It only repels 50% of the bites though. Thus, those that bite, will survive and make babies. Some of them will be able to bite, others not. Eventually, only th

It only repels 50% of the bites though. Thus, those that bite, will survive and make babies. Some of them will be able to bite, others not. Eventually, only those that can bite will survive. I don't see how it can go the other way. Where eventually since only half of them bite, that ratio declines to zero. Can that happen with evolution? I suppose there is a tipping point where if enough of the population can't find each other then they all die alone. Like rats in Alberta.