The influence of operational sex ratio on reproductive success in male sheepshead minnow (Cyprinodon variegatus)

What is it about?

Operational sex ratio is predicted to determine the strength and direction of sexual selection. Here, pupfish, a promiscuous species with male alternative mating strategies, were observed under female-biased (8F:4M), male-biased (8M:4F), or equal sex ratio (6F:6M) conditions. Microsatellites were used to determine paternity of eggs. The most aggressive male in each group monopolized the most spawning substrate and sired the most eggs, but contrary to our predictions, mating success was unaffected by operational sex ratio.

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