SEX DETERMINATION IN THE HYMENOPTERAN DIADROMUS-PULCHELLUS (ICHNEUMONIDAE) - VALIDATION OF THE ONE-LOCUS MULTI-ALLELE MODEL

Males of the hymenopteran Diadromus pulchellus are normally haploid, b ut diploid males can be obtained by inbreeding. Inbred crosses within strains that are polymorphic at the enzymatic loci Pgm-2 and Ao-4 or t hat differ by a body colour mutation produce heterozygous diploid male s in offspring. The genotypic distributions observed in such progeny w ere compared with expected results under the one-locus sex determinati on model or the two independent loci model. The results show that only the one-locus multi-allele model fits the data and allow a provisiona l estimate of approximately 15 sex alleles. These conclusions generali ze the case of existence of a single locus to determine sex in Hymenop tera and are discussed at the evolutionary level.