 Consistent with the arms race theory, DNA analyses reveal a two-fold increase in Acp divergence relative to non-reproductive proteins 

For many females, reproduction can be very dangerous and disadvantageous as in the case of bed bugs mentioned previously.Therefore, females who possess traits where they can lessen the impacts of male behavior are the ones who will survive and go on to reproduce.There are many ways a female can "defend" herself to the onslaught of potential mates.