All of a sudden these little flies have appeared, 13 in one blunder trap! is this seasonal? or do they like to eat certain things? (there is no food or food waste anywhere near them though). We can't find where they are coming from, we don't have any EAT ME pellets on the traps, so it's coincodence they ended up there. Any ideas would be greatly appreciated! Also I'm just calling them 'little flies' - do they have a proper name?