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A hierarchy of factors influence discontinuous gas exchange in the grasshopper Paracinema tricolor (Orthoptera: Acrididae)

dc.contributor.authorGroenewald, Berlizeen_ZA
dc.contributor.authorChown, Steven L.en_ZA
dc.contributor.authorTerblanche, John S.en_ZA
dc.date.accessioned2016-10-07T09:27:53Z
dc.date.available2016-10-07T09:27:53Z
dc.date.issued2014-07
dc.identifier.citationGroenewald, B., Chown, S. L. & Terblanche, J. S. 2014. A hierarchy of factors influence discontinuous gas exchange in the grasshopper Paracinema tricolor (Orthoptera: Acrididae). Journal of Experimental Biology, 217:3407-3415, doi:10.1242/jeb.1028143407.
dc.identifier.issn1477-9145 (online)
dc.identifier.issn0022-0949 (print)
dc.identifier.otherdoi:10.1242/jeb.1028143407
dc.identifier.urihttp://hdl.handle.net/10019.1/99709
dc.descriptionCITATION: Groenewald, B., Chown, S. L. & Terblanche, J. S. 2014. A hierarchy of factors influence discontinuous gas exchange in the grasshopper Paracinema tricolor (Orthoptera: Acrididae). Journal of Experimental Biology, 217:3407-3415, doi:10.1242/jeb.1028143407.
dc.descriptionThe original publication is available at http://jeb.biologists.org
dc.description.abstractThe evolutionary origin and maintenance of discontinuous gas exchange (DGE) in tracheate arthropods are poorly understood and highly controversial. We investigated prioritization of abiotic factors in the gas exchange control cascade by examining oxygen, water and haemolymph pH regulation in the grasshopper Paracinema tricolor. Using a full-factorial design, grasshoppers were acclimated to hypoxic or hyperoxic (5% O2, 40% O2) gas conditions, or dehydrated or hydrated, whereafter their CO2 release was measured under a range of O2 and relative humidity (RH) conditions (5%, 21%, 40% O2 and 5%, 60%, 90% RH). DGE was significantly less common in grasshoppers acclimated to dehydrating conditions compared with the other acclimations (hypoxia, 98%; hyperoxia, 100%; hydrated, 100%; dehydrated, 67%). Acclimation to dehydrating conditions resulted in a significant decrease in haemolymph pH from 7.0±0.3 to 6.6±0.1 (mean ± s.d., P=0.018) and also significantly increased the open (O)-phase duration under 5% O2 treatment conditions (5% O2, 44.1±29.3 min; 40% O2, 15.8±8.0 min; 5% RH, 17.8±1.3 min; 60% RH, 24.0±9.7 min; 90% RH, 20.6±8.9 min). The observed acidosis could potentially explain the extension of the O-phase under low RH conditions, when it would perhaps seem more useful to reduce the O-phase to lower respiratory water loss. The results confirm that DGE occurrence and modulation are affected by multiple abiotic factors. A hierarchical framework for abiotic factors influencing DGE is proposed in which the following stressors are prioritized in decreasing order of importance: oxygen supply, CO2 excretion and pH modulation, oxidative damage protection and water savings.en_ZA
dc.description.urihttp://jeb.biologists.org/content/217/19/3407
dc.format.extent9 pages : illustrationsen_ZA
dc.language.isoen_ZAen_ZA
dc.publisherThe Company of Biologists
dc.subjectParacinema tricoloren_ZA
dc.subjectDiscontinuous gas exchangeen_ZA
dc.subjectpH regulationen_ZA
dc.subjectOxidative damageen_ZA
dc.subjectWater regulationen_ZA
dc.titleA hierarchy of factors influence discontinuous gas exchange in the grasshopper Paracinema tricolor (Orthoptera: Acrididae)en_ZA
dc.typeArticleen_ZA
dc.description.versionPublisher's version
dc.rights.holderThe Company of Biologists


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