Abstract
Ecogeographical rules help explain spatial and temporal patterns in intraspecific body size. However, many of these rules, when applied to ectothermic organisms such as reptiles, are controversial and require further investigation. To explore factors that influence body size in reptiles, we performed a heuristic study to examine body size variation in an Australian lizard, Boulenger's Skink Morethia boulengeri from agricultural landscapes in southern New South Wales, south-eastern Australia. We collected tissue and morphological data on 337 adult lizards across a broad elevation and climate gradient. We used a model-selection procedure to determine if environmental or ecological variables best explained body size variation. We explored the relationship between morphology and phylogenetic structure before modeling candidate variables from four broad domains: (1) geography (latitude, longitude and elevation), (2) climate (temperature and rainfall), (3) habitat (vegetation type, number of logs and ground cover attributes), and (4) management (land use and grazing history). Broad phylogenetic structure was evident, but on a scale larger than our study area. Lizards were sexually dimorphic, whereby females had longer snout-vent length than males, providing support for the fecundity selection hypothesis. Body size variation in M. boulengeri was correlated with temperature and rainfall, a pattern consistent with larger individuals occupying cooler and more productive parts of the landscape. Climate change forecasts, which predict warmer temperature and increased aridity, may result in reduced lizard biomass and decoupling of trophic interactions with potential implications for community organization and ecosystem function.
Highlights
Spatial and temporal variation in intraspecific body size is driven by differences in the heritability of phenotypic traits, and is the basis of evolution and adaptation to environmental change [1,2,3]
2.1 Phylogenetic structure We identified 29 mitochondrial ND2 gene haplotypes among the M. boulengeri sampled
We examined factors affecting body size variation in a widespread Australian lizard on a regional-scale
Summary
Spatial and temporal variation in intraspecific body size is driven by differences in the heritability of phenotypic traits, and is the basis of evolution and adaptation to environmental change [1,2,3]. Bergmann’s rule states that races (or as Bergmann probably intended, closely related species, especially congenerics) of warm-blooded vertebrates from cooler climates tend to be larger than races occupying warmer climates [8]. This rule, which is independent of gender, was originally reserved to explain interspecific differences in body size, modern interpretations often extend the rule to include intraspecific investigations. Studies show a converse Bergmann cline or no obvious relationship between body size and latitude [14,15,22,23,24,25]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
