Why some chillies are hotter than others – Australian Geographic.

A new study has shown that non-pungent (mild) chillies have a different advantage: they can thrive when water is scarce.

Chillies evolved their spiciness to deter a fungus that feasts on chilli flesh and seeds. But it turns out that investing heavily in defence is not always the best option. In dry environments, where plants have to be water efficient, it’s the chillies without heat that flourish.