Condition, genotype-by-environment interaction, and correlational selection in lizard life-history morphs

Area of Science:

• Evolutionary Biology
• Behavioral Ecology
• Herpetology

Background:

• Side-blotched lizards (Uta stansburiana) exhibit heritable female throat color morphs (orange and yellow).
• Understanding how social environments and genetic variation influence reproductive allocation and fitness is crucial in wild populations.

Purpose of the Study:

• To compare reproductive allocation, condition, and survivorship between orange and yellow morphs of female Uta stansburiana.
• To investigate the impact of the social environment on clutch size, egg mass, and female condition.
• To explore how these traits affect female survival and fitness, considering genotype-by-environment interactions.

Main Methods:

• Path analysis and structural equation modeling were employed.
• Data were collected from a free-living population of Uta stansburiana.
• Reproductive traits, condition indicators (postlaying mass, immunological condition), and survivorship were measured.

Main Results:

• Both morphs increased clutch size with more neighbors; this was significant only in yellow morphs.
• Yellow morphs increased egg mass when near orange neighbors.
• Orange morphs showed immunosuppression near orange neighbors, while yellow morphs were less affected.
• Morphotype and immune response interactively affected fitness, indicating fitness epistasis and correlational selection.

Conclusions:

• Social environment and female morphotype significantly interact to influence reproductive allocation and fitness in Uta stansburiana.
• Morph-specific trade-offs and genotype-by-environment interactions shape life-history allocation and selection.
• Conspicuous genetic polymorphisms are valuable tools for studying selection and life-history evolution in natural settings.