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Recently found ancient insect decorated itself with skeletons of its preys

Researchers from the Chinese Academy of Sciences, have discovered a 100 million-year-old insect preserved in tree resin. Providing new findings on the evolution of debris-carrying bugs and their old behavior.

Camouflage is a popular action among the military and enthusiastic hunters. Humans have been performing camouflage for thousands of years to protect themselves in dangerous environments.

Researchers from the Chinese Academy of Sciences, have discovered a 100 million-year-old insect preserved in tree resin. Photo credit: Green lacewing larvae from mid-Cretaceous Burmese amber. Wang et al. Sci. Adv. 2016; 2 : e1501918 / Seeker

A recent discovery has found ancient juvenile insects used the same technique to protect themselves from predators and confuse their prey before attacking.  Researchers are now able to determine aspects of the everyday life of an insect that lived 100 million years ago.

Ancient bugs covered themselves with debris, dirt, wood, leaves and even the exoskeletons of their preys to remain undercovered. It appears that while hiding in trees, some got attached to amber and had their bodies preserved for millions of years.

A research team from the Chinese Academy of Sciences led by Bo Wang has been studying more than 300,000 amber fossils from all over the world. The team has recently found 39 examples of ancient insect camouflage and published their findings in the journal Science Advances.

Self-decoration among ancient insects

Despite being very handy on hiding from predators, these insects were not able to avoid getting stuck on tree resin that after sometimes hardened and preserved them as fossils for Bo Wang’s team to study.

Amber preservation is one of the best methods for researchers to study since it maintains the insect as it was at the moment of its sticky death and maintains pieces of dirt and particles from the ancient environment.

Wang’s research team investigated over 300,000 specimens from locations such as Lebanon, France, Myanmar, and China to discover 39 ancient species that described the camouflage past of this insects.

In the paper published on June 24, the research team describes three groups of specimens that include the Chrysopidae (green lacewings) Reduviidae (assassin bug) and the Myrmeleontidae ( lacewings and owlflies).

The evolution of these insects is not well known in the science world, because of the shortage of material to study. These specimens are currently the oldest self-decorative insects, known by science despite one insect carved into Spanish debris found before Wang’s study.

Debris-carrying is a behavior in where insects harvest and carry exogenous materials and, according to the research team, it is one of the most fascinating and complex ways. Since it requires the ability to recognize, collect and carry materials over their body.

It turns out, these insects have their bodies adapted to their camouflage ability, some of them even have a natural structure on their back to carry the debris. The studied insects showed that some of them had long filaments on their backs to anchor the wreckage.

Ancient bugs covered themselves with debris, dirt, wood, leaves and even the exoskeletons of their preys to remain undercovered. Photo credit: Wang et al. Sci. Adv. 2016; 2 : e1501918 / Seeker

Nowadays, this type of natural structure is only seen in the chrysopid larvae a specimen that is believed to be a relative from this ancient samples.

“Only one group exhibits highly setigerous tubular tubercles on the thorax and abdomen, which are no longer seen in extant chrysopoid larvae. We don’t know why these morphological adaptations are absent in modern counterparts,” said lead researcher Bo Wang to the Christian Science Monitor in a statement.

Other advanced species also show similar behavior, such as the decorator crab, that surrounds itself with seaweed, algae, and rocks.  National Geographic, also reports that the larvae of caddisflies decorate itself with rock, sand, and plants. Meanwhile, the assassin bug wears a coat of dead ants as camouflage.

Researchers found that one of the ancient insects had the remains of different insects as camouflage. The published paper, explains that this larva had poison in its saliva and use it to inject their preys, sucking out of their juices and leaving a skeleton to use as protection, thanks to their long jaws.

The process of self-decoration is not a simple one, explains the paper, since it requires insects to recognize the natural materials that are efficient enough to use as coverage, then the species need to collect them and create their protection coat.

Researchers believe these camouflage skills were learned from a very young age since this massive coverage would be terrible for first flying insects. Also, the fossils found by Wang’s team belonged to juvenile specimens.

A new step for the science world

Although the evolutionary ladder of these insects is not clear to researchers, it is known that these self-camouflage habits were later seen in more modern insects. According to the Smithsonian’s report this ability “evolved separately in three groups of Cretaceous insects, that were later distributed in the world”.

Researchers now need to understand how did the evolutionary process happen, since it is not known if the ability of camouflage in modern insects evolved from this ancient specimens or if common insects developed this ability in a separate matter.

Source: Science Advances

Categories: Science
Maria Gabriela Méndez:
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