The evolutionary purpose of rubber, and the reason why it has appeared independently in plants as diverse as trees, guayule and dandelions, is that it gums up the mouthparts of herbivorous insects.

• 橡胶形成的进化目的，以及橡胶之所以分别出现在橡胶树、银胶菊、蒲公英等各种各样的植物中的原因，在于它能黏住食草动物的口器。