Phenotypic responses to incubation conditions in ecologically distinct populations of a lacertid lizard: a tale of two phylogeographic lineages

Abstract

AbstractWe experimentally studied the effects of genetic legacy (eastern vs. western phylogeographic lineage) and population of origin (lowland vs. highland) on the sensitivity of lizard embryos and juveniles to incubation temperature and moisture among four populations of the lacertid Psammodromus algirus. Incubation time was longer at lower temperature, increased slightly at higher moisture, and shorter for highland than for lowland females. Eggs incubated at 24°C produced larger, heavier and shorter tailed hatchlings than those incubated at 32°C. Western juveniles survived better during their first month of life than eastern ones, and juveniles incubated at 32°C survived better than those incubated at 24°C; survivorship was lowest for 24°C hatchlings from the eastern, lowland population. Because juveniles incubated at 32°C grew more rapidly, after 1 month they had compensated their initial size disadvantage. Juveniles incubated at 80% moisture were larger and/or heavier than those incubated at 10% moisture both at hatching and after 1 month. Our results show that although incubation temperature was the main source of phenotypic variation, not all its effects were evident at hatching. Because western juveniles were more tolerant to incubation at low temperature than eastern ones, we suggest that such differences may have limited the westward expansion of the eastern lineage.