For some reason whenever I picture you guys I always imagine uber nerds. Hair in a bowl cut, glasses, pocket protectors, pants pulled up too high. I guess you guys are really just nature nuts like me, and Acorn though.
My first guess would definitely be that a hidden insect ate it. Hard to imagine a mantis eating an ooth, but I never pictured them eating turkey either, so who knows. Is there anyway it could have somehow fallen behind something?
It probably hasn't been done. If you really feel like breeding them you'll have to dedicate more time to finding them. Then I guess just see how they interact with each other.