Image: Heteromeles arbutifolia (Toyon), a common chaparral shrub in California. Plant secondary chemistry differs between populations on the California mainland and the nearby Channel Islands.
Image: Monarchs from Puerto Rico (left) and North America (right) reared under common greenhouse conditions
Image: A monarch butterfly nectaring on A. curassavica in Guam. Monarchs were first recorded in Guam in 1887.
Monarchs are originally from Central and North America but can now be found around the world. When and why did this range expansion occur? How are these populations related to one another?
Monarchs feed on milkweed plants as caterpillars. How do cardenolides (toxic secondary compounds) produced by milkweeds influence monarchs and their interactions with natural enemies?
How does migration affect the size and shape of monarch wings? Can we see contemporary evolution of wing size and shape in non-migratory monarchs?
PNASTwo centuries of monarch butterfly collections reveal contrasting effects of range expansion and migration loss on wing traits
Preprints (currently in review)Are Eastern and Western Monarch Butterflies Distinct Populations? A Review of Evidence for Ecological, Phenotypic, and Genetic Differentiation and Implications for Conservation
EvolutionHost plant adaptation during contemporary global range expansion in the monarch butterfly
Animal MigrationWing morphology in migratory North American monarchs: characterizing sources of variation and understanding changes through time
Research featured in National Geographic
OecologiaLandscape-level bird loss increases the prevalence of honeydew-producing insects and non-native ants
Biological Journal of the Linnean SocietyNon-migratory monarchs, Danaus plexippus (L.), retain developmental plasticity and a navigational mechanism associated with migration