I know this thread is very old, but it's one of the only really relevant links to come up when you google this. After never finding a satisfactory answer, I just tried it in my indoor plastic tote worm bin (made from 2 nested 10 gallon totes from Lowes http://www.lowes.com/pd_332449-61896-332449_1z0yly3__?productId=3276019&pl=1), and the worms adore sourdough starter. At first I thought something was wrong because every worm in the bin ended up in a giant, writhing mass where the starter was put down, but it turns out they were just super excited to eat it.

It gets kind of hot, though, so be careful with quantity if the temp where you keep your worms is high. You'll see more condensation in the bin with the starter in there. I've put down up to 1/4 cup with no bad consequences to my bin. I don't know about larger quantities--I would guess it depends on the size of your bin and worm population.

I had no problems with odor generally, but there can be a funk for a
while if you uncover just the area where the starter is--probably
because it can cause a wet, sludgy spot. I've since started to take out some older bedding and mix it into the starter before putting it down. The worms seem to prefer to eat the castings/organic matter/bedding that has soaked up the starter rather than eat the starter itself anyway, and it helps me control moisture better. If I notice that the spot with the starter is getting compacted and funky, I fluff it, and it seems to nip the problem in the bud.

Anyway, I'm sure this is no help to the original poster anymore, but maybe this will help the next person who Googles for the answer to whether it's OK to feed sourdough starter to the worm bin.