Geographical morpho-physiological variability is linked to genetic diversity in an intertidal false limpet

Intertidal rocky shores have spatial and temporal heterogeneity in their environmental conditions that make them suitable systems in which to explore variations in species' morpho-physiological and genetic traits. The effect of air desiccation on the mortality and rates of water loss (W-L) of Siphonaria lessonii was tested during prolonged air exposure (48 h) at different temperatures (8 and 18 degrees C) and its relation to shell shape in contrasting geographic habitats. Morphometric and genetic data (ISSR-PCR technique) in limpets from contrasting geographic habitats were thus compared, considering humid temperate climate (MDQ, 38 degrees of latitude) and semi-arid climate (SAO 40 degrees of latitude). These field samplings were complemented with laboratory experiments on W-L and mortality under different temperatures. All samples were collected during September and October 2010 from both sites. Both W-L and mortality were dependent on size and the habitats where specimens were collected. Specimens collected from SAO (semi-arid climate) were also found to be less sensitive to air exposure at moderate temperatures (e.g., 18 degrees C) and prolonged air exposure (48 h) compared to MDQ. These patterns agree with morphotype variation in shell size and genetic constitutions between sites. These data demonstrate that the sensitivity of this species to air exposure can change with environmental conditions (such as temperature) and may be dependent on habitat. This shows a previously unknown geographic differential capacity of this limpet to modify W-L in response to changes in temperature, which may have further implications on species and genetic distribution in the context of climate change.