Radiolabeling Heliothis virescens1 Eggs by 32P Injection of Adult Females2

Abstract

A technique is described for radiolabeling Heliothis (F.) eggs by injecting adult females with a pulse dose of ³²P. An expected DPM/egg can be predicted from various doses by the following equations: log Ħ = —4.99 + 1.19 (log X), log Ŷ = —5.67 + 1.27 (log X) and log Ŷ = —5.55 + 1.25 (log X) for 72, 96, and 120 h, respectively. The pupal weight of H. virescens was unrelated to the amount of label incorporated into eggs subsequently laid by the adults. Larvae of the predator, Chrysopa carnea (Stephens), did not distinguish between normal and ³²P labeled eggs of the same age.