Seyed Moravvej, Hossein Lotfalizadeh, Parviz Shishehbor,
Volume 4, Issue 1 (3-2018)
Abstract
This contribution reports 15 species of Encyrtidae (Hymenoptera: Chalcidoidea) belonging to 12 genera from Khuzestan province of Iran of which 11 species were determined to species level. Five genera and seven species are new for the fauna of Khuzestan province. Three genera viz. Apoleptomastix, Rhopus and Thomsonisca, and three species viz. Apoleptomastix bicoloricornis (Girault, 1915), Leptomastidea bifasciata (Mayr, 1876) and Rhopus nigroclavatus (Ashmead, 1902) are new for the Iranian fauna.
Volume 9, Issue 3 (5-2020)
Abstract
Ooencyrtus fecundus Ferriere and Voegele (Hymenoptera: Encyrtidae) is a gregarious egg parasitoid of sunn pest Eurygaster integriceps Puton. Superparasitism enables a female to produce multiple progeny per host and thus reduces the time spent searching for hosts, but results in progressively smaller progeny as more individuals compete for limited resources within hosts. In this study, we tested whether gregarious development would affect the functional response of O. fecundus reared under laboratory condition (26 ± 2 ºC, 50 ± 10% RH and 16: 8 L: D h). Various host densities (1, 2, 4, 8, 16 and 32 eggs) were offered to females that had developed either as single, or as twins, triplets or quadruplets within host eggs. To resolve the functional responses of these females, a total exposure time of five hours was chosen, based on direct observations of handling time and the maximum daily number of host attacks/female. Functional response of the parasitoid was type III in singleton and twin parents, and type II in triplet and quadruplet ones. However, host mortality rate was 100% in host densities ≤ 8, suggesting density independence at lower densities as expected from a type I functional response. In such circumstances, handling time is expected to be zero, but was observed to be 11.4 to 14.3 minutes in different treatments. These results suggest that when enough time was available to find and handle all hosts, a type II functional response resembles Type I one. Searching efficiency increased and handling time decreased with body size of the parasitoid of four categories.
