Comparison of biological characteristics of the predatory mite Blattisocius mali (Acari: Blattisocidae) reared on frozen eggs of Tyrophagus putrescentiae (Acari: Acaridae) alone and in combination with cattail and olive pollens

Abstract

Blattisocius mali (Oudemans), known as a predator of some species of storage pest mites, was reared on frozen eggs of Tyrophagus putrescentiae (Schrank) alone (Tp) but also supplemented with cattail (Tp + cattail) and olive (Tp + olive) pollen. Life table parameters of B. mali were evaluated in the first (G1), eighth (G8) and sixteenth (G16) generation on the three different diets. Survival of the immatures of the predator was not affected by the tested diets, whereas it significantly differed among generations. The highest and lowest mortality was observed in the G8 and G1 generations, respectively, on all diets. Except for the total pre-oviposition period (TPOP) and the adult pre-oviposition period (APOP), all life table parameters of B. mali were affected by the different diets; In G1, supplementation of (Tp) with both pollens significantly increased the fecundity, oviposition period and female life span of B. mali. Population growth parameters of the predator like intrinsic rate of increase (r), net reproductive rate (R0) and finite rate of increase (λ) significantly increased with the supplementation of (Tp) with cattail pollen. However, in G8 and G16, B. mali reared on the two combinations significantly showed the lowest values of oviposition period, female and male life span and mean generation time (T) (only F8). Except for female and male developmental times and TPOP, other biological parameters of B. mali significantly differ across generations. Adding both pollens to the frozen eggs of the prey mite, significantly decreased fecundity, oviposition period, female and male life span and population parameters such as (r), (T), (λ) of B. mali in G16 compared with G1. With comparison of the effects of diet through the generations on biological and population parameters of B. mali, it is concluded that frozen eggs of T. putrescentiae is strongly advisable for mass-rearing of the predator and mixed frozen diets (containing pollen) is suggested as supplemental diet for establishment of the predator after release.