I have been wondering for awile. I seem to get higher yields from my hydei when culturing in plastic as opposed to glass. the media, amount of media and water, number of flies to start and temp are identical. The plastic containers have more rapid growth rates from larva to fly and the larva consume almost all of the media. The glass jars often have media left over as the culture dies out. I can only imagine that the plastic containers might allow for more air exchange and that the slightly drier media does better. Any thoughts?