Tarantulas are primarily nocturnal. Most of my Ts ( and everyone elses) don't care,they will eat day or night.. I only have a few finicky individuals.this is something i never even considered, that they might be night hunters, I mean my P. metallica is always out when im asleep, im kind of dumb for not at least thinking about this, I will test it out for science. unless someone knows already.
But yea maybe yours prefers to feed after dark.. Give it a shot..