LIFE HISTORIES AND SEASONAL BIOLOGY OF FOUR HYPERPARASITES OF THE TOBACCO HORNWORM, MANDUCA SEXTA (LEPIDOPTERA: SPHINGIDAE)

Abstract

AbstractHypopteromalus tabacum (Fitch), Catolaccus aeneoviridis (Girault), Spilochalcis side (Walker), and Spilochalcis hirtifemora (Ashmead) were hyperparasites of the tobacco hornworm, Manduca sexta (Linnaeus), most frequently reared from cocoons of the primary parasite, Apanteles congregatus (Say). The life history of each species was studied and the distinctive features of egg, last larval instar, and pupal stage were described.In 1969 through 1972 parasitization of the tobacco hornworm by A. congregatus started at low levels in June or July, increasing to nearly 100% by the end of September. A corresponding increase in the seasonal incidence of hyperparasitism was observed, although the level of hyperparasitism never exceeded 85% in any year. Each year S. side and S. hirtifemora were the first hyperparasites recorded; however, H. tabacum was always the most abundant. The number of C. aeneoviridis varied greatly from year to year.Peak spring emergence of H. tabacum and C. aeneoviridis occurred in April just before that of the primary parasite, A. congregatus, and as this was several months prior to their appearance in tobacco fields a number of possible alternate hosts for the hyperparasites were investigated.