Camouflage by Debris

Specimens preserved in amber. © Wang et al. in Science Advances, 2016.

We’ve featured posts here concerning camouflage plenty of times, whether in birds and their eggs, in beach-dwelling crabs, plant-mimicking insects, or strange caterpillars. That last example is the closest to the subject matter of Ed Yong’s latest post on Nat Geo’s Phenomenon blog, where he writes about insects that cover themselves in debris to hide from predators or prey alike:

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.

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.”

Read the rest of Yong’s article here.

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