Uncovering spring migration patterns in the monarch butterfly (Danaus plexippus) using stable isotopes



Miller, Nathan

Journal Title

Journal ISSN

Volume Title


University of Guelph


Despite the massive scale of annual insect migrations in terms of sheer biomass, remarkably little is known about how individuals and populations are geographically connected between breeding sites. In chapter 1, I use stable isotopes of hydrogen ([delta]D) coupled with a measure of wing wear and a simulation model of emergence dates to estimate the natal origins of monarchs collected throughout the Great Lakes region and in doing so test two century old re-colonization hypotheses. I found that 25% of monarchs utilize a 'single sweep' strategy by migrating from overwintering sites in Mexico, while the majority of re-colonization is accomplished by the 1 st spring generation, termed the 'successive brood' strategy. In chapter 2, I use stable isotopes of hydrogen and carbon ([delta]13C) to estimate natal origins of monarchs collected across the east coast of the U.S. Supporting Brower's 1996 'range expansion' hypothesis, I found that 88% of monarchs re-colonized this region by migrating eastward across the Appalachians. My results provide critical information necessary for developing models to predict long-term changes in population abundance throughout the eastern monarch breeding range and for designating areas of high conservation priority for this species of special concern.



monarch butterfly, Danaus plexippus, migration patterns, spring, stable isotopes, conservation priority