Mosquitoes are more attracted to people already infected with malaria
It looks like malaria somehow makes its host more delicious to mosquitoes, via tdj
Mosquitoes are more attracted to people already infected with malaria. And this appears to be because the malarial parasite orchestrates its own onward transmission from within the human body, a new study suggests.
...
“What’s surprising is that this is not to the advantage of anybody but the parasite,”...“This tremendously important interaction for the person and the mosquito - both can die as a result - is being engineered by the parasite.”
This "engineering" is natural selection: parasites who implement the mechanism multiply more.
But it seems really unlikely that you could orchestrate both sides of the deal via random mutations... so one of them must have been accidentally tuned to start with (before this mechanism evolved): either (1) the different human smell became a side-effect of the parasite while the effect on the mosquito's attraction to that smell has always been the same; or (2) the other way around (effect on human smell always been the same, effect on mosquito behavior evolved). The first seems more likely, especially since the evidence says nothing about the parasite influencing mosquito behavior.
I would bet that, if for some reason mosquitos stop being attracted to that smell, there is nothing the parasite can do about it. (the alternative would be that the parasite could quickly adapt to make infected mosquitos attracted to that smell again, but my claim here is there would have to be a big fluke for them to hit upon such a mechanism (since mutation is random), unless a similar thing were already encoded in the parasites' genes)
Mosquitoes are more attracted to people already infected with malaria. And this appears to be because the malarial parasite orchestrates its own onward transmission from within the human body, a new study suggests.
...
“What’s surprising is that this is not to the advantage of anybody but the parasite,”...“This tremendously important interaction for the person and the mosquito - both can die as a result - is being engineered by the parasite.”
This "engineering" is natural selection: parasites who implement the mechanism multiply more.
But it seems really unlikely that you could orchestrate both sides of the deal via random mutations... so one of them must have been accidentally tuned to start with (before this mechanism evolved): either (1) the different human smell became a side-effect of the parasite while the effect on the mosquito's attraction to that smell has always been the same; or (2) the other way around (effect on human smell always been the same, effect on mosquito behavior evolved). The first seems more likely, especially since the evidence says nothing about the parasite influencing mosquito behavior.
I would bet that, if for some reason mosquitos stop being attracted to that smell, there is nothing the parasite can do about it. (the alternative would be that the parasite could quickly adapt to make infected mosquitos attracted to that smell again, but my claim here is there would have to be a big fluke for them to hit upon such a mechanism (since mutation is random), unless a similar thing were already encoded in the parasites' genes)