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

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 ( approximately 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.