Morphotype Bias, Morph Specific Recruitment and No Elevation-Life History Relation in High Altitude Mesquite Lizard...

Across a species' distribution, environmental conditions vary, exposing populations to distinct ecological pressures. High-elevation sites exemplify such environments, where reptiles face harsher conditions that may interact with other sources of variation, such as morphotypes (alternative color phenotypes). Investigating life history traits of these populations is essential to understanding how organisms persist under environmental stress and how morphotypes contribute to that persistence. We analyzed three high-elevation populations of the mesquite lizard (Sceloporus grammicus Wiegmann, 1828), a widely distributed polymorphic lizard. We marked and monitored 1198 individuals during the 2017-2018 activity seasons and collected reproductive data from 60 females and 82 neonates. Using these data, we parameterized Pradel and linear models to estimate survival, recruitment and population growth rate, relative litter mass and newborn traits. In 2024, we conducted an additional survey of 274 individuals to fit N-mixture models to corroborate abundance trends. Contrary to life history theory, we have not detected altitudinal trends in reproductive traits, survival, or population growth within the altitude range studied. Instead, we found morphotype influenced recruitment and population growth rate, particularly in the highest-elevation population, where yellow females showed higher recruitment. Populations previously reported as within the same genetic cluster shared similar traits, suggesting a role for genetic structure over elevation. The only consistent pattern across all populations was a strong bias toward yellow morphotypes, especially in sites 1 and 2. Our findings indicate morphotype bias, only explained by recruitment in one site and no relation between life history and elevation in these high elevation populations.