochrysa: elaborate baskets of tubes sprouting from their backs. One of the larvae was carrying the remains of other insects in its basket. These were likely its prey: lacewing larvae inject their victims with a liquefying saliva and then suck their juices out, leaving behind an empty husk. They then use their long jaws to place the bodies on their backs, and become wolves in sheep’s clothing. The ancient lacewings probably did the same.

The other specimens belonged to three different families of insects—two groups of lacewings, and one lineage of assassin bugs. Much like their living counterparts, they used short hairs on their flanks and backs to entangle a wide range of debris, including sand grains, bark pieces, and scorpion fragments. They carried fern hairs, too. Specifically, they carried hairs from a group of ferns that specialised in re-colonising forests that had been scorched by fires. As I wrote at the time of Hallucinochrysa’s discovery:

“Ironically, those same fires would have stimulated the trees to produce more resin, which would have trapped many an insect in liquid tombs that eventually fossilised into amber. Hallucinochrysa may have blended into the forest of its time, but its beautiful remains tell us a surprising amount about what those forests were like. And the forests, in turn, set up the perfect conditions for Hallucinochrysa’s body to endure to this day.”