BIOLOGICAL STUDIES ON MONORTHOCHAETA-NIGRA BLOOD-AND-KRYGER (HYM, TRICHOGRAMMATIDAE) AS EGG PARASITOID ON THE TORTOISE BEETLE, CASSIDA-VITTATA VILL (COL, CHRYSOMELIDAE)

Laboratory experiments were carried out to study the relationship betw een the egg parasitoid, Monorthochaeta nigra, and its host, Cassida vi ttata. The results indicated that the number of eggs deposited per fem ale and the percentage of parasitism decreased as host egg density inc reased. When the parasitoids were reared under laboratory conditions, the results obtained indicated that increasing temperature (from 20 to 25 then to 30 degrees C) had a negative effect on the oviposition per iod, post-oviposition period: adult longevity for males and females, t he number of deposited eggs, the percentage of parasitism and the numb er of emerged parasitoids or successful parasitism. However, the longe st oviposition period (4.4 +/- 0.9 days), post-oviposition period (5.8 +/- 1.5 days), and longevity (9.2 +/- 0.9 and 10.0 +/- 1.9 days for m ales and females, respectively), the highest number of deposited eggs (76.0 +/- 14.1 egg/female), and the highest number of emerged parasito ids or the successful parasitism (67.6 +/- 11.1/female or 89%) were re corded for parasitoids reared under the lowest tested temperature (20 degrees C).