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

Area of Science:

• Comparative physiology
• Ecogeography
• Herpetology

Background:

• Ecogeographical patterns predict phenotypic variation across environments.
• High-altitude adaptations often involve elevated hematological values due to lower oxygen pressure.
• Replicated studies on ecophysiological patterns, particularly in lizards, are scarce, leading to mixed support for altitude-related blood trait changes.

Purpose of the Study:

• To investigate the repeatability of ecogeographical patterns in lizard blood traits across replicated elevational gradients.
• To compare hematological values in mesquite lizards ( *Yatesia yaquensis* ) across low, medium, and high altitudes in three distinct mountain ranges.
• To determine if observed blood trait patterns are consistent across mountains or if they represent local phenomena.

Main Methods:

• Field sampling of mesquite lizards across elevational gradients in three mountains of the Trans-Mexican Volcanic Belt.
• Measurement of key blood parameters: hematocrit, hemoglobin concentration, mean corpuscular hemoglobin concentration, and erythrocyte size.
• Statistical comparison of blood traits between different elevations and among the three mountain systems.

Main Results:

• Consistent elevational patterns in blood traits were observed across the studied mountains.
• Lizards at middle altitudes displayed higher oxygen-carrying capacity compared to those at low and high altitudes.
• Significant differences in blood traits were detected among the different mountain systems, despite similar elevational trends.

Conclusions:

• Replication revealed consistent elevational trends in lizard blood traits, with middle-altitude populations showing enhanced oxygen transport.
• Variations in blood traits among mountain systems suggest the influence of local factors, potentially through phenotypic plasticity or genetic differentiation.
• Further research is needed to elucidate the specific abiotic factors driving these inter-mountain differences in ecophysiological adaptations.