The closed spiracle phase of discontinuous gas exchange predicts diving duration in the grasshopper Paracinema tricolor

J Exp Biol. 2016 Aug 15;219(Pt 16):2423-5. doi: 10.1242/jeb.135129. Epub 2016 Jun 13.

Abstract

The discontinuous gas exchange (DGE) pattern of respiration shown by many arthropods includes periods of spiracle closure (C-phase) and is largely thought to serve as a physiological adaptation to restrict water loss in terrestrial environments. One major challenge to this hypothesis is to explain the presence of DGE in insects in moist environments. Here, we show a novel ecological correlate of the C-phase, namely, diving behaviour in mesic Paracinema tricolor grasshoppers. Notably, maximal dive duration is positively correlated with C-phase length, even after accounting for mass scaling and absolute metabolic rate. Here, we propose that an additional advantage of DGE may be conferred by allowing the tracheal system to act as a sealed underwater oxygen reservoir. Spiracle closure may facilitate underwater submersion, which, in turn, may contribute to predator avoidance, the survival of accidental immersion or periodic flooding and the exploitation of underwater resources.

Keywords: CT scan; Orthoptera; Respiratory gas exchange; Scaling; Submersion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Behavior, Animal
  • Carbon Dioxide / metabolism
  • Diving / physiology*
  • Gases / metabolism*
  • Grasshoppers / anatomy & histology*
  • Grasshoppers / metabolism*
  • Male
  • Respiratory Physiological Phenomena

Substances

  • Gases
  • Carbon Dioxide

Associated data

  • figshare/figshare.com/s/b5660399a0c5203b9a80