Effects of superparasitism on reproductive fitness of Ooencyrtus fecundus Ferriere & Voegele (Hym. Encyrtidae), egg parasitoid of sunn pest, Eurygaster integriceps Puton (Hem. Scutelleridae)

Ahmadpour, Sajjad; Iranipour, Shahzad; Asgari, Shahryar

doi:10.22059/jbioc.2014.51477

Effects of superparasitism on reproductive fitness of Ooencyrtus fecundus Ferriere & Voegele (Hym. Encyrtidae), egg parasitoid of sunn pest, Eurygaster integriceps Puton (Hem. Scutelleridae)

Document Type : Complete paper

Authors

¹ MSc. Professor, University of Tabriz, Iran

² Associate Professor, Department of Plant Protection, Faculty of Agriculture, University of Tabriz

³ Assistant Professor, Agriculture and Natural Resources Center of Tehran Province, Varamin

10.22059/jbioc.2014.51477

Abstract

Ooencyrtus fecundus Ferriere & Voegele (Hymenoptera: Encyrtidae) is one of the gregarious egg parasitoids of sunn pest that can superparasitize the host. Superparasitism has inverse effects on fitness, reproductive potential, competition ability and adult size of gregarious parasitoids. In this study, the effects of superparasitism and its intensity (four levels including singleton, twin, triplet and quadruplet females) was investigated on biological features of O. fecundus under laboratory conditions. Stable population growth parameters were compared as fitness indicators among four treatments. Significant differences were observed in all parameters except generation time (T). Intrinsic rate of increase (r_m) was estimated to be 0.2529±0.0024, 0.2480±0.0019, 0.2389±0.0023 and 0.2354±0.0019 per day in single, twine triple and quadruple females, respectively. On the other hand, net reproductive rate (R₀) was 198.14±7.22, 188.63±6.72, 170.54±2.04 and 139.77±2.01offsprings and generation time (T) was 20.9±0.29, 21.12±0.18, 21.5±0.21 and 20.98±0.15 days in those treatments, respectively. Although parameters were close to each other, their differences were still significant because their variance was low. In most cases, parameter values were significantly different between singleton and twin females with triplet and quadruplets. Superparasitism affected fitness of individuals, however this effect was not so strong that causes superparasitism remove and it seems that it can also grant considerable advantage to the wasp when host density is scarce.

Keywords