Plant used in traditional Chinese medicine evolves to be less visible to humans

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Fritillaria delavayi in a population with low harvest pressure. Credit: Yang Niu

A plant used in traditional Chinese medicine has evolved to become less visible to humans, new research shows.

Scientists have discovered that Fritillaria delavayi the plants, which live on the rocky slopes of the Hengduan Mountains in China, most closely match their origins in areas where they are heavily harvested.

This suggests that humans are “driving” the evolution of this species into new color forms, as better camouflaged plants have a better chance of survival.

Fritillaria delavayi High harvest pressure

Fritillaria delavayi in a population with high harvest pressure. Credit: Yang Niu

The study was carried out by the Kunming Institute of Botany (Chinese Academy of Sciences) and the University of Exeter.

“It is remarkable how humans can have such a direct and dramatic impact on the coloring of wild organisms, not only on their survival but on their evolution itself,” said Professor Martin Stevens, of the Center for Ecology and Conservation at the Penryn campus of Exeter. in Cornwall.

“Many plants seem to use camouflage to hide from herbivores that might eat them – but here we see camouflage evolving in response to human collectors.

“It is possible that humans have driven the evolution of defensive strategies in other plant species, but surprisingly little research has examined this.”

In the new study, the researchers measured how well plants from different populations matched their mountain environment and how easy they were to harvest, and spoke to local people to estimate how much harvesting took place in every place.

They found that the level of camouflage in plants correlated with harvest levels.

In a computer experiment, more camouflaged plants also took longer to be detected by humans.

Fritillaria delavayi is a perennial herb that has leaves – varying in color from gray to brown to green – at a young age, and produces only one flower per year after the fifth year.

The bulb of the fritillary species has been used in Chinese medicine for over 2,000 years, and high prices in recent years have resulted in an increase in the harvest.

Fritillaria delavayi

Fritillaria delavayi in a population with high harvest pressure. Credit: Yang Niu

“Like other camouflaged plants that we have studied, we thought that the camouflage evolution of this fritillary was driven by herbivores, but we did not find such animals,” said Dr Yang Niu, of Kunming Institute of Botany.

“Then we realized humans could be the reason. “

Professor Hang Sun, Kunming Institute of Botany, added: “Commercial harvest is a much stronger selection pressure than many pressures in nature.

“The current state of biodiversity on earth is shaped both by nature and by ourselves. “

The research was funded by the Chinese Academy of Sciences and the National Foundation of Natural Sciences of China.

The article, published in the journal Current biology, is titled: “The commercial harvest resulted in the evolution of camouflage in an alpine plant. “

Reference: “Commercial Harvesting Has Driven the Evolution of Camouflage in an Alpine Plant” by Yang Niu, Martin Stevens and Hang Sun, November 20, 2020, Current biology.
DOI: 10.1016 / j.cub.200.10.078


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