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Oecologia

, Volume 120, Issue 3, pp 397–404 | Cite as

Stable isotopes (δD and δ13C) are geographic indicators of natal origins of monarch butterflies in eastern North America

  • Keith A. Hobson
  • Leonard I. Wassenaar
  • Orley R. Taylor
Article

Abstract

Wing membranes of laboratory and field-reared monarch butterflies (Danaus plexippus) were analyzed for their stable-hydrogen (δD) and carbon (δ13C) isotope ratios to determine whether this technique could be used to identify their natal origins. We hypothesized that the hydrogen isotopic composition of monarch butterfly wing keratin would reflect the hydrogen isotope patterns of rainfall in areas of natal origin where wings were formed. Monarchs were reared in the laboratory on milkweed plants (Asclepias sp.) grown with water of known deuterium content, and, with the assistance of volunteers, on native milkweeds throughout eastern North America. The results show that the stable hydrogen isotopic composition of monarch butterflies is highly correlated with the isotopic composition of the milkweed host plants, which in turn corresponds closely with the long-term geographic patterns of deuterium in rainfall. Stable-carbon isotope values in milkweed host plants were similarly correlated with those values in monarch butterflies and showed a general pattern of enrichment along a southwest to northeast gradient bisecting the Great Lakes. These findings indicate that natal origins of migratory and wintering monarchs in Mexico can be inferred from the combined δD and δ13C isotopic signatures in their wings. This relationship establishes that analysis of hydrogen and carbon isotopes can be used to answer questions concerning the biology of migratory monarch butterflies and provides a new approach to tracking similar migratory movements of other organisms.

Key words Monarch butterfly Migration Natal origins Isotopic gradients 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • Keith A. Hobson
    • 1
  • Leonard I. Wassenaar
    • 2
  • Orley R. Taylor
    • 3
  1. 1.Environment Canada, Prairie and Northern Wildlife Research Center, 115 Perimeter Rd., Saskatoon, Saskatchewan, S7N 0X4, Canada e-mail: keith.hobson@ec.gc.caCA
  2. 2.Environment Canada, National Hydrology Research Center, 11 Innovation Blvd., Saskatoon, Saskatchewan, S7N 3H5, CanadaCA
  3. 3.Department of Entomology, Monarch Watch, University of Kansas, Lawrence, KS 66045, USAUS

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