Mealworms are an excellent feed for all reptiles, birds, and exotic birds. Their nutritional value and taste make them an ideal feed, as they are routinely desired immediately after the first consumption. But, because mealworms are an holometabolic insect, meaning they have a metamorphosis phase, it may be cumbersome to contain the mealworms in their larva stage. If temperatures are too warm, then the worms can transition into the pupa stage, which then transforms into the darkling beetle phase. And if they transform into the darkling beetle phase, they loose their appeal to the reptiles and birds. If the worms the don’t have enough to eat or enough water, then they can easily die in their habitat. So there are a few more obstacles presented with maintaining mealworms in their larva stage.
Keep them refrigerated
The simplest solution is keep them in a refrigerator. The mealworms prefer temperatures around 70 degrees, but you don’t. At 70 degrees, this encourages the mealworms to consume rapidly, which then causes them to transition into the darkling beetle. But, if you can refrigerate them, then that will cause them and their hormones to go dormant, ceasing their metamorphosis. It is the equivalent of cryogenic freezing, without the nitrogen. Basically, keeping mealworms in the refrigerator can increase their larva stage by a couple of months.
There are somethings that the keeper needs to be made aware of regarding the mealworms. Because the mealworms will go dormant, it means that they will go months without eating or drinking any necessary nutrients. So it is crucial that, before refrigeration, the mealworms are given some type of substance that can sustain their bodies during dormancy. Fresh vegetables are the best source to offer them. A fresh cut potato or some fresh carrots will give the worms their needed water and nutrients.
Because the mealworms can last up to a full year before transitioning into the pupa stage, this will give them plenty of time to eat and grow. However, fattening up your mealworms is a delicate balancing act. If you give them too much of what then need to grow, then the can transform sooner than you’d like them too. However, if you deprive them of their nutrients, then they may not grow to the desired size.
So although fattening up your mealworms is a race against the clock, it is still a viable method to grow good-sized mealworms, that can then be refrigerated.