I mostly work on flour beetles (Tribolium castaneum). In order to do research on flour beetles I have to make sure that I always have enough beetles to work with.
It just happens to be that this beetle is a pest species! So they are very easy to breed.
We keep the beetles in ordinary bread boxes with holes in the lid, this box is party filled with flour in which yeast is mixed. The beetles dig around in the flour and eat both yeast and flour. The yeast is rich in proteins which gives them that little bit of extra protein they need to develop extra quickly. Below a picture of one of those bread boxes we keep the colony in.There are a lot of beetles in one box, so removing the beetles one by one is no option. To separate the beetles, larva, pupae or eggs from the flour we use sieves. We use one sieve which doesn’t allow beetles to pass through but does allow eggs to pass and 1 sieve that doesn’t allow eggs to move through but the flour does. And of course a bin to catch the flour.So first we sieve the beetles from the flour:Then we sieve the eggs from the flour:The eggs are to small too see them clearly without the microscope. But all the white dots you see in the sieve are eggs, so that are a lot of eggs! We put these eggs into a new box with flour and yeast, after 3.5 days at 30 degrees Celcius the eggs hatch and these larvae will start eating. After about a month at 30 degrees they are fully grown, pupated and hatched as adult beetles. Below the eggs with a human hair as a size reference, second picture from left to right: larva, pupa and adult.