Artificial Rearing of Entomophagous Insects, with Emphasis on Nutrition and Parasitoids - General Outlines from Personal Experience

The disposability of high numbers of entomophagous insects for their use in biological control strategies is an old objective carried on, between others, by the rearing in different kinds of artificial diets. The definition and the perfecting of these diets are at first based on nutritional studies. Food or carcass analyses, nutritional balance studies, and deletion/supplementation methods allow to evaluate the different nutritional needs. Nitrogen sources are the most critical needs especially with fast growing entomophagous insects. Lipids and carbohydrates mainly constitute energy sources with storage possibility. Other nutrients such as salts and vitamins are also needed, and sometimes some specific polyunsaturated fatty acids. There are other important physiological requirements, concerning the digestion process, the respiration, or the hormonal balances. Physico-chemical factors such as Osmotic Pressure and pH often show critical values for the normal development, mostly of endoparasitoid insects. For egg parasitoids and predators, the presentation of the food is of prime importance for a normal food intake, and finally for the success of the rearing. Sterilization of the diet or incorporation of preservative agents is often necessary for preventing bacterial or fungal contaminations. Many successes were obtained for artificial rearing of entomophagous insects, but ultimate efforts are still needed for crucial improvements and supports that may lead to the extension of the use of this biological control strategy.