Often, too many insects develop in your Hive Explorer because the mealworms were obtained at the same life stage. Simply put, this is sometimes not avoidable.
Two things you can try to do in this case are to either a) Put the insect of the prior life stage in the refrigerator to slow down their development (eg: If you have too many beetles, put the pupae in the fridge, if you have too many pupae, put the mealworms in the fridge) or b) Harvest your insects, feed them to your pets or compost them.