Search for: All records

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). 

Abstract Theory predicts that thermal developmental plasticity evolves in response to thermal heterogeneity, suggesting that plasticity may be an important trait for establishment in novel climates. However, few studies use multispecies comparisons to examine how plasticity evolves, meaning that there is little empirical basis with which to examine key theoretical predictions. We estimate patterns of thermal developmental plasticity in morphological and performance traits for 7 Anolis lizard species inhabiting South Florida, USA. We found interspecific differences as well as intraspecific variation in reaction norms across species. Neither temperature heterogeneity in present-day invasive ranges in Florida nor historical temperature heterogeneity from the contemporary native ranges predicted reaction norm variation. Phylogeny and species identity typically predicted around 90%–95% of reaction norm variation. Overall, these results suggest that thermal developmental plasticity in these traits exhibits variation that could be inconsistent with patterns expected under adaptive evolution to macroclimate. Examining the role of maternal nesting behavior and sampling of additional species can help to distinguish between neutral variation and selection toward multiple adaptive peaks. Our comparative study of thermal developmental plasticity in lizards provides new insights about macroevolutionary dynamics behind the evolution of developmental plasticity and the conditions under which adaptive plasticity is expected to evolve.