Foliage from greenhouse-grown soybeans fumigated with 524 εgm−3of SO2or from control plants held under the same conditions without fumigation was fed to Mexican bean beetle larvae and adults. The larvae developed faster and grew larger when fed on the fumigated leaves; larval mortality was consistently low and showed no apparent relationship to the type of leaves used as the food source. Adult females showed a significant feeding preference for discs cut from fumigated leaves and were more fecund when fed on the treated foliage than when fed on control leaves. A greater percentage of the females laid eggs, and the viability of the eggs was higher when the females were fed on fumigated leaves. These females produced more eggs per individual, with significant increases in both the number of eggs per mass and the number of masses per female. The longevity of egg-laying females did not differ significantly between the treatments.