Distribution of fluctuating asymmetry in skull shape of Capromys pilorides (Mammalia: Rodentia) across Cuban archipelago

Abstract

The fluctuating asymmetry (AF) is a pattern of random deviations from perfect bilateral symmetry, that can be used as a measure of developmental instability and could be an indicator of environmental stress. In species with wide distribution range, populations could be experimenting different environmental and/or genetic levels of stress, and several studies have observed increasing AF in peripheral areas and/or marginal habitats (e.g. low suitability). The Conga hutia, Capromys pilorides, is the most widely distributed native rodent of Cuba and exploits a broad variety of habitats, resulting in a large degree of variation in environmental conditions. In this study, we combined geometric morphometric and ecological niche modelling (ENM) analyses to examine whether the AF levels of skull in ventral view of populations of C. pilorides are associated with environmental suitability. According to the ENM, C. pilorides is predicted to occur across most Cuban archipelago; however, coastal strip, small cays and highland regions had highest values of environ mental suitability. Only small areas associated to central plains of main island show unsuitable habitats. We found higher AF in populations that inhabit on small cays compared to Cuba and Isla de la Juventud. Contrary to the expected, we found a significant positive relationship between environmental suitability and AF levels. However, the ENM of C. pilorides is strongly biased by the current distribution, more frequent on small mangrove cays and coastal localities of hard access, due to local extinctions of many populations in side main island of Cuba linked to historical overhunting, predation by dogs and deforestation. Despite of their highest values of environmental suitability, cays could represent sub-optimal habitats to C. pilorides. Compared to the habitats on main island and Isla de la Juventud, on cays this species depends almost exclusively on mangrove as food and water resource. Furthermore, the geographic isolation of these populations could to reduce genetic variability or heterozygosity increasing the AF levels.