Hi all. Mosquitoes and bed bugs that dint give us an itch after being bitten would have had an enormous advantage over normal mosquitoes and bed bugs as we wouldnt notice or bother if we dint feel anything. By natural selection, these types of bugs would have had an edge over current bugs. I've come to know that the itching sensation is due to the compounds the bugs inject to prevent blood clot while they suck. So, why dont we have irritation-less mosquitoes and bed bugs? Is it because there isnt a compound that both doesnt irritate us and prevents blood clot or hasn't there been enough time for them to evolve?