Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

The Cryptic Origins of Environment-Indicating Phantom Midges ("Chaoborus")

Derrick D. Dupuis, Jan-Erik Svensson and Derek J. Taylor
Limnology and Oceanography
Vol. 53, No. 1 (Jan., 2008), pp. 236-243
Stable URL: http://www.jstor.org/stable/40006164
Page Count: 8
  • More info
  • Cite this Item
The Cryptic Origins of Environment-Indicating Phantom Midges ("Chaoborus")
Preview not available

Abstract

Fragile freshwater ecosystems have acted as important sentinels for global environmental change. A detailed understanding of the implications of global change in aquatic ecosystems relies on indicator species whose body parts are preserved in aquatic sediments for millennia. The phantom midge, "Chaoborus flavicans" (Meigen, 1830), for example, has well-preserved mandibles in aquatic sediments and may act as an indicator of boreal zone temperatures, lake depth, and the presence of fish. Nevertheless, we report that "Chaoborus" with "C. flavicans"-type mandibles are common in fishless tundra ponds above the tree line in western Alaska. We carried out genetic comparisons of nuclear and mitochondrial deoxyribonucleic acid (mtDNA) sequences in "Chaoborus" at a Holarctic scale to determine the origins of the Alaskan "C. flavicans". Nuclear DNA, mtDNA, and morphological results indicated that the Alaskan "C. flavicans" represents a unique lineage of "Chaoborus". The average mtDNA divergence (Kimura's two-parameter) between the Palearctic "C. flavicans" and the Alaskan "C. flavicans" was >17%. mtDNA strongly supported "Chaoborus crystallinus" (De Geer, 1776) as the sister species to the Alaskan "C. flavicans". Our present understanding of larval mandible morphology disagrees with the major ecological properties and evolutionary lineages of "Chaoborus". We identify a new mandible character and highlight the value of validating the diagnostic morphologies of environmental indicator species with genetic studies.

Page Thumbnails

  • Thumbnail: Page 
236
    236
  • Thumbnail: Page 
237
    237
  • Thumbnail: Page 
238
    238
  • Thumbnail: Page 
239
    239
  • Thumbnail: Page 
240
    240
  • Thumbnail: Page 
241
    241
  • Thumbnail: Page 
242
    242
  • Thumbnail: Page 
243
    243