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VIVIPARITY AS A CONSTRAINT ON SEX‐RATIO EVOLUTION
Author(s) -
Uller Tobias
Publication year - 2003
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.0014-3820.2003.tb00303.x
Subject(s) - sex ratio , biology , offspring , sex allocation , life history theory , evolution of sexual reproduction , life history , reproductive success , zoology , evolutionary biology , demography , ecology , pregnancy , genetics , gene , population , sociology
In polytocous mammals, the sex ratio during gestation can influence a variety of morphological, physiological, and life‐history traits because of steroid leakage between fetuses. Similar phenomena have also recently been described for a viviparous lizard. Some of these effects have important fitness consequences by influencing reproductive success later in life. Thus, biasing the sex ratio toward one sex may lead to a decreased fitness for the other sex, and therefore constrain the evolution of skewed sex ratios. By incorporating effects of sex ratio on offspring fitness in a simple sex‐allocation model, I show that, under some circumstances (1) skewed sex ratios are predicted to evolve, and (2) this cost can constrain the evolution of skewed sex ratios.