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.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Metabolic Changes during Estivation in the Common Earthworm Aporrectodea caliginosa

Mark Bayley, Johannes Overgaard, Andrea Sødergaard Høj, Anders Malmendal, Niels C. Nielsen, Martin Holmstrup and Tobias Wang
Physiological and Biochemical Zoology: Ecological and Evolutionary Approaches
Vol. 83, No. 3 (May/June 2010), pp. 541-550
DOI: 10.1086/651459
Stable URL: http://www.jstor.org/stable/10.1086/651459
Page Count: 10
  • Read Online (Free)
  • Download ($19.00)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Metabolic Changes during Estivation in the Common Earthworm Aporrectodea caliginosa
Preview not available

Abstract

Abstract The common earthworm Aporrectodea caliginosa survives drought by forming estivation chambers in the topsoil under even very slight reductions in soil water activity. We induced estivation in a soil of a consistency that allowed the removal of intact soil estivation chambers containing a single worm. These estivation chambers were exposed to 97% relative humidity for 30 d to simulate the effect of a severe summer drought. Gas exchange, body fluid osmolality, water balance, urea, and alanine were quantified, and whole‐body homogenates were screened for changes in small organic molecules via 1H–nuclear magnetic resonance (NMR). Formation of estivation chambers was associated with a dramatic increase in body fluid osmolality, from 175 to 562 mOsm kg−1, accompanied by a 20% increase in water content. Dehydration for 1 mo caused a further increase to 684 mOsm kg−1, while the worms lost 50% of their water content. Gas exchange was depressed by 50% after worms entered estivation and by 80% after a further 30 d of dehydration. Urea concentrations increased from 0.3 to 1 μmol g−1 dry mass during this time. Although 1H‐NMR did not provide the identity of the osmolytes responsible for the initial increase in osmolality after estivation, it showed that alanine increased to more than 80 mmol L−1 in the long‐term‐estivation group. We propose that alanine functions as a nitrogen depot during dehydration and is not an anaerobe product in this case.

Page Thumbnails

  • Thumbnail: Page 
1
    1
  • Thumbnail: Page 
2
    2
  • Thumbnail: Page 
3
    3
  • Thumbnail: Page 
4
    4
  • Thumbnail: Page 
5
    5
  • Thumbnail: Page 
6
    6
  • Thumbnail: Page 
7
    7
  • Thumbnail: Page 
8
    8
  • Thumbnail: Page 
9
    9
  • Thumbnail: Page 
10
    10