Comparative biological aspects of two strains from the egg parasitoid, Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae) in Egypt

Two geographical strains from the egg parasitoid, Trichogramma evanescens Westwood (TE) were derived from parasitized egg-masses of the lesser sugar-cane borer, Chilo agamemnon Bles., collected from sugar Cane fields at Komombo (Aswan Governorate - Upper Egypt) (UET) and From rice fields at Sakha (Kafr EL-Shiekh Governorate Lower Egypt; (Delta)) (LET). The study was carried Out to check wheather the two Strains are Subspecies, geographical eco-types or two species through estimating their thermal requirements, cross-mating test and DNA analysis, developmental periods, rate of parasitism, emergence rates and sex ratio of both UET and LET using, the grain moth, Sitotroga cerealella Oliv. eggs as host were obviously influenced by different temperatures. Developmental thresholds (t), for the period pupa to adult (stage 2) (8.3 and 10.7 degrees C) for the two strains were relatively higher than the (t) for the period. egg to adult (stage 3) (7.1 and 6.4 degrees C) and much higher than the period, egg to pupa (stage 1) (2.8 and 1.2 degrees C), respectively. Recorded values were higher For UET than for LET at stages 1 & 3, while it was vice versa in stage 2. The heat sum requirement for the development (k) of UET was 31.6 day-degree higher than that for LET. Random Amplified Polymorphic DNA polymerase Chain Reaction (RAPD-PCR) and cross-mating) tests proved that the strains belong to the same species, T. evanescens.