Summary
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.
Article navigation
Related articles
Cited by...
Similar articles
Other journals from The Company of Biologists
Editorial – The changing of the guard
In his Editorial, Hans Hoppeler announces that he will be stepping down as Editor-in-Chief of JEB in July 2020. He reflects on the history of JEB, why he has enjoyed his tenure as JEB’s Editor-in-Chief and the recent developments in the publishing world.
Editors’ choice – Parental stressor exposure simultaneously conveys both adaptive and maladaptive larval phenotypes through epigenetic inheritance in the zebrafish (Danio rerio)
An oil spill is never a good thing, but Naim Bautista and Warren Burggren have shown that zebrafish can pass on resistance to the damaging effects of an oil-spiked diet to their offspring.
The derivative of force with respect to time does not have a standard term in physics. In their new Commentary, David C. Lin and his colleagues propose that the term ‘yank’ should be used to denote the time derivative of force.
Runners waste energy every time their legs stop swinging, but now a team of scientists from the US and Canada have shown that a springy ankle tether can reduce runners’ energy costs by 6.4%, which is nearly the entire cost of swinging the limbs. Read the full research article here.
Journal of Experimental Biology is pleased to announce a new partnership with Publons! This allows reviewers to easily track and verify every review by choosing to add the review to their Publons profile when completing the review submission form. Publons also makes it simple for reviewers to showcase their peer review contributions in a format that can be included in job and funding applications (without breaking reviewer anonymity). Read the official announcement here!
The Company of Biologists provides grants to fund scientific meetings, workshops and conferences in the fields covered by our journals. Typically, meetings with fewer than 100 people may be granted up to £2,000, increasing up to £6,000 for about 400 people. The next deadline to apply is 28 November 2019.
preLights – preLights reaches 500 posts!
The success of preLights is down to the hard work of our preLighters. Head over to the preLights website to find out more about our most active early-career-researchers.