RETRACTED: Female lizards (Eremias argus) reverse Bergmann's rule across altitude

Abstract

The evolution of body size within and among species is predicted to be influenced by multifarious environmental factors. However, the specific drivers of body size variation have remained difficult to understand because of the wide range of proximate factors that covary with ectotherm body sizes across populations with varying local environmental conditions. Here, we used female Eremias argus lizards collected from different populations across their wide range in China, and constructed linear mixed models to assess how climatic conditions and/or available resources at different altitudes shape the geographical patterns of lizard body size across altitude. Lizard populations showed significant differences in body size across altitudes. Furthermore, we found that climatic and seasonal changes along the altitudinal gradient also explained variations in body size among populations. Specifically, body size decreased with colder and drier environmental conditions at high altitudes, reversing Bergmann's rule. Limited resources at high altitudes, measured by the low vegetative index, may also constrain body size. Therefore, our study demonstrates that multifarious environmental factors could strongly influence the intraspecific variation in organisms' body size.

Age structure and body size of two Tibetan toad (Bufo tibetanus) populations from different elevations in China

“…This rule has been described in many endothermic vertebrates (Birds: Ashton, 2002 ; Olson et al., 2009 ; Mammals: Ballinger & Nachman, 2022 ; Clauss et al., 2013 ; DeVries et al., 2022 ; McQueen et al., 2022 ; Mori et al., 2019 ). However, whether ectothermic vertebrates such as amphibians, which rely primarily on heat from the external environment, follow this rule remains controversial (Deme et al., 2023 ; Khatiwada et al., 2019 ; Yu et al., 2019 ).…”

“…whether ectothermic vertebrates such as amphibians, which rely primarily on heat from the external environment, follow this rule remains controversial (Deme et al, 2023;Khatiwada et al, 2019;Yu et al, 2019).…”