You are ascribing a utility optimisation to evolution that doesn't happen. There is an arms race happening on the selection because those who successfully procr

You are ascribing a utility optimisation to evolution that doesn't happen. There is an arms race happening on the selection because those who successfully procreate proliferate, and it can be difficult to undo changes. It doesn't matter if it's wasted energy or complications to have egg level defense mechanisms, if this trait evolved once because for whatever reason that selectivness was increasing chances of passing down those genes, absent négative sélection pressure and a viable genetic pathway out it's gonna stay there. If there's a evo geneticist around, one thing I'm wondering is whether some of these traits might have evolved as a heck from the male side. E.g., if I have mutations that increase selectivness of the females against everyone but me, passing those mutations would bias later generations to select for my gene line. I'm not sure whether this is feasible or likely, but it's an example of evolutionary benefit without any real benefit if possible