Influence of diet on biology and life-table parameters of the predacious mite Euseius scutalis (A.H.) (Acari: Phytoseiidae)

Abstract

Studies on the developmental duration, immature survival, longevity, reproduction, and life-table parameters of the predatory mite, Euseius scutalis Athias-Henriot were carried out under laboratory conditions of 28 ± 1°C and 75 ± 5% relative humidity (RH). The food sources for the predator included Ricinus communis pollen, eggs and nymphs of Eutetranychus orientalis, moving stages of Aceria ficus and Rhyncaphytoptus ficifoliae and immature stages of Icerya aegyptica. Development was faster and reproduction was higher when E. scutalis fed on R. communis pollen, while the developmental time increased and reproduction decreased when fed on R. ficifoliae. The number of A. ficus consumed was significantly higher compared with R. ficifoliae. Life-table parameters showed that a diet of R. communis pollen provided the shortest generation time (T = 9.51511 days), female longevity (21.37 days), the highest intrinsic rate of natural increase (rm = 0.33789) and greatest total fecundity, which resulted in the high net reproductive rate (Ro = 24.906) value. Aceria ficus and R. ficifoliae showed a relatively close value of (T = 11.59057 and 11.5222), (rm = 0.218029 and 0.2158297), (λ = 1.243623 and 1.240891) and the number of eggs deposited per female per day (1.20 and 1.20 eggs/♀/day). Eggs of E. orientalis were the least favourable source of food among all food tested.