termites are able to digest wood due to a mutualistic relationship w/ microbes in their stomachs that are able to digest cellulose. the termites get the ability to eat wood and the microbes get free meals. but how do the microbes get in the termite’s stomachs in the first place?
and could those same microbes live in a person’s stomach? would that mean we could eat wood if we chopped it up real fine?
My first WAG was going to be straight coprophagia, which is at least partially correct, but as explained inthis grad student blurb, feces is a common building material used by termites, so they likely populate their guts with bacteria in their day to day activities, especially when eating foods that have been brought into the structure. Interestingly, the bacterial residents in the guts of different colonies seems to be involved in a mechanism of detecting whether or not a termite is friend or foe:
To attempt an answer the second part of your question, there are many other differences between human and termite guts and digestion than the presence or absence of certain bacteria. In order to evolve such a symbiotic relationship, our gut would have to evolve such that it was hospitable to our new microscopic friends while being able to absorb the converted fuels (which might come with some not so pleasant consequences, like having to carry our stomachs around in a wheel barrow to allow for enough bacteria to make the whole symbiosis thing work)…and we’d have to live in proximity to species of bacteria that would fit the bill…and they’d have to evolve to withstand the living environment of our guts…and that’s just naming a few of the challenges that would be faced by natural selection or engineering off the top of my head.
The microbes are primarily located in the hindgut, not in the stomach.
Termite nymphs are fed by the adults via regurgitation. Being fed vomit from another insect innoculates the newly hatched nymph with a full compliment of micorbes within minutes of hatching.
Plant eating mammals such as cattle, horses and beavers also rely on gut microbes to enable them to digets wood or grass. Cattle do ferment food in their stomachs, and they are innoculated in much the same way as termites; the parents lcik the mouths of the young and the rumen micorbes are transferred that way. Other mammals usually ferment food in the intestines, and that requires some far more complex methods of innoculation. Termites have it relatively easy compared to plant eating mammals.
No. The number of organisms that can live in the human stomach can be counted on the fingers of one hand. In fact they can be counted on one finger.
But since these things don’t live much in termite stomachs either that’s not a major issue. Could they live in the human intestine? Sure they could, but in such low numbers you’d never notice any effect beynd flatulence. Humans simply aren’t adapted to that sort of setup. Gorillas are leaf eater, and their inestines are set up to act as micorbial digestors. Most termite flora could live happily in a gorilla gut.
Wood is extemely hard to digest and requires a long time to ferment. As a result you need a massive gut relative to your body size to extract enough energy to survive on wood. A termite body is something like 85% gut by weight. If a human tried that it wouldn’t even allow us to maintain our brain. Even a gorilla couldn’t live on wood and hope to maintain the heart and brain while maintaining the muscles needed to operate the limbs.
Termites get away with eating wood because dragging around a body that consists of little more than stomach is pratical at small sizes, but at large sizes it becomes totally impractical. Added to that termites live slow lives and don’t need much energy. Compare a termite to an ant or cockroach and notice how slowly the termites move in comparison. Their diet provies energy very slowly and they have evolved to use energy very slowly. A mammal simply can not live life that slowly because we need to generate heat.
AFAIK beavers are the only mammals that routinely eat ‘wood’ and even they preferentially eat the sugar rich outer layers of the wood and supplement the diet with higher quality food whenever they can. Even for a beaver true wood is the diet of last resort because it simply doesn’t provide enough energy to survive on.
I need two fingers to count Cryptosporidium muris and Helicobacter pylori, both of which I understand are gastric parasites in humans.
I stand corrected. I hadn’t heard of C. muris. Off to Google.
OK, back from Google. Do you have happen to have a reference that C. muris can live in the human stomach?
Google results seem to suggest that it’s an intracellular infection that is capable of infecting epithelial cells, but nothing suggests it can live in the stomach itself, as opposed to the within the epithelial cells lining the stomach. That’s a very significant difference.
I’m not a parasitologist, but a Google search for “gastric parasite” human turned up several references to C. muris, so I decided to mention it. Some of those references are even careful to distinguish between gastric and intestinal parasites. However, I admit none of them distinguished between parasites living in the stomach and those in its lining.