Think of it this way. In nature there are animals and bugs that fit every niche of life. In the case your having there are bugs that will feed on the waste of higher level animals. This is nature’s way of cleaning up and also enhancing the soil for future plant growth. So if you have a healthy balance of different bugs in your enclosure then you have a very well balanced vivarium and that is a very good thing. In nature there is just a vast array of living creatures that make up the biosphere where we live. It's only when things get out of balance that things take a turn for the worse. Examples are being overrun with insects, or algae blooms in lakes...ect. Given time nature will restore the balance and things return to normal. If you’re really concerned about it then try and identify what you have seen and go from there.