ScienceDaily (July 26, 2010) — Monarch butterflies -- renowned for their lengthy annual migration to and from Mexico -- complete an even more spectacular journey home than previously thought.
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Monarch butterfly (Danaus plexippus) migration. (Credit: iStockphoto/Jodi Jacobson)
New research from the University of Guelph reveals that some North American monarchs born in the Midwest and Great Lakes fly directly east over the Appalachians and settle along the eastern seaboard. Previously, scientists believed that the majority of monarchs migrated north directly from the Gulf coast.
The study appears in the recent issue of the scientific journal Biology Letters.
"It's a groundbreaking finding," said Ryan Norris, a Guelph professor in the Department of Integrative Biology who worked on the study with his graduate student Nathan Miller and two researchers from Environment Canada.
"It solves the long-standing mystery of why monarchs always show up later on the east coast compared to the interior," he said. "Importantly, it means that the viability of east coast populations is highly dependent upon productivity on the other side of the mountains."
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Read more here/Leia mais aqui: Science Daily
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Monarch butterflies cross the Appalachians from the west to recolonize the east coast of North America
-Author Affiliations
1Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
2Environment Canada, 11 Innovation Boulevard, Saskatoon, Saskatchewan, Canada S7N 3H5
- *Author for correspondence (nmiller@uoguelph.ca).
Abstract
Each spring, millions of monarch butterflies (Danaus plexippus) migrate from overwintering sites in Mexico to recolonize eastern North America. However, few monarchs are found along the east coast of the USA until mid-summer. Brower (Brower, L. P. 1996 J. Exp. Biol. 199, 93–103.) proposed that east coast recolonization is accomplished by individuals migrating from the west over the Appalachians, but to date no evidence exists to support this hypothesis. We used hydrogen (δD) and carbon (δ13C) stable isotope measurements to estimate natal origins of 90 monarchs sampled from 17 sites along the eastern United States coast. We found the majority of monarchs (88%) originated in the mid-west and Great Lakes regions, providing, to our knowledge, the first direct evidence that second generation monarchs born in June complete a (trans-) longitudinal migration across the Appalachian mountains. The remaining individuals (12%) originated from parents that migrated directly from the Gulf coast during early spring. Our results provide evidence of a west to east longitudinal migration and provide additional rationale for conserving east coast populations by identifying breeding sources.
Footnotes
- Received June 7, 2010.
- Accepted June 23, 2010.
- © 2010 The Royal Society
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