Fitness de Amblyseius largoensis (MUMA) e Euseius concordis (Chant) (Acari: Phytoseiidae) sob diferentes condições alimentares e preferência por ovos de diferentes idades de Aleurodicus cocois (Curtis) (Hemiptera: aleyrodidae)

Abstract

Predatory mites Amblyseius largoensis and Euseius concordis have been suggested as potential biological control agents of the cashew whitefly, Aleurodicus cocois. These predators occur naturally in cashew leaves independent of the occurrence of A. cocois, so they could contribute to pest control by feeding on their eggs and consequently hampering their establishment. However, biology studies of these predators demonstrated that A. cocois eggs may even support the development of predators but present poor reproductive quality. Thus, the present study was conducted with both species of predators and delineated to evaluate: (i) the quality of A. cocois eggs in relation to other food items (T. urticae and castor pollen); (ii) whether the combination of different food items (A. cocois + castor pollen or T. urticae + castor bean pollen) could represent an increase in the fitness of predators (increased daily oviposition); (iii) whether the presence of castor bean pollen could affect the consumption of A. cocois eggs; (iv) the fitness (consumption and oviposition) of predators against new (up to 24hrs) and old (> 48hrs) eggs of A. cocois; and (v) the food preference of predators against new and old eggs of A. cocois. The results showed that for both predators the exclusive pollen diet provides a higher rate of daily oviposition, suggesting a higher nutritional quality. The increase of pollen to the egg-based diet of A. cocois only represents an increase in the fitness of E. concordis. The presence of pollen did not affect the consumption of A. cocois eggs by predators, however the predation by A. largoensis was higher than that observed for E. concordis. In tests with no chance of choice both predators consumed more old eggs than new eggs of A. cocois, the conversion of this predation into egg biomass was similar for both predators. In experiments with chance of choice both predators consumed a larger number of old eggs than new eggs of A. cocois.