Abstract
Sperm competition is predicted to generate opposing selection pressures on males. On one hand, selection 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 precedence 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 P 1 and P 2) was detected, and an individual's defensive (P 1) and offensive (P 2) abilities were positively correlated. Thus, it appears that sexual selection simultaneously selects for 'defensive' and 'offensive' 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 when mating in an 'offensive' and a 'defensive' role.
| Original language | English |
|---|---|
| Pages (from-to) | 131-136 |
| Number of pages | 6 |
| Journal | Behavioural Ecology and Sociobiology |
| Volume | 60 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - Jun 2006 |
| Externally published | Yes |
Keywords
- Defensive role
- Male genitalia
- Offensive role
- Onthophagus taurus
- Sperm competition