Bugs 145;put the heat146; in chilli peppers

According to them, the spiciness is a defense mechanism which some peppers develop to suppress a microbial fungus that invades through punctures made in the outer skin by various insects.

The fungus, from genus Fusarium, destroys the plant8217;s seeds before they can be eaten by birds and distributed.

8220;For these wild chilies, the biggest danger to the seed comes before dispersal, when a large number are killed by this fungus. Both the fungus and the birds eat chilies but the fungus never disperses seeds 8212; it just kills them,8221; said researcher Joshua Tewksbury of the University of Washington.

Fruits use sugars and lipids to attract birds that will scatter the seeds. But insects and fungi enjoy sugars and lipids too, and in tandem, they can actually be fatal to a pepper8217;s progeny.

However, the researchers found that the pungency in hot chilies acts as a unique defense mechanism 8212; the pungency comes from capsaicinoids, the chemicals that protect them from fungal attack by slowing microbial growth, the 8216;Proceedings of the National Academy of Sciences8217; journal reported.

For their study, the researchers collected chilies from seven different populations of the same pepper species spread across 1,000 square miles in Bolivia.