Natural diets versus factitious prey: comparative effects on development, fecundity and life table of Amblyseius swirskii (Acari: Phytoseiidae)

Using the most suitable alternative diets that are easily available and less expensive than the natural diets may give rise to reduce the rearing costs of natural enemies. Alternative or additional food used for this purpose should be in accordance with the food spectrum of the respective mite species. To our knowledge no information is accessible on the comparison between natural diets and factitious prey for Amblyseius swirskii Athias-Henriot. Therefore, the objective of this study was to evaluate the nutritional value of three natural diets including almond pollen, maize pollen and Tetranychus urticae Koch, as well as four factitious prey comprising eggs of Ephestia kuehniella Zeller, Tyrophagus putrescentiae (Schrank), decapsulated and encapsulated cysts of Artemia franciscana Leach for A. swirskii. The data would seem to suggest that developmental time of individuals fed on pollens was shorter than that of those fed on factitious prey. The gross and net reproductive rate, intrinsic and finite rate of increase of the individuals consumed factitious prey were lower than those of mites fed on natural food diets, for the simple reason of shorter developmental time and higher oviposition rate of this predator on the latter. In conclusion, our results showed that natural foods were more favorable than factitious prey and among them almond pollen and maize pollen were the most suitable for A. swirskii, and thus it should be taken into account for application in its mass production, and supporting its population in greenhouse or field conditions when used in an augmentative approach.