Intra-individual variation allows an explicit test of the hygric hypothesis for discontinuous gas exchange in insects

Caroline M. Williams, Shannon L. Pelini, Jessica J. Hellmann, Brent J. Sinclair

Research output: Contribution to journalArticle

34 Scopus citations

Abstract

The hygric hypothesis postulates that insect discontinuous gas exchange cycles (DGCs) are an adaptation that reduces respiratory water loss (RWL), but evidence is lacking for reduction of water loss by insects expressing DGCs under normal ecological conditions. Larvae of Erynnis propertius (Lepidoptera: Hesperiidae) naturally switch between DGCs and continuous gas exchange (CGE), allowing flow-through respirometry comparisons of water loss between the two modes. Water loss was lower during DGCs than CGE, both between individuals using different patterns and within individuals using both patterns. The hygric cost of gas exchange (water loss associated with carbon dioxide release) and the contribution of respiratory to total water loss were lower during DGCs. Metabolic rate did not differ between DGCs and CGE. Thus, DGCs reduce RWL in E. propertius, which is consistent with the suggestion that water loss reduction could account for the evolutionary origin and/or maintenance of DGCs in insects.

Original languageEnglish (US)
Pages (from-to)274-277
Number of pages4
JournalBiology letters
Volume6
Issue number2
DOIs
StatePublished - Apr 23 2010
Externally publishedYes

Keywords

  • Discontinuous gas exchange
  • Lepidoptera
  • Respiratory water loss

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