Chilis have their reasons the birds know not of?

Cecil's Columns/Staff Reports
1

An insignificant quibble. The answer to the chili question says in part:

``The reason chilies incorporate capsaicin in their fruits . . . seems to be to ensure that their seeds are dispersed properly. When small birds consume the fruits of wild peppers the seeds pass through the gut undigested and, due to the birds’ flight range, are deposited in distant places where they can grow with less competition. If the fruits were consumed by larger mammals the seeds would either be digested, or deposited much closer to the parent plant. Studies have shown that the seeds of wild peppers are in fact dispersed almost exclusively by birds.’’

Most probably, niether the chili (“if I make an unpleasant chemical I will ensure my seeds are better dispersed”) nor the bird (“if I eat this yummy chili I will help disperse its seeds”) are reasoning here. The “reason” chili seeds are dispersed by birds is that birds are immune to the capsaicin.

The putative existence of a being or beings with one or many reasons to make chilis and birds the way they are is a topic for a different time and place.

2

Well, this sure turned my capsical thinking around. Jethro Kloss’s natural health book from the 1930s, Back to Eden, has a long article on the medicinal benefits of Capsicum (which he calls the “African bird pepper”).

Kloss relates that the Mexicans eat so much of it that “their bodies become thoroughly impregnated with it” and if one of them happens to die on the desert, “the vultures will not touch the body on account of it.”

Kloss was from Wisconsin, and plainly his idea of life and death in Mexico was based on nothing more than hearsay. Now, thanks to the Straight Dope, it’s clear that there is no scientific basis for vultures avoiding the chili-eating hombres. Must be just another leyenda urbana.

3

I have a friend who swears that when she plants regular peppers and hot peppers next to each other in her garden, the regular peppers take on the “heat” from the hot peppers. Has anyone ever heard of this? How would THAT happen?

4

BTW, the “guest contributor” who wrote this staff report is our own “Colibri” on the message board.

  • Jill
5

Congratulations on your moment of SD fame, Colibri. I especially enjoyed “enough incendiary material to vaporize a camel”. That’s fine writing.

6

Yeah, that’s fine writing, but this:

“) hokey smokes, Josephine, what do you suppose that will do to their tiny bungholes tomorrow morning?”

is sheer poetry.

7

“Moment” of SD Fame? Here’s hoping he writes a lot more of them!

8

Apart from the evolutionary determinism quibble raised by Tom, that was a damn fine Mailbag Answer - spiced with enough extraneous information and humour to whet the appetite for more. (MSG receptor identified?. Is that the same as the Japanese “meaty flavour” one?)

Nice one, Colibri.

9

Just checking. Are you denying that it might be possible that a selection process could have occurred in which plants with a fruit that deterred mammals but not birds had a reproductive advantage over those which were consumed equally by both?

It seems entirely possible that that is what happened - and in many evolutionary biology articles I have seen “wanted”, “tried”, and “causes” as short hand for the fact that a significant enough a benefit was being gained as to cause a selection process for that benefit. Some books popularizing the subject have even had to explain this for the new reader.
If Colibri was using incorrect terminology, he’s not alone.

10

Just a comment about birds eating certain things which makes them less attractive to predators.

There is one bird which does just this.It’s the largest of the grouse family and would otherwise be a prime dinner candidate.

The Capercaillie lives in Northern Europe and is the national bird of the Scottish Highlands(some might argue that the Scots national bird is the Golden Eagle but I digress)
The diet of the Capercaillie consists largely of the shoots of pine trees, and everyine knows of course that turpentine originally was made from this source.
The flesh of this bird is not at all pleasant to eat because of the strong turps taste.

Foxes, mink and stoats will take them but usually en-extremis.Most of their problems are, as usual, man-made.

This website is overly pessimistic but has some good information.

http://www.treesforlife.org.uk/tfl.capercaillie.html

Where’s Wood Thrush and Brachy when you need them the most ? :slight_smile:

11

The nit-picking aside, that has to be one of the most scientifically-written-but-understandable-by-a-high-school-dropout articles I have ever seen. Nomination for threadspotting here

12

Obviously you aren’t from the south- otherwise ya mama woulda told you never to plant your sweet and hot peppers together. As we’re told in Colibri’s excellent article, peppers are the fruit of the plant: they result from pollination and are therefore combo-platters of the parent’s DNA. ‘Heat’, being the dominant trait, ends up being expressed after cross-pollination!

13

[[‘Heat’, being the dominant trait, ends up being expressed after cross-pollination!]]

Are we sure about this?

14

It sounds reasonable: Production of a substance is usually dominant over non-production of same substance. The reason that a bell produces negligible heat is probably that it lacks the production genes, not that it has suppressor genes.

15

Well, actually no, I’m not positive that ‘heat’ is the dominant trait- or that it is controlled by such a simple mechanism. I was only speaking relatively. I do know that sweet peppers were derived only by selective breeding to reduce their amount of capsaicin. Cross pollination with a hotter variety of pepper would then throw in genes for a greater production/expression of ‘heat’ lipids, resulting in a hotter than normal fruit.

Also, an informal surf of the web indicates that this is a hot topic of debate- I slay me! Several ‘experts’ are at polar extremes as to whether the above is even possible. But honey, I’ve tasted it!

16

[QUOTE]
*Originally posted by Kyberneticist *
**

Not in the least; that’s exactly what seems to have happened here.

Me too. Insofar as those articles give the people who write them an air of explaining things that can’t be explained with our present knowledge such as why birds and chilis are the way they are, they only cause confusion.

17

First of all, let me apologize for not responding to the comments on my article sooner. Due to the Thanksgiving holiday I was out of town and unable to reply. (Not only was my brother’s modem busted, my nephews would never have let me near the computer anyway.)

Regarding the OP and subsequent comments related to it, of course I was using the word “reason” as shorthand, in the sense of “cause.” (Perhaps I should qualify that as “apparent cause” to avoid further quibbles.) Of course I did not intend to imply that either birds or chilies were “reasoning” in any way. In a scientific context I would have phrased it more precisely. What I meant to indicate is that this is the most commonly accepted scientific explanation for why chilies contain capsaicin. I have no inclination to start a discussion of the validity of evolutionary theory here. That sort of thing is better addressed in Great Debates.

In an adaptationist/selectionist/evolutionary framework, chili plants manufacture capsaicin because those that do ultimately leave more offspring than those that don’t. The reason, in fact, seems to be because their seeds are dispersed more widely and effectively by birds than they would be by mammals. A relevant recent article is: Tewksbury, J.J., G.P. Nabhan, D. Norman, H. Suzan, J. Tuxill, and J. Donovan. 1999. In situ conservation of wild chiles and their biotic associates. Conservation Biology 13:98-107. In field tests in the Sonoran desert of Arizona the authors found that birds (in this case Mockingbirds and Thrashers) effectively dispersed chili seeds to suitable germination sites (relatively moist and shaded) under other plants with fleshy fruits attractive to birds, notably hackberry. In feeding tests, small mammals rejected chilies while birds accepted them. While in this particular case the dispersal capabilities of mammals could not be tested, because they reject chilies almost completely, there have been numerous studies documenting the differential dispersal capabilities of different classes of animal consumers and how that affects seedling survival. However, I should add that, although many fruits seem to be “designed” to attract different categories of dispersers (e.g. mammals vs. birds), depending on the dispersal requirements of the plant, chilies seem to be one of the few plants that actually repel unsuitable dispersers. (IMPORTANT NOTICE: Please place quotation marks around any of the words in the previous paragraph you find debatable).

I limited my explanation to the scientific one because that is the only “reason” that is really open to experimental testing. If you want other “reasons,” I would refer you to various Native American creation tales. My favorite is that of the Cora, of Mexico’s west coast. Narama, the first man, jumped on a banquet-table at a feast. At that moment his testicles changed into chili pods, and he shook the spice onto the plates of the other diners. Momentarily taken back (I’m sure I would be), the others sampled the condiment and loved it.

Yes, technically called “umami,” the receptor responds to monosodium glutamate. Check:

Besides sweet, sour, etc., is there a fifth taste sensation, “umami”?

Regarding casdave’s post about distasteful birds, I believe there are a number of others besides the Capercaillie, but I haven’t tried to dig into this topic in depth yet. Incidently, besides the Pitohui, which I mentioned in the article, it has just been determined that yet another New Guinea bird, the Ifrita, also contains neurotoxins.

Regarding the issue of bell peppers picking up “heat” from nearby hot peppers, it makes sense to me that crossbreeding bell peppers with varieties containing capsaicin would result in the offspring being hot. But I’ll take gonz007’s word for it that the controversy isn’t resolved, as I haven’t had a chance to look into this myself.

And thanks very much to all for all the kind words on the article. I am working on a few others.

18

Thanks for the info re umami. And sourced from the Master as well. I should have looked before I asked, shouldn’t I!

19

I mentioned this topic to my friend from Louisiana, and he told me that when turkeys are allowed into the chili pepper patch, the result is that their meat is so hot you can’t eat it!

Come to think of it, that would be another way to cook the spicy Mexican turkey recipe mole con pavo. You could just cook chili-fed turkey and leave out the chilis.

20

That’s an interesting observation, ishmintingas. In the final paragraph of the article, I was referring to a study published in the ever-popular journal Poultry Science: Hirschler et al. 1995. Flavor evaluation of light and dark meat from broilers fed capsaicin, (74:205-207). While I haven’t been able to get hold of the article itself, the abstract indicates that human taste testers were unable to detect any difference in light or dark meat from chickens that had been fed capsaicin vs. those that had not. Maybe turkeys are different. As we know from the effects of a chili dinner the next day, humans at least do not seem to break down capsaicin very effectively in the digestive system. And I don’t know how well capsaicin would be absorbed intact in the small intestine of either mammals or birds, which would be necessary to have it incorporated in the flesh.

In any case, maybe your friend should patent those turkeys. I’d certainly buy one.

George Angehr