Surprisingly few insects live in the ocean, and we may finally know why: ScienceAlert

Insects were present for approximately 480 million years agoWhich gives them plenty of time to crawl, crawl, burrow and float to the surface of our planet.

Well, pretty much everywhere. Surprisingly few species live in the oceans, and scientists have been trying to figure out why.

A research team from the US and Japan recently proposed an intriguing hypothesis about this, claiming to have discovered a “simple explanation for a long standing question”.

They suggest one enzyme which helps insects to harden their intestines, named multicopper oxidase-2 (MCO2), which is why it is rarely found in the marine environment but works well on land.

said biologist Tsunaki Asano of Tokyo Metropolitan University, who led the team appears previously Insects have evolved a special mechanism to harden their hard outer layer using molecular oxygen and MCO2.

Now, Asano and colleagues explain in A published magazine How it puts different creatures in the oceans at a disadvantage but helps them. This is mainly due to the abundance of chemicals in each environment and the lightness of the insects’ exoskeletons.

“The emergence of insects is an important event in the evolution of life on Earth,” the team said. writing“It highlights a major adaptive expansion of organisms in a new terrestrial ecosystem.”

Among the most successful creatures on the planet, insects are the largest group in the Phylum arthropods, which contribute the largest biomass of all land animals. They play an important role in maintaining the balance of life on Earth.

Modern perspectives molecular Evolution revealed that insects And oysters (which live mainly in the oceans) belong to the same branch, the so-called crustaceans.

Although insects They branched off from their crustacean ancestors and evolving wildlife patterns, both of which remain exoskeletons Made of wax and steel skin Carbohydrates are called chitin.

This epidermis is a protective layer that lines the surface of the body, keeping moisture inside the epidermis and germs out, just like our skin. More than just a pretty bag, it also protects the body from external mechanical forces and helps maintain body shape and movement, acting as an external scaffolding.

However, while crustaceans primarily use calcium from seawater to harden their scales into shells, insects use molecular oxygen to transform their cuticles into durable envelopes for their organs through the mediation of MCO2.

Asano and his colleagues say that the presence of oxygen in the air makes the earth more attractive to insects. The sea is now a harsh place for them because there is not enough oxygen, not to mention that it already shelters and feeds many of the most adapted species.

To the benefit of the insects, their shell becomes harder and drier through the MCO2 pathway, creating a protective biomaterial while remaining somewhat light like a feather. This is a stark distinction from crustaceans, whose shell is denser due to a direct proportion between shell density and level of calcification, which spoils life in the air.

Insects may have evolved their ability to climb plants, hover, and eventually fly through MCO2 locomotion, allowing them to move more easily and fill previously unoccupied ecological niches.

The team believes that MCO2 may be what makes insects unique; as they are say in their diary“No MCO2, No Bugs.”

Explaining in more detail the specificity of insects, Asano and his team indicates that: “Other arthropods, including our closest insect relatives, and non-insect hexapods such as the springtail and two-pronged bristle-tail, lack the MCO2 genes.”

The researchers note that insects aren’t the only arthropods that have adapted to life on land, so MCO2 isn’t a necessary condition for successfully leaving your ocean and settling on land.

But the unique way the insects’ scales are made provides a wealth of insights into how they evolved to survive in the terrestrial environment.

“If insects had not acquired an MCO2-mediated system, insect development and success would have been dramatically different from what we currently observe,” the team said. And he concludes.

“We hope to have further discussion of insect evolution and landing based on this view.”

Review posted on Physiological entomology.