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Ontogenic sources of variation in sexual size dimorphism in a viviparous lizard
Author(s) -
LE GALLIARD J.F.,
MASSOT M.,
LANDYS M. M.,
MEYLAN S.,
CLOBERT J.
Publication year - 2006
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 - 10.1111/j.1420-9101.2006.01094.x
Subject(s) - sexual dimorphism , biology , juvenile , offspring , lizard , ontogeny , zoology , maternal effect , ecology , population , sexual selection , pregnancy , demography , endocrinology , genetics , sociology
To elucidate the developmental aspects of the evolution of sexual size dimorphism (SSD), an understanding of the sex‐specific ontogeny of body size is critical. Here, we evaluate the relative importance of genetic and environmental determinants of SSD in juvenile common lizards ( Lacerta vivipara ). We examined the prenatal and post‐natal effects of population density and habitat humidity on SSD, as well as the maternal effects of food availability, corticosterone level, humidity and heat regime during gestation. Analyses indicated strong prenatal and post‐natal plasticity in body size per se and yielded three main results with respect to SSD. First, SSD in juvenile common lizards matches qualitatively the SSD observed in adults. Secondly, SSD was influenced by none of the prenatal factors investigated here, suggesting poor sex‐biased maternal effects on offspring size. Thirdly, SSD was sensitive to post‐natal habitat humidity, which positively affected growth rate more strongly in females than in males. Thus, natural variation in SSD in juvenile common lizards appears to be primarily determined by a combination of sex‐biased genetic factors and post‐natal conditions. We discuss the possibility that viviparity may constrain the evolution of sex‐biased maternal effects on offspring size.