Eli5: why do chilli plants turn red to attract animals to disperse seeds but also produce the spicy chemical to put them off?

Question

Eli5: why do chilli plants turn red to attract animals to disperse seeds but also produce the spicy chemical to put them off?

In: 6541

Answer 1

Plants make fruit so that animals eat the fruit and then poop out the seed somewhere far away from the plant. Birds are much better at spreading seeds over large distances than mammals. So what the pepper plant does is make a substance, capsaicin, that makes mammals feel burny and not want to eat the fruit, but doesn’t affect birds at all. So mammals will skip eating the hot peppers, but birds will eat them just fine, and the plant gets maximum seed spread at the lowest cost.

Humans were an unexpected development, but it worked out extremely well for the species.