Would a Daddy Long Legs spider increase in size after eating?

I have recently created a habitat for silverfishes, due to my hate for the things, and as an experiment, unleashed a newly captured Daddy Long Legs spider upon them. To my expectation, the spider realized its roommates and wrapped up one to consume. The next day, the spider seemed to have increased in size around the, I don't know science speak, butt-part. It got pretty big.