Differential sex allocationin sand lizards: brightmales induce daughterproduction in a specieswith heteromorphic sexchromosomes
2005
Olsson, M | Wapstra, E | Uller, T
In sand lizards (Lacerta agilis), males withmore and brighter nuptial coloration also havemore DNA fragments visualized in restrictionfragment length polymorphism analysis of theirmajor histocompatibility complex class I loci(and, hence, are probably more heterozygous atthese loci). Such males produce more viableoffspring, with a particularly strong viabilityeffect on daughters. This suggests that femalesshould adjust both their reproductive investmentand offspring sex ratio in relation to malecoloration (i.e. differential allocation). Ourresults show that experimental manipulation ofpartner coloration in the wild results in signifi-cantly higher maternal effort and a 10% higherproportion of daughters than sons. This supportsthe hypothesis that females increase theirmaternal energetic expenditure and adjust theiroffspring sex ratio in response to high-qualitypartners. However, it also suggests that this hasprobably evolved through natural selection forincreased offspring viability (primarily throughproduction of daughters), rather than throughincreased mate attraction (e.g. sexy sons).
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