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Sexual size dimorphism in the T yrrhenian tree frog: a life‐history perspective
Author(s) -
Cadeddu G.,
Giacoma C.,
Castellano S.
Publication year - 2012
Publication title -
journal of zoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.915
H-Index - 96
eISSN - 1469-7998
pISSN - 0952-8369
DOI - 10.1111/j.1469-7998.2011.00878.x
Subject(s) - sexual dimorphism , biology , fecundity , sexual selection , mating , zoology , selection (genetic algorithm) , reproductive success , perspective (graphical) , demography , ecology , evolutionary biology , population , artificial intelligence , sociology , computer science
Sexual size dimorphism ( SSD ) is often explained as the differential equilibrium between stabilizing survival selection and directional sexual/fecundity selection on the body size of males and females. Provided that survival selection is similar in both sexes, female‐biased SSD is thought to occur when fecundity selection on female body size is stronger than sexual selection on male body size. However, in animals with indeterminate growth, body size depends on several life‐history traits, thus, to understand why SSD has evolved, one should understand how it arises. We investigate SSD in the T yrrhenian tree frog, H yla sarda , by describing sexual dimorphism in age and growth and by assessing how body size affects their reproductive success. Females are 16% larger than males because they mature 1 year later, live 1 year longer and reach a larger asymptotic body size. Furthermore, body size correlates positively with female fecundity, but not with male mating success. These results suggest that SSD arises from differential optimal trade‐offs between the expected number of reproductive episodes (which decreases with prolonging growth) and the expected success in each reproductive episode (which increases with prolonging growth).