4 ms·

Semantics point/question: The T. gondii, as viewed from the cat's perspective might be a symbiote, but from the rat's perspective, is certainly a parasite, isn

by liber8 15y ago

Semantics point/question: The T. gondii, as viewed from the cat's perspective might be a symbiote, but from the rat's perspective, is certainly a parasite, isn't it? The T. gondii is benefiting at the expense of the rat. Do biologists classify things as both simbiotes and parasites?

gojomo 15y ago
I think some rats also benefit: their adventurousness and increased sexual activity isn't always penalized with death, and even when it is, female rats prefer the infected male rats. So even if they live fast and die young, they may leave more offspring. Whether this is a net benefit at any one time probably depends on lots of things, and especially relative rat/predator populations. Just as human reproductive preferences seem to change in relation to wealth, population density, and life-expectancy. Regarding semantics, I do think something can be both a symbiote and parasite. When I first learned of 'symbiosis' it was in the context of mutually-beneficial relationships, but it seems the term can be more general. Wikipedia says scientists sometimes disagree whether 'symbiosis' should only be used to describe 'mutualist' relationships (where both benefit) or also 'parasitic' (one benefits and other is harmed) and 'commensal' (one benefits and other neither harmed nor helped) relationships. I should have used the word 'mutualist' in my above post, as that's what I was intending to imply. But the conjecture is intentionally fuzzy about whether the benefit is to the individual (it perhaps sometimes is) or the species (it perhaps always is, as long as both infection and non-infection are well-distributed).
- AutoCorrect 15y ago
  think of it as an agent of accelerated evolution
masklinn 15y ago
> Do biologists classify things as both simbiotes and parasites? I don't know about that, but I know ichneumonid and braconid wasps have built exactly that relation with viruses: http://en.wikipedia.org/wiki/Polydnavirus http://en.wikipedia.org/wiki/Polydnavirus

by liber8 15y ago

gojomo 15y ago

I think some rats also benefit: their adventurousness and increased sexual activity isn't always penalized with death, and even when it is, female rats prefer the infected male rats. So even if they live fast and die young, they may leave more offspring. Whether this is a net benefit at any one time probably depends on lots of things, and especially relative rat/predator populations. Just as human reproductive preferences seem to change in relation to wealth, population density, and life-expectancy. Regarding semantics, I do think something can be both a symbiote and parasite. When I first learned of 'symbiosis' it was in the context of mutually-beneficial relationships, but it seems the term can be more general. Wikipedia says scientists sometimes disagree whether 'symbiosis' should only be used to describe 'mutualist' relationships (where both benefit) or also 'parasitic' (one benefits and other is harmed) and 'commensal' (one benefits and other neither harmed nor helped) relationships. I should have used the word 'mutualist' in my above post, as that's what I was intending to imply. But the conjecture is intentionally fuzzy about whether the benefit is to the individual (it perhaps sometimes is) or the species (it perhaps always is, as long as both infection and non-infection are well-distributed).

AutoCorrect 15y ago
think of it as an agent of accelerated evolution

masklinn 15y ago

> Do biologists classify things as both simbiotes and parasites? I don't know about that, but I know ichneumonid and braconid wasps have built exactly that relation with viruses: http://en.wikipedia.org/wiki/Polydnavirus http://en.wikipedia.org/wiki/Polydnavirus