Insects in the feed
Small tasty bites are often used to stimulate the forage behaviour of zoo animals. Apart from that they form an extra variation of diet. Grasshoppers or mealworms are often a part of the daily feed.
The animals can of course also catch the insects already present in their residence, like cockroaches and other pests. The nutritional contribution of these to the diet are hard to estimate. Insects are a good source of proteins and fat, but poor in calcium (Allen, 1989). A calcium deficiency will not easily occur if the offered insects only form a small part of a balanced diet. The total amount of calcium in the diet will not be affected significantly. But this will be the case when animals are fed solely insects. In this case the amount of calcium has to be supplemented to make the calcium-phosphor ratio at least 1:1. This can be done by powdering the insects with chalk. An other option is to feed the insects more than two days on a diet with a calcium level of at least 8%. This method is often used in zoos. Bear in mind though that when the insects are not fed right away, they will excrete the calcium again, which will annul the effect.