Experimental evidence for pseudo-arrhenotoky in Hypothenemus hampei (Coleoptera: Scolytidae)

Abstract

Species breeding under local mate competition conditions have sex ratios biased towards females, a trait that is often associated with male haploidy (arrhenotoky). We used insecticide resistance as a genetic marker in Hypothenemus hampei, a local mate competing scolytid beetle that is cytologically diplo-diploid, for investigating the inheritance of nuclear genes. We confirmed that males express the resistance phenotype that they inherit from their mother, whatever their father. The segregation of resistance phenotypes in F2 females significantly departed from the Mendelian model, and were in accordance with the arrhenotokous model, indicating that the parental genes were eliminated between F1 and F2. This finding (pseudo-arrhenotoky) constitutes a step towards an understanding of the mechanism by which diplodiploidy evolves to arrhenotoky in local mate competing insects. ©1996 The Genetical Society of Great Britain.