Adaptive social and maternal induction of antipredator dorsal patterns in a lizard with alternative social strategies


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Maternal effects facilitate adaptation to changing environments because they alter individual offspring traits to match current conditions. We show that maternal effects can also resolve context-dependent, correlational selection on multiple offspring traits, promoting adaptation to more complex environments. In side-blotched lizards (Uta stansburiana), two alternative pathways of dorsal pattern induction involve maternal oestradiol and alleles for throat colouration (∼social strategy). In one pathway, females increased yolk oestradiol when mated to yellow-throated sires; oestradiol induced dorsal barring in yellow-throated progeny of both sexes. In another pathway, females elevated yolk oestradiol in response to a high frequency of orange alleles in experimental social neighbourhoods. When the sire lacked yellow alleles, this secondary pathway resulted in striped, orange sons and striped, non-orange daughters. All maternally induced types had high fitness in the wild. These results illustrate a (previously undescribed) mechanism for females to simultaneously resolve differing correlational selection pressures on different progeny.