Annddd just realized I already replied to this and the forum decided not to load said reply. Now here we are in the infinite expanse of space.I use homemade fruit fly culture media to give the adult flies some nutrients and water. Is that considered gut loading? I don't know which nutrients mantids (or invertebrates in general) need, but this seems to keep them plump and juicy a little longer. The media contains sugar, brewer's yeast, and potato flakes.