Urbanization and the common wall lizard (Podarcis muralis) in the Pannonian basin, Serbia: nowhere safe?

Abstract

Numerous studies of urban environment impact on wildlife imply urbanization can have both negative and positive effects. Phenotypic variation of pileus in the common wall lizard (Podarcis muralis) was analysed to determine whether urbanization levels can be associated with developmental instability induced by environmental stress. Pileus developmental pathways and instability in natural, suburban and urban populations were quantified by patterns of size and shape, fluctuating asymmetry (FA), modular organization and integration, allometric trajectories and frequency of phenodeviants. Our results show high asymmetry and modular structure of pileus with the high frequency of phenodeviants for natural, suburban and urban populations indicating elevated developmental instability in all three habitat types. However, some peculiarities were observed comparing habitats – the lowest level of FA and integration in urban populations and unexpectedly high level of FA and frequency of phenodeviants in the natural population. In addition, significant correlations between symmetric and asymmetric shape patterns, and presence of modular organization for all three habitat types suggest that genetic/environmental and developmental parcellation are somewhat aligned. Our results indicate that pileus morphology varies in a complex manner and future studies that link physiological, behavioural and morphological parameters to demographic parameters and fitness are necessary to fully understand how environmental stress affects developmental instability.