Is it true that unfertilized females will only lay sterile eggs that won't hatch?

Question

The females that never mated, do they lay eggs that won't hatch (with no baby inside)? Does it apply to all insects, birds, reptiles and other egg laying animals?

Answer 1

Sometimes a female will lay an egg without mating with a male and will produce a healthy offspring. This is called parthenogenesis and is fairly rare for most species. Most recently a komodo dragon was touted as doing this. It's actually a fairly common method of reproduction for some species of Xiphophora fish and for some species of geckos. Female bees produce males without benefit of mating but need a mate (as far as we know) to produce females.

Answer 2

All animals MUST be fertilized to produce offspring, with a few exceptions.  There is a species of lizard that is only females, and they can lay eggs that do hatch.

I believe there are also some lower forms of insects, like water fleas, that can do this.

But, Crickets, no, they must mate first to produce viable eggs.