快猫短视频

Dozens of plants on a small Japanese island may have shrunk themselves to avoid hungry deer 鈥� suggesting that persistent pruning by herbivores could drive the evolution of dwarf plants.

Miniaturised plants are found all over the world, says at Tohoku University in Japan, but these stubby flora are usually a reaction to environmental factors such as cold, dry or windy conditions.

The alpine reaches of Yakushima Island in southern Japan host more than 80 plant species that are a mere fraction the size of their close relatives on the larger Japanese islands. This phenomenon has long puzzled scientists, says Takahashi.

In 2017, he and his colleagues visited Yakushima Island and noticed tiny plants next to standard-sized species that are unpalatable to deer. The island hosts between 12,000 and 16,000 Japanese sika deer (Cervus nippon yakushimae). Compared with Japan鈥檚 mainland and other islands, Yakushima Island鈥檚 deer density is five to 10 times higher due to a lack of local predators, says Takahashi.

The team measured the dimensions of 40 pairs of closely related mountain plant species, each containing samples from Yakushima Island and from the mainland. Of the 40, 33 pairs differed greatly in size, with some Yakushima plants reaching just one-tenth the size of their mainland counterparts. Of these pairs, 28 are appetising to deer. The researchers analysed differences in precipitation, sunlight and nutrient levels between the island and mainland but found that none could account for the tiny plants 鈥� they suggest it is the appetite of the island deer that drove the plants鈥� evolution into dwarves.

快猫短视频s have previously linked grazing to dwarf plant evolution, but Takahashi and his colleagues argue they have offered the first evidence of herbivores pushing many plant species to independently evolve small size.

Growing shorter and smaller may offer advantages in a deer-dense environment. It is inefficient for deer to munch on tiny plants, says Takahashi. For instance, shorter plants yield less food per bite.

Takahashi and his colleagues analysed the plants鈥� DNA to reconstruct their evolutionary history and found the dwarf plants evolved over tens of thousands of years, possibly from sustained pressure from sika deer.

These findings show 鈥渢he strength of evolution, where it鈥檚 shaping not just one particular organism, but whole suites of organisms are travelling the same evolutionary pathways鈥�, says at Victoria University of Wellington in New Zealand.

In the future, Takahashi says he aims to investigate whether shared genes lead to dwarfism across distantly related species of plants 鈥� which may help researchers better grasp how unrelated organisms converge on similar evolutionary outcomes.