The effect of oxygen limitation on a xylophagous insect's heat tolerance is influenced by life-stage through variation in aerobic scope and respiratory anatomy

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dc.contributor.authorJaval, Marionen_ZA
dc.contributor.authorThomas, Saskiaen_ZA
dc.contributor.authorLehmann, Philippen_ZA
dc.contributor.authorBarton, Madeleine G.en_ZA
dc.contributor.authorConlong, Desmond E.en_ZA
dc.contributor.authorDu Plessis, Antonen_ZA
dc.contributor.authorTerblanche, John S.en_ZA
dc.date.accessioned2020-01-16T09:22:34Z
dc.date.accessioned2021-08-25T15:51:57Z
dc.date.available2020-01-16T09:22:34Z
dc.date.available2021-08-25T15:51:57Z
dc.date.issued2019-11-20
dc.descriptionCITATION: Javal, M. et al. 2019. The effect of oxygen limitation on a xylophagous insect's heat tolerance is influenced by life-stage through variation in aerobic scope and respiratory anatomy. Frontiers in Physiology, 10:1426, doi: 10.3389/fphys.2019.01426.
dc.description.abstractENGLISH ABSTRAT: Temperature has a profound impact on insect fitness and performance via metabolic, enzymatic or chemical reaction rate effects. However, oxygen availability can interact with these thermal responses in complex and often poorly understood ways, especially in hypoxia-adapted species. Here we test the hypothesis that thermal limits are reduced under low oxygen availability - such as might happen when key life-stages reside within plants - but also extend this test to attempt to explain that the magnitude of the effect of hypoxia depends on variation in key respiration-related parameters such as aerobic scope and respiratory morphology. Using two life-stages of a xylophagous cerambycid beetle, Cacosceles (Zelogenes) newmannii we assessed oxygen-limitation effects on metabolic performance and thermal limits. We complement these physiological assessments with high-resolution 3D (micro-computed tomography scan) morphometry in both life-stages. Results showed that although larvae and adults have similar critical thermal maxima (CTmax) under normoxia, hypoxia reduces metabolic rate in adults to a greater extent than it does in larvae, thus reducing aerobic scope in the former far more markedly. In separate experiments, we also show that adults defend a tracheal oxygen (critical) setpoint more consistently than do larvae, indicated by switching between discontinuous gas exchange cycles (DGC) and continuous respiratory patterns under experimentally manipulated oxygen levels. These effects can be explained by the fact that the volume of respiratory anatomy is positively correlated with body mass in adults but is apparently size-invariant in larvae. Thus, the two life-stages of C. newmannii display key differences in respiratory structure and function that can explain the magnitude of the effect of hypoxia on upper thermal limits.en_ZA
dc.description.versionPublisher's version
dc.format.extent11 pages : illustrationsen_ZA
dc.identifier.citationJaval, M., Thomas, S., Lehmann, P., Barton, M.G., Conlong, D.E., Du Plessis, A. and Terblanche, J.S. (2019). The effect of oxygen limitation on a xylophagous insect's heat tolerance is influenced by life-stage through variation in aerobic scope and respiratory anatomy. Frontiers in Physiology 10, 1426, 11 pages. DOI: 10.3389/fphys.2019.01426.en_ZA
dc.identifier.issn1664-042X
dc.identifier.urihttp://hdl.handle.net/10019.1/113598
dc.language.isoenen_ZA
dc.publisherFrontiers
dc.rights.holderAuthors retain copyright
dc.subject.lcshCacosceles newmannii -- Ecologyen_ZA
dc.subject.lcshInsects -- Effect of temperature onen_ZA
dc.subject.lcshInsects -- Effect of chemicals onen_ZA
dc.subject.lcshInsects -- Respirationen_ZA
dc.subject.lcshOxygen -- Physiological effect -- Measurementen_ZA
dc.subject.lcshRespiration -- Animal modelsen_ZA
dc.subject.lcshHypoxiaen_ZA
dc.titleThe effect of oxygen limitation on a xylophagous insect's heat tolerance is influenced by life-stage through variation in aerobic scope and respiratory anatomyen_ZA
dc.typeArticleen_ZA
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