REPRODUCTIVE-BIOLOGY OF BIOSTERES-ARISANUS (SONAN), AN EGG LARVAL PARASITOID OF THE ORIENTAL FRUIT-FLY

Biosteres arisanus (Sonan) is an internal egg-larval parasitoid candid ate for biological control programs directed against several fruit fly pests of the family Tephritidae. To facilitate development of mass pr oduction methods, basic biological data pertaining to the reproductive activity of B. arisanus were collected. Daily progeny production for the cohort-age interval 6-20 days was found to be optimum, and a disca rd age of 21 days is recommended. The overall mean progeny production per day (50.4 +/- 4.2 parasitoids) was doubled to 105.4 +/- 23.2 when parasitoids were increased from 50 to 100 females/cage. In parasitoid cages of 200 females, mean progeny production per day peaked at 297.1 +/- 43.8 parasitoids at age interval 6-10 days. Mean progeny yield/cag e was 1309, 2433, and 3401 parasitoids when the initial cohort density was 50, 100, and 200 females, respectively. An oviposition exposure p eriod of 6 h was optimum to minimize rates of host mortality or superp arasitism. Unparasitized host puparia of Bactrocera dorsalis (Hendel) from parasitoid exposure cages can be efficiently separated by the siz e of host puparia. Up to 99.5% of the total B. arisanus emerged from p upal size class 1 (maximum width = 1.7 mm, maximum length = 4.1 mm) to size class 4 (maximum width = 2.1 mm, maximum length = 4.9 mm). Most of the unparasitized adult flies (80.6%) emerged from pupal sizes larg er than size class 4. Furthermore, 97.6% of B. arisanus that emerged f rom size class 1 were males. Percentages of male parasitoid progeny de clined significantly as the host puparial size increased (almost-equal -to 3% females emerged from class 4 and 5 puparia). (C) 1994 Academic Press, Inc.