UNIVERSITY OF PRACTICE
IMAGE: FRITILLARIA DELAVAYI IN POPULATION WITH LOW HARVEST WEIGHT see more CREDIT: YANG NIU
A plant used in traditional Chinese medicine has evolved to become less visible to humans, new research shows.
Scientists found that the plants of Fritillaria delavayi, which live on the rocky slopes of China’s Hengduan mountains, closely match their backgrounds in areas where they are heavily harvested.
This suggests that humans are “driving” the evolution of this species to new color forms because better camouflage plants have a higher chance of survival.
The study was conducted by the Kunming Institute of Botany (Chinese Academy of Sciences) and the University of Exeter.
“It’s amazing to see how human beings can have such a direct and dramatic impact on the coloring of wild organisms, not only on their survival but on their own evolution,” said Professor Martin Stevens, of the Center for Ecology and Conservation at the Penryn Exeter Campus 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.
“Humans may have driven the evolution of protective strategies in other plant species, but surprisingly little research has explored this.”
In the new study, the researchers measured how closely related plants were to their mountain environment and how easy they were to collect, and talked to locals to estimate how much harvest had taken place in each location.
They found that the level of camouflage in the plants was related to harvest levels.
In a computer experiment, it took longer for more camouflaged plants to be found by humans.
Fritillaria delavayi is a perennial herb whose leaves – ranging in color from gray to brown to green – is young, and produces a single flower the year after the fifth year.
The bulb of the fritillary species has been used in Chinese medicine for more than 2,000 years, and high prices in recent years have led to increased harvests.
“Like other camouflage plants we have studied, we thought the camouflage evolution of this fritillary was driven by herbivores, but we did not find such animals,” said Dr Yang Niu, from the Kunming Botanical Institute. “Then we realized that humans could be the reason.”
Professor Hang Sun, from the Kunming Institute of Botany, added: “Commercial harvesting is a much stronger choice pressure than many in nature. “The current status of biodiversity on earth is shaped by nature and by ourselves.”
The research was funded by the Chinese Academy of Sciences and the National Natural Science Foundation of China.
The title of the paper, published in the journal Current Biology: “Commercial harvesting has driven the evolution of camouflage in an alpine plant.”