Table 1 Non-social hymenopteran species for which sl-CSD has been proposed to be the sex determining mechanism. Confidence codes indicate the levels of evidence: 1 = post hoc explanations for exceptionally high male biased sex ratios in cultures or field surveys, 2 = on the basis of the verification of male diploidy through cytological (chromosome number), morphological (size, weight, density of wing microchaetae), genetical (microsatellites) or electrophoretical (allozymes) methods, 3 = on the basis of the sex ratios in inbreeding experiments in accordance with predictions under CSD, 4 = the joint combination of level 2 and 3, and 5 = linkage mapping of the sex locus and/or its molecular characterization

From: Single locus complementary sex determination in Hymenoptera: an "unintelligent" design?