Article Dans Une Revue The American Naturalist Année : 2024

Strength of Sexual Selection and Sex Roles Vary between Social Groups in a Coral Reef Cardinalfish

Résumé

The strength and direction of sexual selection can vary among populations. However, spatial variability is rarely explored at the level of the social group. Here we investigate sexual selection and sex roles in the paternally mouthbrooding, socially monogamous, and site-attached pajama cardinalfish, Sphaeramia nematoptera. Females were larger and more aggressive and had a longer dorsal fin filament, indicating reversed sex roles. At the scale of social groups, we show that the Bateman gradient and reproductive variance depend on the sex ratio and size of groups. In small andmedium-sized groups with balanced or male-biased sex ratios, Bateman gradients were steeper for females, whereas gradientswere equally steep for both sexes in large groups orwhen the sex ratio was female biased. For both sexes, reproductive variance increased with group size and with a higher male-to-female sex ratio. In S. nematoptera,mating opportunities outside the socially monogamous pair appear to impact sexual selection. We conclude that strength and direction of sexual selection can be masked by social dynamics in group-living species when considering

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Dates et versions

hal-04903880 , version 1 (21-01-2025)

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Theresa Rueger, Chancey Macdonald, Hugo Harrison, Naomi Gardiner, Geoffrey Jones, et al.. Strength of Sexual Selection and Sex Roles Vary between Social Groups in a Coral Reef Cardinalfish. The American Naturalist, 2024, 204 (3), pp.289-303. ⟨10.1086/731422⟩. ⟨hal-04903880⟩
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