Comparison of artificial diets for rearing Bracon hebetor Say (Hymenoptera: Braconidae)

The ectoparasitoid Bracon hebetor Say is an insect frequently found in storage facilities, where it attacks stored grain pests. The biology of this parasitoid was studied when reared on seven different artificial diets (in vitro rearing), under controlled temperature (25 +/- 2 degreesC), relative humidity (60 +/- 10%), and photoperiod (14-h photophase), and compared to its biology on its natural host Anagasta kuehniella (Zeller) (in vivo rearing). The artificial diet contained 60% holotissue of Diatraea saccharalis (Fabricius) pupae, 12% fetal bovine serum, 12% lactoalbumin hydrolysate, and 16% egg yolk, enabled development similar to that obtained on the natural host. The life cycle duration (egg-adult) was not significantly different, and the adults reared on this diet promptly paralyzed and parasitized the natural host, though at a lower proportion than those reared in vivo. There was no difference in the longevity of females obtained with these two different rearing systems (in vivo and in vitro). However, about 60% of the larvae developed on the diet failed to produce a protective cocoon during the pupal phase, indicating a sub-optimal quality associated with this artificial medium. (C) 2003 Elsevier Inc. All rights reserved.