Spatial patterns in the size of Chinese lizards are driven by multiple factors

Abstract

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Living in difficult situations: Lizards living in high altitudes have smaller body sizes due to extreme climatic conditions and limited resources

“…Expressly, our results found evidence for the influence of both resource availability and seasonality (i.e., precipitation seasonality) on female body size, with smaller body sizes associated with decreased seasonality and lower primary productivity. Previous studies have suggested that highly seasonal changes in rainfall significantly influence the abundance of available resources for female lizards (Valenzuela-Sanchez et al, 2015;Meiri et al, 2020;Slavenko et al, 2021), which is positively related to large body sizes (Liang et al, 2021). Perhaps this is not surprising since unpredictable seasonal changes at high altitudes may suggest scarce resources for lizards (Deme et al, 2022a;Anderson et al, 2022).…”

“…In contrast studies have shown some ectotherms follow Bergmann's rule, possessing large body sizes at high latitudes (e.g., Angilletta et al, 2004). The original explanation for Bergman's rule did not account for the peculiarity of ectotherms (Watt et al, 2010) in their inability to generate significant internal body heat, and consequently that a larger bodied ectotherm would therefore heat up more slowly (Stevenson, 1985) and would lack the ability to conserve heat in colder environments (Liang et al, 2021). Further, possessing larger bodies in colder environments may be deleterious to some ectotherm species (Jadin et al, 2019;Velasco et al, 2020;Slavenko et al, 2021); since ectotherms with large body sizes that slowly heat up in colder environments show constrained thermoregulatory behavior (Pincheira-Donoso et al, 2008;Anderson et al, 2022;Szymkowiak and Schmidt, 2022).…”

“…Plastic and evolutionary responses to altitudinal clines may influence inter-and intraspecific variation in body size among ectotherms (Lu et al, 2018a;Meiri, 2018;Norris et al, 2021;Giovanna et al, 2022), due to the often rapid changes in annual and seasonal variation in temperature and precipitation across altitude (Liang et al, 2021;Anderson et al, 2022). For instance, studies have suggested that ectotherm body sizes may increase at low elevations with optimal seasonal environments (seasonal environments that allow ectotherms to have more active time) (Slavenko et al, 2019), likely because optimal seasonal environments allow for increased time available for ectotherms to acquire resources (Horváthová et al, 2013).…”

“…China, has a rich diversity of over 212 species of lizards belonging to 10 families (Zhao et al, 1999;Zhou et al, 2019;Wang et al, 2020). However, how body size varies with geographic and climatic clines has only recently been explored for this region, especially when considering body size variation across populations (see, Guo, 2016;Liang et al, 2021). For example, female lizards inhabiting colder environments at higher gradients within China (from tropical to temperate regions) were found to possess small body sizes as adaptive plasticity for reproductive ecology (Lu et al, 2018a;Deme et al, 2022b), suggesting that the body sizes of the female lizards may as well follow climatic clines for adaptation to environmental (climatic) conditions (Feldman and Meiri, 2014;Brusch et al, 2022).…”

“…Eremias argus lizard populations occupying high altitudes across China may experience unique local climatic conditions and unpredictable seasonal changes (Deme et al, 2022a), which may be different for other lizards globally, because of regional differences in climatic conditions (see, Sinervo et al, 2010;Meiri et al, 2013;Meiri, 2018). As studies have suggested that lizard populations across China that occupy unfavourable environments, which may reduce lizards' body size (Liang et al, 2021;Wang et al, 2021), we set out to ask (i) whether E. argus follow a reverse Bergmann's cline across altitudes to physiologically adapt to local environmental changes? (ii) if variation in resource availability, climate, and seasonality across altitudes will explain the patterns of lizards' body sizes.…”