Dinosaur-era bugs knew how to camouflage

Washington DC: It turns out, insects have been perfecting the art of disguise for a hundred million years.

An international research team, with participation from the University of Bonn, has now discovered the oldest known evidence of bugs using the 'invisibility cloak.' The custom-tailored "costumes" also permit conclusions about the habitat at the time.

The larva of the lacewing attacks a pseudoscorpion and uses its powerful mouthparts to suck it dry. The larva then puts the remains of the dead prey on its back. The outlines of the lacewing are now unrecognizable. It looks more like a dead pseudoscorpion. This camouflage protects the lacewing against being recognized by predators and at the same makes it easier to hunt its own prey.

"With this 'disguise', the lacewing larva pretends to be someone completely different," said Dr Jes Rust, adding "Using the pieces of its prey, it even takes on the smell of the pseudoscorpion".

The scene plays out in the Cretaceous and is recorded as a "snapshot" in amber. The team examined a total of 35 insects preserved in amber. With the aid of grains of sand, plant residue, wood fibers, dust, or even the lifeless shells of their victims, the larvae achieved camouflage to perfection. The amber samples come from Myanmar, France, and Lebanon.

Some larvae fashioned a kind of "knight's armor" from grains of sand, perhaps to protect against spider bites. In order to custom-tailor their "camo", they have even adapted their limbs for the purpose. The larvae were able to turn their legs about 180 degrees, in order to transport the grains of sand onto their back. Others cloaked themselves in plant residue, in order to become one with their surroundings, making them almost undetectable to predators.

"It is very surprising how early in evolution such complex insect behavior developed: The larvae had to search actively for suitable 'camouflage material', pick it up, and cloak themselves with it", said team leader Bo Wang.

Based on the camouflage of the various amber insects, the research team reached conclusions about their habitat at the time. Examination of an ancestor of the ant lion under the microscope showed that the camouflage consisted of tiny pieces of fern. "These are fern species, which, for example, were the first types of plants to recolonize after fires", explained Dr Torsten Wappler.

Presumably, in the Cretaceous, a bush fire raged that damaged the trees and stimulated unusually strong resin production. In this way, the "costumed" larvae were trapped in the tree resin and the scene preserved to this today.

The results are published in the journal "Science Advances."