Table 1.
Sexual System | Mating System | Spawning mode | Sperm competition | GSI | Prediction |
---|---|---|---|---|---|
PG | Harem polygyny | Pair | Low | Low | Low |
Lek polygyny | Pair | Low | Low | ||
Promiscuous large groups* | Group | High | High | ||
PA | Monogamy | Pair | Low | Low | Low |
Random pair mating | Pair | Low | Low | ||
Promiscuous small groups | Small group | Low | Low | ||
Promiscuous large groups** | Group | High | High | ||
G | Promiscuous large groups | Group | High | High | High |
Monogamy (size assortative mating) | Pair | Low | Low | ||
Monogamy (random pair mating) | Pair | Low | Low |
The prediction column summarizes the overall expectation on sperm competition (and thus GSI) for the sexual system, based on the most common mating and spawning mode, according to the SAM23,24.
*Protogynous group spawners should be favoured as large males can produce more sperm28.
**Promiscuous large groups are not common, but still present in protandrous species (see text for examples).