FACULTATIVE EGG-LARVAL PARASITISM OF THE BEET ARMYWORM, SPODOPTERA-EXIGUA (LEPIDOPTERA, NOCTUIDAE) BY COTESIA-MARGINIVENTRIS (HYMENOPTERA, BRACONIDAE)

The braconid parasitoid Cotesia marginiventris (Cresson) has long been known to be a larval parasitoid of numerous lepidopteran species. Rec ent field observations, however, indicated that C. marginiventris is a lso capable of functioning as an egg-larval parasitoid of the beet arm yworm, Spodoptera exigua (Hubner). These field observations mere corro borated by laboratory observations, demonstrating that C. marginiventr is is capable of ovipositing in S. exigua eggs, and of successfully de veloping and emerging from host larvae hatching from stung eggs. The m echanisms used by the parasitoids to locate host egg masses in the fie ld were not determined. These results lend support to phylogenetic hyp otheses of the Braconidae that indicate a close relationship between t he Cheloninae and the microgastroid taxa.