Our military has donned camouflaged suits for a long time--perhaps since their existence. While we would like to think that these disguises we have created were an invention intrinsic to humans, that’s not the case. In fact, we’ve been beaten to it by over a hundred million years.
Bo Wang, from the Nanjing Institute of Geology and Paleontology of the Chinese Academy of Sciences, and his colleagues recently discovered insects that could be described as masters of disguise. These insects were found encased in amber that dates back to the Cretaceous Period.
What they learned was that these insects wrapped themselves with pieces of plant matter, dirt, and even sections of other bugs’ exoskeleton in order to hunt prey or hide from predators. As history has shown though, their unique camouflage didn’t help them escape from death. The insects most likely stumbled upon some sticky tree resin and with the passage of time, they fossilized into the amber. Luckily for us, amber fossils preserve the little bits of plant matter, insects' exoskeletons, dirt, and other tiny particles that other preservation processes do not. This allowed Wang and his group of researchers to get a comprehensive idea of what these insects would look like in action.
"Reconstructing the behavior of ancient animals is a challenge to paleontologists because ephemeral events are hardly preserved in the rock," says Dr. Wang "But occasionally few fossils document particular behaviors directly. We have some direct evidence of debris-carrying behavior; some fossils are carrying some debris on their back, which are trapped in amber."
Wang and his group looked through more than 300,000 amber specimens from Myanmar, China, France, and Lebanon looking for bugs that showed trash-carrying behavior. They reported 39 specimens in a paper published in the journal Science Advances. The paper suggests that the behavior is present in three unique genera of insects: Chrysopidae (green lacewings), Myrmeleontoid (split-footed lacewings and owlflies), and Reduviidae (assassin bugs). Moreover, the report claims that the debris-carrying behavior was established well over 130 million years ago.
"These ancient fossils are quite remarkable," says George Poinar, an entomologist at Oregon State University known for his research on amber fossils. “[They] show that insect behavior was very similar in the Cretaceous to what it is today.”
The bugs carry quite the load on their backsides. To help them with the effort, there are some interesting structures on their back. The most common one consists of long filaments or shorter bristles acting as anchors for the trash cloak.
Covering yourself with stuff you find on the ground and dead bugs is a more complex action than it may at first seem. First, it requires the camouflagers to effectively perceive which materials will empower them to successfully shroud themselves. At that point, they have to gather those materials and use them to make a camouflage that flawlessly fits their surroundings. "Debris-carrying, a behavior of actively harvesting and carrying exogenous materials, is among the most fascinating and complex behaviors because it requires not only an ability to recognize, collect, and carry materials but also evolutionary adaptations in related morphological characteristics,"write the authors in their new paper.
What’s more to say, all the insects that were in the study are juveniles. This means that the bugs had created their debris-coats at a young age. This, Wang says, is definite evidence of a more intricate evolutionary process.