A new fossil discovery has suggested that stick-like insects have been disguising themselves as leaves for at least 126 million years.
According to National Geographic, the new discovery puts the stick insects cloaking mechanism before the arrival of flowering plants. The new fossils, found in modern-day Mongolia, are some of the earliest examples of stick insects.
"Our grand-cousins were already fooled by grand-cousins of stick and leaf insects 126 million years ago," study co-author Olivier Bethoux, of Sorbonne University in Paris, told National Geographic. "Our discovery demonstrates that plant mimicry by insects was achieved by various insect groups, including stick insects, before the rise of flowering plants."
The insect was named Cretophasmomima melanogramma ("ancient black-lined stick insect") and the study was published Wednesday in the journal PLOS One.
The most well known stick insect, of which there are 3,000 species, today is the praying mantis. The research suggests the insects developed the cloaking mechanism through evolution early on to avoid becoming prey to some of the earliest birds.
"This is yet more tantalizing evidence of early insect-plant coevolution," Sam Heads, a paleontologist at the University of Illinois at Urbana-Champaign who was not involved in the study, told National Geographic.
Study lead author Maomin Wang, of the Capital Normal University in Beijing, China, said the fossil places the earliest stick insect 77 million years earlier than previously thought, the Los Angeles Times reported. The researchers found the fossilized insect would have lived in the Cretaceous Jehol biota period.
"This new record suggests that leaf mimicry predated the appearance of twig and bark mimicry in Phasmatodeans," the study authors wrote. "Additionally, it complements our growing knowledge of the early attempts of insects to mimic plant parts."
Unlike modern stick insects, the ancient specimens were much more similar in size. The males were about two inches long and the females only bested that slightly, whereas modern insects' difference is much more noticeable.
