Yeah, I have at least nine mosquito bites on my right foot and ankle, apparently courtsy of a mosquito that got in while I was repairing the screen door (or possibly immediately before I repaired it), and the itching has been driving me nuts all night. When it comes to ecosystems and species, in the words of the Lord High Executioner¹,
I've got a little list,
They'd none of them be missed ...
...and mosquitoes are DEFINITELY on my list of species I Wouldn't Miss from our ecosystem. The only useful function they serve is as fish food, and other species would take up that slack.
[1] As in Gilbert & Sullivan's The Mikado, naturally.