Maternal nest-site choice in response to saline substrates differs between island and inland populations of lizards

Abstract Nest-site choice influences offspring development and varies in response to specific environmental cues. For species that inhabit coastal regions, salinity of the nest site is probably an important factor for nesting females, whereas this cue is likely to be rare or absent for inland populations. We compared nest-site choice of brown anole lizards (Anolis sagrei) between an island population (that frequently experiences seawater inundation) and an inland population (that rarely, if ever, experiences inundation). We hypothesized that island females would avoid nesting in saline soils more than inland females, because it impairs egg hatching success. We provided females from each population with two different nesting substrates (soil mixed with freshwater vs. saltwater). We incubated their eggs in these conditions to quantify the effects on embryo survival. Island females tended to avoid nesting in saltwater soil, whereas inland females exhibited no preference. Water loss and mortality rates of eggs increased during incubation in soil with saltwater. These patterns imply that females from island populations, but not inland populations, might have adaptive behavioural responses to soil salinity. These results have important implications for understanding how coastal or island populations might respond to changes in salinity under climate change (e.g. sea level rise, increased hurricanes).