Geographic variation in body size and its relationship with environmental gradients in the Oriental Garden Lizard, Calotes versicolor

Abstract

Patterns of geographic variation in body size are predicted to evolve as adaptations to local environmental gradients. However, many of these clinal patterns in body size, such as Bergmann's rule, are controversial and require further investigation into ectotherms such as reptiles on a regional scale. To examine the environmental variables (temperature, precipitation, topography and primary productivity) that shaped patterns of geographic variation in body size in the reptile Calotes versicolor, we sampled 180 adult specimens (91 males and 89 females) at 40 locations across the species range in China. The MANOVA results suggest significant sexual size dimorphism in C. versicolor (F 23,124 = 11.32, p < .001). Our results showed that C. versicolor failed to fit the Bergmann's rule. We found that the most important predictors of variation in body size of C. versicolor differed for males and females, but mechanisms related to heat balance and water availability hypotheses were involved in both sexes. Temperature seasonality, precipitation of the driest month, precipitation seasonality, and precipitation of the driest quarter were the most important predictors of variation in body size in males, whereas mean precipitation of the warmest quarter, mean temperature of the wettest quarter, precipitation seasonality, and precipitation of the wettest month were most important for body size variation in females. The discrepancy between patterns of association between the sexes suggested that different selection pressures may be acting in males and females.

Activity Patterns of Stenocercus iridescens in an Ecuadorian Coastal Agroecosystem: Is Temperature Important?

“…Dehydration negatively affected thermoregulation and dehydrated lizards reduced their preferred body temperature and showed a species-specific pattern of hourly change in thermal preference. Furthermore, they more frequently used the colder parts of the gradients and spent more time hidden [36,38]. Something similar could explain Stenocercus iridescens' low records when heliophany was higher (noon) during the dry season (Figure 3).…”

Reproductive cycle and maturation of Swinhoe’s tree lizard (<i>Diploderma swinhonis</i> (Günther, 1864)) in Hyuga City, Miyazaki Prefecture, Japan

“…The observation that D. swinhonis specimens from Hyuga City had a higher average BMI than specimens in Taiwan suggests that the nutritional status of the introduced D. swinhonis population in Hyuga City is better than that of lizards in Taiwan. The smaller mean SVL observed in lizards from Hyuga City is contrary to Bergman's rule, but exceptions to the rule have been reported in some ectothermal animals [21,25,32]. While the underlying reasons for such exceptions are not completely understood, it is reasonable to assume that a decrease in body size may be an adaptation to colder climates [21].…”

Road mortality of an Oriental Garden Lizard, Calotes versicolor (Daudin 1802)

“…E ssentially all terrestrial animals are vulnerable to road mortality or habitat fragmentation by roads (Rytwinski and Fahrig 2015;Hatti and Mubeen 2019) and road mortality is responsible for population declines in some reptilian species that live in close proximity to humans (Todd et al 2010). The Oriental Garden Lizard (Calotes versicolor) is a widely distributed agamid that ranges from Oman across southern and southeastern Asia to Indo-China, the Maldives, Réunion, Mauritius, and the Seychelles (Wei et al 2018). These lizards are very adaptable and often occur in human-altered environments and areas of human habitation (Sudasinghe and Somaweera 2015).…”