This would be evolution/adaptation... If just one cricket is born or adapts in way where it's mating call could both attract females and not (or less cahnce of) attract parasites, it would stand to reason that it would have a greater chance of surviving and mating to pass along these (superior for the situation) traits. In turn, it's offspring who where born with these traits would have a greater chance of survival/reproducing than their siblings and/or other crickets so on an so forth. Fast forward many thousands of years (possibly less for insects due to their rapid life/generation cycles) and this "new" trait will be present in the entire species, which would probably be classified as a different species of cricket.