The hotness of chili peppers has always been something of an evolutionary mystery. A plant creates fruit in order to entice animals to eat and disperse its seeds -- so why would any fruit be painfully hot?
According to new research, the leading cause of seed mortality wild chili plants is a fungus called Fusarium. The fungus invades the fruits through wounds made by insects and destroys the seeds before they can be eaten and dispersed. Capsaicin, the chemical that makes the peppers...