why do butterflies lay false eggs? The reason I ask is because I found 3 eggs on my hop vine, but they were all empty...but unhatched at the same time. why would a butterfly waste energy laying eggs with no embryo? it just seems pointless to me!
They don't know any better. just like all the chicken eggs at the grocery store aren't fertilized. They can't tell the difference.
Put it under some major magnification and I'm guessing you will see where some insect/spider poked a hole in the shell and had a meal. I've caught insects having a monarch milkshake.