Scientists have discovered that stick insects keep evolving to get the same weird body plans over and over again. This evolutionary blueprint has enabled researchers to predict the next developments of creatures.
Researchers have identified only 20 different body types that evolved independently from hundreds of different species of stick insects. These body types include the “tree crayfish” which has crayfish-like features; “bark huggers” who blend in with the tree; and “big-headed sticks,” which have huge jaws or mandibles.
The same body types continue to appear all over the planet because many strains of stick insects have colonized similar environments and need the same features to survive. These similarities allow researchers to predict the evolution of stick insects, even when the creatures evolved independently from each other for tens of millions of years, according to a new study published Monday (Dec. 23) in the journal. With people.
“What we’re delving into here is the predictability of evolution,” said the study’s first author Roman Boisseaua postdoctoral researcher studying stick insect evolution at the University of Lausanne in Switzerland, told Live Science. “If you have a similar strain invading a very similar environment, you can actually predict where it will go.”
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When different organisms develop similar traits, it is called allotropy Convergent evolution. Previous research has highlighted some examples of convergent evolution in stick insects. For example, a 2008 study published in the journal Proceedings of the Royal Society B Found that Lord Howe Island, Australia, sticks to insects (Australian dura) – once It is believed to be extinct – Independently evolved the same “tree crayfish” form as the New Guinea spiny devil’s stick insects (Eurycantha).
However, Boisseau noted that no one has performed a large-scale study of convergent evolution across multiple different lineages of stick insects. To understand how common convergent evolution is, the team measured and compared features of 1,359 stick insects from 212 species.
Boisseau and his colleagues found that 20 somatic striatums—out of a total of 21 striatums—had evolved at least twice in different regions, and that the broad, stick-like appearance had evolved at least 10 separate times.
“In all these regions of the world, many different body shapes appear to have evolved repeatedly independently,” Boisseau said.
Camouflage stick insects
Habitat was a major factor in the evolution of body plans. Stick insects use camouflage as a main line of defense against predators, so when predators and habitats are similar, the same type of camouflage is required for survival, Boisseau noted.
The team also looked at how closely related the different stick insects are. A pattern emerged: stick insects with the same body plans shared an ancestor, even though that ancestor looked very different. In other words, stick insects followed similar evolutionary paths once they separated from each other.
“They basically tend to follow the same path,” Boisseau said. “This is probably related to the fact that they are genetically more similar. It is likely that the same genes or the same mechanisms are being repurposed in these closely related species.”
Boisseau and his colleagues will now study stick insect genetics more closely to find out what drives convergent evolution at the molecular level.
