Natasha, mine didn't really llike the earthworms first up either - but I persisted and now around 5 of my 8 axies will eat them. Have you tried prawn flesh, bits of fish, frozen krill or other frozen food?
I'm going to add a comment here and I'll probably get flamed but - I have fed beef liver almost exclusively to my original male and female - they are perfectly healthy, lay eggs, look good, all that stuff. Since being on these forums however, I have cut that back a lot and now feed earthworms, small bits of fish, prawns and also still heart and liver, but less of it. Quetzal is eight, Tonantzin is around 5(?). No adverse effects yet.