An endangered plant having the ability to hide from people searching for it seems like something out of a science fiction movie. But research published in Current Biology suggests that fritillary species may be using camouflage plant stealth to avoid being picked. ScienceNews describes how Fritillaria delavayi plants growing in easily accessible mountain sites blended in more with the background, becoming almost invisible to the human eye.
However, rather than camouflage plants pulling on camouflage pants, this is more an example of evolutionary pressure at work rather than wardrobe stealth. Hiding in plain sight means that the invisible fritillary survives to flower and thrive.
Commercial Harvest for Traditional Medicine
Fritillary plants grow in temperate areas of the world, from Europe through the Middle East and into Asia. These perennial flowering plants — specifically, their tiny bulbs — are highly valued in Traditional Chinese Medicine for cough and respiratory illness remedies. Smithsonian Magazine notes that as many as 3,500 bulbs are needed for one kilogram of the medicinal powder valued at around $480 USD. Now, researchers are noting how human harvesting activity has put pressure on these prized wild populations.
Researchers examining endangered fritillary populations had previously been baffled by how their study populations could disappear from one year to the next. However, with access to harvesting records, they began to understand the enormous pressure on certain sites from human foragers. The prized tiny plants grow on scree slopes in high-altitude areas, meaning that only easily accessible locations are harvested. This puts more pressure on these perennials to become a camouflage plant in order to live and grow another year.
Studying a Camouflage Plant in Its Natural Environment
Using spectrometry, the research team measured how closely the fritillary matched the rocky alpine meadows that they grew in. They found that in certain areas, more turned into a camouflage plant and blended into the background. At first, the scientists thought that this was probably due to predation, since most plant evolution is driven to avoid being an animal’s lunch. However, ScienceNews notes that when the team looked more closely, they couldn’t find any evidence of nibbling — a telltale sign that herbivore action is responsible for plant disappearance.
Science Alert reports that the researchers then turned to the human population for answers. From discussions with the local population, they were able to estimate how heavily certain areas were harvested. When they compared the spectroscopy data with the harvesting estimates, they found that plants in heavily harvested areas were more likely to show drab gray-brown coloring rather than the usual vibrant green.
The Benefits of Invisibility and Other Tales of Evolution
To the fritillary plants, being invisible is a huge benefit. By blending into the rocky scree surroundings, the plants avoid being noticed by people searching for them. In computer tests, the researchers found that it took people longer to spot the camouflage plant in an image.
Fritillary plants hiding in plain sight aren’t the first evidence of human activity influencing evolution, though it is an uncommon cause of adaptation. Dr. Bernard Kettlewell’s research on wing colorization published in Nature in 1955 showed that industrial pollution influenced Peppered Moth development. Where environments were covered in heavy black soot, those with black wings had an advantage over lighter-colored moths and could avoid predators to survive and breed.
Human Activity Shapes Evolutionary Adaptation
A 2005 paper published in the Proceedings of the National Academy of Sciences (PNAS) also describes how human pressure can impact plant adaptation. The research team that published the study investigated how harvesting for desirable species led to changes in the plant populations. Their data found that the highly prized Himalayan Snow Lotus decreased in height over a 100-year span. This was not seen in related species that were less threatened and not prized by collectors.
Another PNAS study suggests that humans as predators drive far greater rates of evolutionary change than other natural selection processes. Human harvesting drove more rapid phenotype changes in various wild populations than previously appreciated, leading the study’s authors to sound a note of alarm. This was also seen in a 2009 Evolutionary Applications study, which notes that fishing pressure has reduced the age and size at maturation for several heavily fished species at sea.
Human activity is driving a lot more than camouflage plant adaptation.
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