A perennial herb called Fritillaria delavayi adorns China's rocky Hengduan mountains with colors varying from grey to brown to green and produces a precious bright yellow flower after completing its fifth year.
However, like many other species, it has been going through the onslaught of humans who harvest it to make traditional Chinese medicine. For more than 2,000 years, the bulb of the fritillary species has been used to treat ailments of the lungs with high prices in recent years leading to an increase in harvesting.
Now, a paper published in the journal Current Biology shows an unusual occurrence of natural selection of this species due to humans: As commercial harvesting has intensified, Fritillaria delavayi has become almost invisible in order to survive.
The plant matched the rocky exterior
An international team of botanists measured a few things: First, they looked at how different populations of Fritillaria delavayi match their environment and how easy they were to collect. Then, they spoke to the town people to estimate the harvesting that took place in those locations.
They saw that the level of camouflage in the plants correlated with harvesting levels, and a computer experiment further showed that more-camouflaged plants took longer to be detected by people, increasing their overall survival, Forbes reports.
In areas where commercial harvesting was more intense, Fritillaria delavayi evolved to produce grey and brown leaves and flowers that couldn't be easily detectable by pickers. Moreover, the color of the plant's leaves had become more camouflaged, making it partially invisible by matching the slate-like metamorphic rock on which they grow.
Areas in which were too high to be visited regularly by the harvesters, the plant maintained its green leaves and the yellow flower that was originally seen in naturally occurring populations, per Phys.
Professor Martin Stevens, of the Centre for Ecology and Conservation on Exeter's Penryn Campus in Cornwall, stated this was extraordinary. "It's remarkable to see how humans can have such a direct and dramatic impact on the coloration of wild organisms, not just on their survival but on their evolution itself," he said.
"Many plants seem to use camouflage to hide from herbivores that may eat them—but here we see camouflage evolving in response to human collectors. It's possible that humans have driven evolution of defensive strategies in other plant species, but surprisingly little research has examined this."
Professor Hang Sun, of the Kunming Institute of Botany, also added that commercial harvesting is a "much stronger selection pressure than many pressures in nature." Shining the light on humanity's unrelenting shaping of nature, Sun said, "The current biodiversity status on the earth is shaped by both nature and by ourselves."