none Bracon hebetor females were exposed to 3 ppm SO sub(2) for 3h and 5h and their reproductive performance was assayed for 20 days. Lifespan of the treated females and their egg production were not different from those of control wasps. Also, egg hatchability, an important indicator of fertility, was not consistently affected. These results indicate Bracon) reproductive performance, a sensitive toxicological assay system, is resistant to acute SO sub(2) exposure. Putative SO sub(2) effects on parasitic wasp populations in nature are therefore probably not due to interference with female fecundity and fertility.