My Tarantula got a little fat before her moult. She had a three inch legspan and before going on a fast for a month had been eating three or four adult black crickets a week. She got a big bum. Now, her abdomen is roughly the same size as it was before the moult, except now it's smaller compared to the rest of her body. She has a robust body but her abdomen looks like it shrunk considerably. When she starts eating again, she's going on a bit of a diet this time.