opportunity for polymorphism and genic variation in social hymenoptera with worker-produced males

• Published in: Heredity 1985-01, Vol.54 (1), p.25-36
• Main Author: Owen, R.E
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Animals; Autoecology; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Cytogenetics; Ecology; Evolutionary Biology; Fundamental and applied biological sciences. Psychology; genetic variation; Genetics of eukaryotes. Biological and molecular evolution; Human Genetics; Hymenoptera; original-article; Plant Genetics and Genomics; polymorphism; Population genetics, reproduction patterns; Protozoa. Invertebrata
• ISSN: 0018-067X; 1365-2540
• DOI: 10.1038/hdy.1985.5

In many eusocial Hymenoptera, for example, bumble bees, a proportion, ψ of the males are produced by the workers. The conditions for there to be at least one stable polymorphic equilibrium were found to be, w 11 v 1 – ½ψv 2 (w 11 – w l2 ) < ½w 12 (v 1 + v 1 ) > w 22 v 2 – ½ψv 1 (w 22 – w 12 ); where w 11 , w 12 w 22 are respectively the fitnesses of the female genotypes A 1 A 1 , A 1 A 2 , A 2 A 2 and v 1 , v 2 are the fitnesses of the male genotypes A 1 and A 2 . The equilibrium gene frequencies are given by the root(s) of a cubic polynomial. The conditions given above were shown to be both sufficient and necessary to find all stable equilibria for three regular selection models analysed in detail: (1) Codominance and (2) Dominance with opposite selection in the sexes (3) Overdominance with identical selection in the sexes. The effect of worker-produced males on the probability of a polymorphism and the expected genic variation was investigated for these three models. Compared to other Hymenoptera, species with worker-produced males will have a reduced frequency of polymorphisms and lower mean genic diversity at loci with dominant and overdominant fitnesses. In contrast at loci with codominant fitnesses the probability of a polymorphism and the genic diversity will be higher if the selective differentials are large (0–1·0), with smaller selective differentials (0–0·125, 0–0·01) a reduction will again occur. Therefore the overall level of genic diversity depends on the proportion of codominant loci and the selection intensity.