Physiological phenotypes differ among color morphs in introduced common wall lizards (Podarcis muralis)

Area of Science:

• Ecology
• Evolutionary Biology
• Physiology

Background:

• Color polymorphism is common in many species, but trait covariation patterns across diverse contexts are not well understood.
• Understanding physiological traits is vital for invasion biology and urban adaptation, as they directly influence fitness and population establishment.
• Podarcis muralis lizards are a versatile color polymorphic species found in urban settings, including invasive populations.

Purpose of the Study:

• To investigate the physiological traits of Podarcis muralis color morphs in an urban environment.
• To test for variations in physiological phenotypes among co-occurring color morphs.
• To understand how morph-specific physiological strategies contribute to urban adaptation and establishment.

Main Methods:

• Measurement of five key physiological traits: plasma corticosterone, plasma triglycerides, hematocrit, body condition, and field body temperature.
• Analysis of an integrated multivariate phenotype across different color morphs.
• Assessment of seasonal variation in physiological traits among morphs within an urban ecological context.

Main Results:

• Significant differences in multivariate physiological phenotypes were observed between white and yellow morphs, primarily driven by plasma corticosterone levels.
• Physiological status and strategy varied seasonally in a morph-dependent manner, indicating distinct regulatory approaches.
• The white-yellow morph displayed an intermediate phenotype, suggesting a blended energy maintenance strategy, while orange morphs showed distinct but less interpretable phenotypes due to low prevalence.

Conclusions:

• Color morphs of Podarcis muralis possess distinct physiological strategies that are modulated seasonally.
• These morph-specific physiological differences are crucial for the species' successful adaptation and establishment in novel urban environments.
• The study highlights how variation within stable polymorphisms can facilitate adaptation to new ecological contexts.