Bluer in the city: urban male lizards exhibit more intense sexual coloration and lower parasite loads than non-urban males.

Urbanization is a global phenomenon that involves the transformation of natural areas into urban spaces, thereby subjecting organisms to new selective pressures including a wide variety of pollutants and changes in intra- and interspecific interactions. Considering that projections indicate that by the year 2050, 65% of the human population will live in urban areas and that urbanization is a phenomenon with an upward pattern, identifying these phenotypic traits is vital to implementing conservation and management plans for urban fauna. The urban environment may exert different selective pressures on sexually selected traits than more pristine environments, a phenomenon which has been well studied in birds but is less understood in other vertebrates such as lizards, although they are common inhabitants of urban environments.

Seasonal and altitudinal variation in dorsal skin reflectance and thermic rates in a high-altitude montane lizard.

Temperature is one of the most important factors in the life histories of ectotherms, as body temperature has an undeniable effect on growth, activity, and reproduction. Lizards have a wide variety of strategies to acquire and maintain body temperature in an optimal range. The "Thermal Melanism Hypothesis" proposes that individuals with lower skin reflectance can heat up faster as a result of absorbing more solar radiation compared to lighter conspecifics.

Thermoregulatory behavior varies with altitude and season in the sceloporine mesquite lizard.

In ectothermic animals, body temperature is the most important factor affecting physiology and behavior. Reptiles depend on environmental temperature to regulate their body temperature, so geographic variation in environmental temperature can affect the biology of these organisms in the short and long term. We may expect physiological and behavioral responses to temperature change to be especially important in ectotherms inhabiting temperate zones, where different seasons present different thermal challenges.

Altitudinal variation in organ mass from three mountain systems: The case of mesquite lizard Sceloporus grammicus.

High altitude environments provide a fertile ground for investigating the benefits of phenotypic adjustments at several levels of biological organization. Low oxygen partial pressure and low environmental temperature are the main limiting factors that promote phenotypic variation in different organs, such as the lung and heart. Although high-altitude environments act like natural laboratories, most morphological studies conducted to date lack replication.

Elevation and blood traits in the mesquite lizard: Are patterns repeatable between mountains?

Ecogeographical patterns describe predictable variation in phenotypic traits between ecological communities. For example, high-altitude animals are expected to show elevated hematological values as an adaptation to the lower oxygen pressure. Mountains act like ecological islands and therefore are considered natural laboratories.