Fruits can be classified into "ripe-type fruits" (bananas, apples, peaches, etc.) that continue to mature after harvesting and "non-ripe-type fruits (grape, strawberries, cherry, etc.) that do not mature after harvesting. Although ripened and non-ripened types have been studied for many years as a very important property in horticultural science, strangely, their role is hardly known ecologically, and why ripening is in the first place. It was unclear if there were typed and unripe fruits.
This time, Assistant Professor Yuya Fukano of the Graduate School of Agriculture and Life Sciences, the University of Tokyo, focused on the fact that fruits evolved as a reward for animals (seed dispersers) who carry seeds, and ripened and non-ripened types. It was hypothesized that the difference between the two was the result of adaptation to different types of seed dispersers.Then, in order to test this hypothesis, a literature survey was conducted on 80 kinds of fruits to find out what kind of animals each fruit was eaten and seed-dispersed in its natural state.
As a result, it was found that the ripened fruits tended to be sprayed on the terrestrial wandering animals, and the non-ripened fruits tended to be sprayed on the arboreal animals.This is because the nature of ripened fruits, whose maturity accelerates after fruit fall, has evolved to allow animals roaming the ground, such as tanuki and inoshishi, to eat the fruits. Considering that the nature of ripe fruits has evolved to be eaten by tree animals such as birds and bats, it is consistent with the previous hypothesis.
Furthermore, it was also found that the ripened fruits had large seeds and tended to have green or brown skin, and the non-ripened fruits had small seeds and tended to have red or black skin.These characteristics are said to be consistent with those preferred by terrestrial wandering animals and arboreal animals, respectively.
This result is a new discovery suggesting that the ripening / non-ripening nature was born from an evolutionary interaction with the type of seed disperser.
Paper information:[Biology Letters] Evolutionary ecology of climacteric and non-climacteric fruits
