Available at: https://digitalcommons.calpoly.edu/theses/3226
Date of Award
12-2025
Degree Name
MS in Biological Sciences
Department/Program
Biological Sciences
College
College of Science and Mathematics
Advisor
Jenn Yost
Advisor Department
Biological Sciences
Advisor College
College of Science and Mathematics
Abstract
Divergent selection across heterogeneous environments can drive ecological differentiation and the evolution of locally adapted populations, even when gene flow occurs. We tested for local adaptation between two sympatric monkeyflowers, Erythranthe guttata and E. serpentinicola (formerly Mimulus), which co-occur on the central coast of California. Erythranthe guttata is a perennial species primarily found in moist serpentine seeps, whereas E. serpentinicola is an annual species restricted to adjacent serpentine rock outcrops. Using a reciprocal transplant experiment with second-generation, greenhouse-derived seed, we quantified germination, survival, and reproductive success across contrasting microhabitats. We further evaluated the relative contributions of species, lineage, and fine-scale environmental variation to performance across life stages. Our findings reveal strong variation in early-life performance driven by lineage and plot-level heterogeneity but limited evidence for home-site advantage across habitats. Together with prior morphological and physiological studies, these results provide an expanded view on ecological divergence in sympatry. This can clarify the role of local adaptation in shaping patterns of differentiation within the E. guttata complex.