Thanks-I didn't get them indoors as I take out at least once a day. the compost has a tight fitting lid but the stupid little door thing at the bottom has gaps-I guess that is what happened. they seem a bit whiter than fruit flies but I wasn't really looking!

I can't put a layer of soil over each day really as it will get very time consuming and awkward...well I will if I have to but it will be tedious!

Any other ideas?