Or is it that the victims pest warning system is currently winning the biological arms race, in which case how are mosquitoes able to successfully reproduce? Or is it that mosquitoes have evolved such that their spawning numbers offset the difficulty they have biting?
Biology is hard.
Evolution doesn’t work that way. They don’t evolve X because of Y. They develop essentially random mutations, and the ones that make them fitter for survival get passed on to their offspring. They don’t get to decide that they don’t want you to itch and then evolve that ability.
It’s a common rhetorical shortcut to anthropomorphize evolution. Doing so doesn’t necessarily indicate that the writer doesn’t understand how evolution works. It’s just cumbersome to repeat an explanation of random mutation and natural selection in every discussion of evolved trait.
Neither creatures nor evolution get to “decide” to develop a trait but, as countless evolutionary arms races show, useful traits and refinements do tend to happen in a way that evokes a sense of conscious decision making.
I meant as the ones that have mutations that cause them to itch get whacked, the remaining ones that dont get to pass on this trait to their offspring,creating a generation of itchless bugs, not that this mosquito one day decides to evolve a non itching bite because he thinks it might benefit his bloodline.
The itch doesn’t begin until well after the female mosquito gets her food and leaves, so what reproductive advantage does it give to that specific mosquito over the others to make the itch not happen at all? The answer is “none”.