PHOTO / CHINA
Grasshoppers sprint or run marathon, depending on family size: study
Published: Jan 06, 2022 08:42 AM
A boy clears locusts from a rice field during a locust campaign in Madagascar, May 8, 2014.(Photo: Xinhua)

A boy clears locusts from a rice field during a locust campaign in Madagascar, May 8, 2014.(Photo: Xinhua)


 
Some grasshoppers are long-distance runners, flapping their wings constantly for as long as 10 hours, while others shoot ahead and get exhausted quickly, according to a new study by Chinese researchers.

The study found that grasshoppers are not born to be marathoners or sprinters but it all depends on whether they grow in a big family.

Researchers from the Chinese Academy of Sciences (CAS) studied the flight capacity of migratory locusts and solitary locusts, and have found that a gregarious life in childhood enables grasshoppers to take a long-distance but relatively slow flight.

On the other hand, those living alone are not weak in flying as previously thought. They turn out to be good at dashing but lack stamina, according to the study published in the Proceedings of the National Academy of Sciences (PNAS).

According to the researchers, these solitary grasshoppers are preoccupied during their entire life with finding mates and escaping predators, and they don't have to migrate. Therefore, their flying muscle adapts to a metabolic pathway that fuels swiftly and generates more reactive oxygen species (ROS). Such a mechanism restricts them from flying far.

By contrast, in a populous, competitive group, grasshoppers have to go on a long journey to secure sufficient food and a good spawning bed, so they metabolize in a way that checks the sprint ability in exchange for endurance.

Migratory locusts can fly in legion for more than 2,000 kilometres in one generation, said Kang Le, a researcher with Beijing Institutes of Life Science under CAS, who is involved in the study.

Kang's group interfered with the grasshopper's RNA that is known to repress the metabolic activity and the initial flight speed of solitary locusts was markedly reduced.

Besides, increasing the ROS level remarkably inhibited the long-distance flight of gregarious locusts, according to the study.

The trade-off between velocity and sustainability can be reshaped quickly depending on the pest's population density, the researchers said.

The study revealed that grasshopper's flying strategies are plastic to the survival stress, offering a new understanding of the adaptive behaviours of the species.

The findings can be deciphered by drawing a comparison between the muscular contours of a bodybuilder and a long-distance runner -- training rather than genes makes the difference.