01741nas a2200193   4500008004100000245011700041210006900158300001200227490000700239520101400246653001901260653001901279653001901298653002301317653002201340100002401362700002301386856013801409       2006                        eng d00aOffensive and defensive sperm competition roles in the dung beetle Onthophagus taurus (Coleoptera: Scarabaeidea)0 aOffensive and defensive sperm competition roles in the dung beet  a131-1360 v603 aSperm competition is predicted to generate op- posing selection pressures on males. On one hand, selec- tion should favour ‘defensive’ adaptations that protect a male’s ejaculate from displacement, while, on the other hand, selection should favour ‘offensive’ adaptations that overcome paternity assurance mechanisms of rivals. Here, we use the sterile male technique to assess sperm pre- cedence when a male dung beetle Onthophagus taurus mates in both a defensive (first male) and an offensive (second male) role. Significant variation in a male’s sperm precedence (both P1 and P2) was detected, and an individual’s defensive (P1) and offensive (P2) abilities were positively correlated. Thus, it appears that sexual selection simultaneously selects for ‘defensive’ and ‘of- fensive’ adaptations in O. taurus. We discuss a variety of male traits in O. taurus that potentially contribute to a male’s ability to be successful whenmatinginan‘of-fensive’ and a ‘defensive’ role. 10aDefensive role10amale genitalia10aOffensive role10aOnthophagus taurus10aSperm competition1 aHouse, Clarissa, M.1 aSimmons, Leigh, W.  uhttps://scarabnet.myspecies.info/offensive-and-defensive-sperm-competition-roles-dung-beetle-onthophagus-taurus-coleoptera-scarabaeid