Control of resting ventilation rate in grasshoppers

Scotti L. Gulinson, Jon Harrison

Research output: Contribution to journalArticle

36 Scopus citations

Abstract

We examined the effect of extracellular acid-base status and tracheal gas levels on the ventilation rate of resting Romalea guttata and Schistocerca americana grasshoppers. We manipulated haemolymph pH and [HCO3-] within normal physiological ranges using injections of HCl, NaOH, NaHCO3 and NaCl into the haemocoel. In contrast to terrestrial vertebrates, there was no evidence that extracellular acidification increases ventilation rate in grasshoppers. Elevation of haemolymph bicarbonate levels (by NaHCO3 injection) increased ventilation rate, while depression of haemolymph bicarbonate levels (HCl injection) had no effect. Injection of NaHCO3 also increased tracheal PCO2, suggesting that the effect of the NaHCO3 injection might be mediated by a sensitivity of the ventilatory system to tracheal gases. We tested for effects of tracheal gases on ventilation rate by independently manipulating tracheal PCO2 and PO2 using tracheal perfusions. Ventilation rate was positively correlated with tracheal PCO2 and negatively correlated with tracheal PO2. Increasing tracheal PO2 above normal resting levels or decreasing tracheal PCO2 below normal levels decreased ventilation rate. We conclude that quiescent grasshoppers regulate tracheal PCO2 and PO2 by varying ventilation rate and that both PCO2 and PO2 in the trachea stimulate ventilation in normal, resting grasshoppers.

Original languageEnglish (US)
Pages (from-to)379-389
Number of pages11
JournalJournal of Experimental Biology
Volume199
Issue number2
StatePublished - Feb 1 1996

Keywords

  • Grasshopper
  • Regulation of ventilation
  • Romalea guttata
  • Schistocerca americana
  • Ventilation
  • pH regulation

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Physiology
  • Aquatic Science
  • Animal Science and Zoology
  • Molecular Biology
  • Insect Science

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