10.6084/m9.figshare.9249413.v1
Fabrizia Ronco
Fabrizia
Ronco
Marius Roesti
Marius
Roesti
Walter Salzburger
Walter
Salzburger
Supplementary Information from A functional trade-off between trophic adaptation and parental care predicts sexual dimorphism in cichlid fish
The Royal Society
2019
Lake Tanganyika
mouthbrooding
trophic morphology
gill rakers
2019-08-05 07:00:19
Journal contribution
https://rs.figshare.com/articles/journal_contribution/Supplementary_Information_from_A_functional_trade-off_between_trophic_adaptation_and_parental_care_predicts_sexual_dimorphism_in_cichlid_fish/9249413
Although sexual dimorphism is widespread in nature, its evolutionary causes often remain elusive. Here, we report a case where a sex-specific conflicting functional demand related to parental care but not to sexual selection explains sexual dimorphism in a primarily trophic structure, the gill rakers of cichlid fishes. More specifically, we examined gill raker length in a representative set of cichlid fish species from Lake Tanganyika featuring three different parental care strategies: (i) uni-parental mouthbrooding, whereby only one parental sex incubates the eggs in the buccal cavity; (ii) bi-parental mouthbrooding, whereby both parents participate in mouthbrooding; and (iii) nest guarding without any mouthbrooding involved. As predicted from these different parental care strategies, we find sexual dimorphism in gill raker length to be present only in uni-parental mouthbrooders, but neither in bi-parental mouthbrooders nor in nest guarders. Moreover, variation in the extent of sexual dimorphism among uni-parental mouthbrooders appears to be related to trophic ecology. Overall, we present a so far unrecognized scenario for the evolution of sexual dimorphism that is not related to sexual selection or initial niche divergence between sexes. Instead, sexual dimorphism in gill raker length in uni-parental mouthbrooding cichlid fish appears to be the consequence of a sex-specific functional trade-off between a trophic function present in both sexes, and a reproductive function present only in the brooding sex.