E It has also been proposed that trees may produce vivid red colours to convince herbivorous insects that they are healthy and robust and would be easily able to mount chemical defences against infestation.

E 也有人提出，树木可能会产生鲜艳的红色，以使食草昆虫相信它们是健康和强壮的，并且很容易能够对侵扰进行化学防御。

D Some theories about anthocyanins have argued that they might act as a chemical defence against attacks by insects or fungi, or that they might attract fruit-eating birds or increase a leaf's tolerance to freezing.

D 一些关于花青素的理论认为，它们可能作为一种化学防御剂来抵御昆虫或真菌的攻击，或者它们可能会吸引食果鸟类或增加叶子的抗冻能力。