As in many other hymenopterans, sex in Habrobracon hebetor (Say) (Hymenoptera: Braconidae) is determined by single-locus complementary sex determination. Thus, unfertilized eggs become haploid males and fertilized eggs that are homozygous and heterozygous at the sex locus develop into diploid males and females, respectively. We investigated the effect of temperature during development on the production and survivorship of diploid males. Females were allowed to oviposit at 20[degree]C and 27[degree]C and progeny remained at the same temperature throughout development. Diploid males were produced at both temperature regimes indicating that temperature does not affect sex determination in H. hebetor. However, temperature did affect diploid male survivorship, which was higher at the low temperature. Plodia interpunctella (Pyralidae) : Host Habrobracon hebetor (Braconidae) : Parasite Reproduction; Genetics; Cytogenetics; Chromosomes; Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts; Ecology; Population dynamics; Abiotic factors; Physical factors Habrobracon hebetor; Sex determination; Karyotype; Diploid males; Lepidopteran hosts; Diploid male production; survival & sex determination; temperature effects; Plodia interpunctella; Survival; Temperature Plodia interpunctella; Hymenopteran parasites; Parasite diploid male production; survival & sex determination; temperature effects; Habrobracon hebetor; Temperature none