schki bum

Why are hot peppers hot? I know it is because of the capsaicin in them, but why do the plants make capsaicin? What benefits do the plants get out of it?

It's a silly question, I know. But I've got a big cayenne plant in my living room, and I have to wonder every time I walk past the thing.

LeftCoast

Disclaimer: I am not a biologist/botanist nor do I play one on TV.

Most obvious reason I can think of is that the peppers are in reality the seed pods for the various plants and the capsaicin is probably a mechanism to make the pods unpalatable to most grazing animals. The ones with the real heat have probably been locked into an arms race with some species that has evolved a taste for or at least a resistance to the capsaicin.

NonHomogenized

I can think of two possibilities, offhand.

1 (which consider more likely). The hot flavor makes animals less likely to eat them, and, therefore confers a survival benefit

2. The flavor makes some animals more likely to eat them, in which case the seeds would end up in the stool, allowing for plant dispersal.

I'll leave it up to someone with resources, and the patience at the moment to use them, to find out which, if either, is correct.

FoE

Obviously god made them that way. God likes Thai food.

Derec

Of course that explains the wild forms. However the peppers we use now in the food have high levels of capsaicin because they were selectively breeded for it.

UMoC

markfiend

IIRC capsaicin is a natural antiseptic, the plant's defence against bacterial and fungal infections.

My information comes from a TV food program, so may be limited in accuracy.

Nickle

Sorta a little of both. The peppers are just a little picky when it comes to who is doing the eating. The capsaicin favors animals that are better at dispersal by dicsouraging the poorer dispersers.

This article in Nature studied a pepper in Arizona, and found that the local curve-billed thrashers (a bird, not a muscle car) love 'em. The thrashers also do a better job of dispersal than the local mammals. Good ol' evolution in action.

Coragyps

I read an article a couple of years ago that talked about how birds, in general, don't have taste receptors at all for capsaicin, so they don't find peppers hot at all. Mammals do have receptors. Also, birds have no teeth to chew up seeds, and mammals do. So, as Nickle and N-H said, it's coevolution in action: a smokin' serrano pepper will deter mice, but attract birds, which will deposit seeds around in little packets of fertilizer.

jayh

There are commercial wild bird foods which coat the seeds with capsaicin to discourage squirrels from eating them.


j

demoninho

i'd like to add a question; does capsaicin only cause pain or does it actually do some damage to the gastro-intestinal tract?