SINGLE-LOCUS AND MULTILOCUS DNA-FINGERPRINTING OF COMMUNALLY BREEDINGPUKEKO - DO COPULATIONS OR DOMINANCE ENSURE REPRODUCTIVE SUCCESS

In behavioral and ecological studies the ''function'' of dominance hie rarchies is thought to be related to reproductive success. In particul ar, dominant males are regarded as likely to gain a reproductive advan tage due to enhanced ''access'' to females. We compare the dominance s tatus of adults with the frequency of copulations and the patterns of parentage in communally breeding pukeko or purple swamphen (Porphyrio porphyrio melanotus). This avian species has an unusual social system, often breeding in polygynandrous groups in which there is a strong do minance hierarchy. Typically, during the breeding season, there is con siderable sexual activity, with heterosexual and homosexual copulation s between adults being commonplace. Hae III-digested DNA from individu als belonging to breeding groups was hybridized to the minisatellite D NA probe YNH24, revealing putative single-locus profiles, while hybrid ization of the same DNA to the minisatellite probes pV47-2, 3'HVR, and per revealed typical multilocus profiles. The numbers of unattributab le restriction fragments allowed the maternity and paternity of all in dividuals to be conclusively determined, despite high levels of band s haring among individuals within breeding groups. These close genetic s imilarities are a likely consequence of strong philopatry and inbreedi ng. We report instances of males which are high on the dominance hiera rchy but have only a limited reproductive output in comparison with ot hers and males which are subordinate but achieve a significant proport ion of fertilizations. Generally these data reveal no consistent relat ionship between dominance, the frequency of copulations, and parentage among males. We conclude that pukeko highlight some difficulties with conventional explanations for the ''function'' of dominance.