Earlier quoted context omitted.
100 flies = 1 mouse. However, mosquitos have absolutely no value and can be exterminated to extinction. We could even make it a holiday.
Everything in the ecosystem has value, that’s why it exists. Many creatures eat mosquitos and ants and the like. They also help to spread disease that keeps the population of the species they, in turn, prey on in check.
And "being useless" doesn't mean mosquitoes don't have a place in the ecosystem. Everything does. What it means is that other species don't rely mosquitoes exclusively. For example, birds that feed on mosquitoes can also eat other insects, and these insects are likely to become more prolific to fill the void created by the destruction of mosquitoes.
In fact, the objections to eradicating mosquitoes are usually along the lines of:
- It is morally wrong. It is not a scientific argument but it is not without merit.
- The mosquito is really good at preventing humans from doing bad things. For example by making tropical rain forests inhospitable, or even by controlling human population through diseases.
I have an issue with the second argument. Saying that something is good because it makes the lives of some people miserable. It sounds a bit like an argument of the kind "it is a good thing that people are dying from malaria right now, it will make the world a better place for my children".
So for me, there is no scientific argument against eradicating mosquitoes, though I can be wrong. It is more about the moral argument about the importance of nature vs our well-being. In many cases, preserving nature is good for our long term well-being, but it appears not to be the case when it comes to mosquitoes.