UNIVERSITY OF EXETER
IMAGE: FRITILLARIA DELAVAYI IN A LOW HARVEST POPULATION View More CREDIT: YANG NIU
A plant used in traditional Chinese medicine has evolved to be less visible to humans, new research shows.
Scientists found that Fritillaria delavayi plants that live on rocky slopes of China's Hengduan Mountains are best suited to their background in areas where they are heavily harvested.
This suggests that humans “drive” the evolution of this species into new color forms, as better camouflaged plants have a higher chance of survival.
The study was carried out by the Kunming Institute of Botany (Chinese Academy of Sciences) and the University of Exeter.
"It is remarkable to see how humans can have such a direct and dramatic impact on the coloration of wild organisms, not only on their survival but also on their development themselves," said Professor Martin Stevens of the Center for Ecology and Conservation at Exeters Penryn Campus in Cornwall.
“Many plants seem to use camouflage to hide from herbivores who may eat them – but here we see camouflage evolving in response to human foragers.
"It is possible that humans advanced defense strategies in other plant species, but surprisingly little research has investigated this."
In the new study, the researchers measured how closely plants from different populations fit their mountainous environment and how easy they are to collect, and spoke to the locals to estimate how much harvest there was at each location.
They found that the level of camouflage in the plants correlated with the level of harvest.
In a computer experiment, it also took longer for more camouflaged plants to be discovered by humans.
Fritillaria delavayi is a perennial herb whose leaves vary from gray to brown to green when young, and after the fifth year produce a single flower per year.
The mother-of-pearl onion has been used in Chinese medicine for more than 2,000 years, and high prices in recent years have resulted in an increased harvest.
"Like other camouflaged plants we examined, we thought the evolution of camouflage for this mother-of-pearl fish was driven by herbivores, but we did not find any such animals," said Dr. Yang Niu from the Kunming Institute of Botany. "Then we realized that humans could be the reason."
Professor Hang Sun of the Kunming Institute of Botany added, “Commercial harvesting is much more selective pressure than many pressures in nature. "The current biodiversity status on earth is shaped both by nature and by ourselves."
The research was funded by the Chinese Academy of Sciences and the National Natural Science Foundation of China.
The paper, published in the journal Current Biology, is entitled, "The commercial harvest has fueled the development of camouflage in an alpine plant."