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Directional changes in sexual size dimorphism in shorebirds, gulls and alcids
Author(s) -
Lindenfors P.,
Székely T.,
Reynolds J. D.
Publication year - 2003
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1046/j.1420-9101.2003.00595.x
Subject(s) - sexual dimorphism , monomorphism , biology , polygyny , sexual selection , mating system , fecundity , zoology , natural selection , evolutionary biology , mating , ecology , selection (genetic algorithm) , demography , population , mathematics , injective function , artificial intelligence , sociology , computer science , pure mathematics
The Charadrii (shorebirds, gulls and alcids) are one of the most diverse avian groups from the point of view of sexual size dimorphism, exhibiting extremes in both male‐biased and female‐biased dimorphism, as well as monomorphism. In this study we use phylogenetic comparative analyses to investigate how size dimorphism has changed over evolutionary time, distinguishing between changes that have occurred in females and in males. Independent contrasts analyses show that both body mass and wing length have been more variable in males than in females. Directional analyses show that male‐biased dimorphism has increased after inferred transitions towards more polygynous mating systems. There have been analogous increases in female‐biased dimorphism after transitions towards more socially polyandrous mating systems. Changes in dimorphism in both directions are attributable to male body size changing more than female body size. We suggest that this might be because females are under stronger natural selection constraints related to fecundity. Taken together, our results suggest that the observed variation in dimorphism of Charadrii can be best explained by male body size responding more sensitively to variable sexual selection than female body size.