Age-specific functional response of wolbachia-infected strain of the parasitoid, Trichogramma brassicae at different densities of Ephestia kuehniella

One of important aspects in evaluating the efficiency of a natural enemy is the attack rate across a range of host densities, i.e., its functional response. In this research, age-specific functional response of wolbachia-infected strain of parasitoid, Trichogramma brassicae to different egg densities (5, 10, 20, 30, 40, 60 and 80) of Ephestia kuehniella at 23 ± 1° C, 60 ± 5% RH and 16:8 h (L:D) photoperiod was evaluated. The type III functional response was obtained for one and two day old wasps, and a type II for 3 to 9 day old ones. Searching efficiency (a), handling time (Th) and maximum parasitism rate (T/Th) of parasitoid wasps were significantly affected by their ages. With increasing in parasitoid age a non-significant declining trend was shown in searching efficiency (a) but handling time (Th) increased significantly as adult parasitoid aged and the lowest value was observed at 1st day of parasitoid’s life (0.573 h). Also, by increasing in parasitoid age maximum parasitism rate (T/Th) clearly declined and it ranged from 41.75 to 5.51 hosts at 1st up to 9th days of wasp life. The results illustrated that age-specific functional response of T. brassicae wasps were different and the highest efficiency gained in the first two days of their life.