For thousands of years it has been delicious Fritillaria delavayi has grown slowly on the rocky slopes of the Hengduan Mountains of China and produces a light green flower after its fifth year.
But the conspicuous little plant has a deadly enemy: people who harvest the flower for traditional Chinese medicine.
As commercial harvesting has intensified, Fritillaria delavayi has disappeared ̵
Researchers have discovered that the color of the plant’s leaves has become more camouflaged – similar to the background stones on which they grow – in areas where there is more harvest pressure from humans.
“Like other camouflaged 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 Kunming Institute of Botany and co-author. of the study in Current Biology. “Then we realized that humans could be the cause.”
In a study by the Kunming Institute of Botany (Chinese Academy of Sciences) and the University of Exeter, researchers measured how closely plants from different populations matched their mountain environment and how easy they were to collect, and interviewed local people to estimate how much harvest took place every place.
In a computer experiment, it was found that humans took more time to discover the more camouflaged plants, suggesting that humans are driving the rapid evolution of this species into new color forms because better camouflaged plants have a greater chance of survival.
Fritillaria delavayi is a perennial herb that grows leaves at a young age before producing a single flower after its fifth year each June. The bulb from fritillary species has been used in traditional Chinese medicine for more than 2,000 years, but high prices in recent years have led to increased harvests.
“It is remarkable to see how humans can have such a direct and dramatic impact on the staining of wild organisms, not only on their survival but also on their evolution,” said Prof Martin Stevens, Center for Ecology and Conservation at the University of Exeter. “Many plants seem to use camouflage to hide from herbivores who might eat them – but here we see camouflage evolving in response to human collectors.
“It is possible that humans have driven the development of defensive strategies in other plant species, but surprisingly, little research has examined this.”