Androgenesis in Hordeum vulgare L. : physiological and molecular aspects / Sietske HoekstraThe value of haplotypes / Anne René de VriesThe value of haplotypes / Anne René de VriesGenetic basis of sex determination in the haplodiploid wasp 'Nasonia vitripennis' / Eveline Catharina VerhulstGenetic basis of sex determination in the haplodiploid wasp 'Nasonia vitripennis' / Eveline Catharina VerhulstDeadly combinations : hybrid incompatibilities in the parasitic wasp genus Nasonia / Tosca Ferber-KoevoetsDeadly combinations : hybrid incompatibilities in the parasitic wasp genus Nasonia / Tosca Ferber-KoevoetsSexual selection and sex allocation / Abraham Leendert Willem KuijperSexual selection and sex allocation / Abraham Leendert Willem Kuijper