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Variability among individuals and populations : implications for arthropod physiology

Dissertation (PhD)--University of Stellenbosch, 2006.

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Main Author: Terblanche, Jonathan Steed
Other Authors: Chown, Steven L.
Format: Thesis
Language:en_ZA
Published: Stellenbosch : Stellenbosch University 2012
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access_status_str Open Access
author Terblanche, Jonathan Steed
author2 Chown, Steven L.
author_browse Chown, Steven L.
Terblanche, Jonathan Steed
author_facet Chown, Steven L.
Terblanche, Jonathan Steed
author_sort Terblanche, Jonathan Steed
collection Thesis
dc_rights_str_mv Stellenbosch University
description Dissertation (PhD)--University of Stellenbosch, 2006.
format Thesis
id oai:scholar.sun.ac.za:10019.1/21763
institution Stellenbosch University (South Africa)
language en_ZA
last_indexed 2026-06-10T12:41:31.332Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository
publishDate 2012
publishDateRange 2012
publishDateSort 2012
publisher Stellenbosch : Stellenbosch University
publisherStr Stellenbosch : Stellenbosch University
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source_str SUNScholar — Stellenbosch University Repository
spelling oai:scholar.sun.ac.za:10019.1/21763 Variability among individuals and populations : implications for arthropod physiology Terblanche, Jonathan Steed Chown, Steven L. Stellenbosch University. Faculty of Science. Dept. of Botany and Zoology. Arthropoda -- Physiology Arthropoda -- Variation Arthropod populations Tsetse-flies -- Physiology Tsetse-flies -- Variation Theses -- Zoology Dissertations -- Zoology Dissertation (PhD)--University of Stellenbosch, 2006. ENGLISH ABSTRACT: Within arthropods, inter-individual and inter-population variation is generally poorly explored for physiological parameters. Such physiological variability is important, as it can provide insight into the capacity for evolutionary adaptation and how animals may cope with anthropogenic climate change. Insect vectors of human and animal diseases, such as tsetse flies (Diptera, Glossinidae) which carry trypanosomes, are of particular interest. Predictions of tsetse fly (Glossina spp.) range expansion, possibly paralleled by increased disease occurrence, have been made under future climate scenarios. Moreover, since there are generally strong relationships between abiotic variables (e.g. temperature and moisture availability), population dynamics, distribution and abundance, determining the physiological mechanisms influencing such relationships has utility for predictive modelling of spatial and temporal changes in tsetse fly distributions. I investigated physiological variation among individuals and populations, focusing mainly on Glossina spp. but using other arthropods to address certain issues. Specifically, I show the following: i) metabolic rate is repeatable (intra-class correlation coefficient) within individuals, and may be influenced by several factors such as age, gender, body mass and pregnancy; ii) while metabolic rate is repeatable within individuals, it remains unaltered with acclimation to laboratory conditions from field collection; iii) within a population, metabolic rate-temperature relationships are surprisingly invariant among physiological states such as age, gender, feeding status, pregnancy and temperature acclimation; iv) the magnitude of the effect of temperature acclimation differs among traits, in that upper thermal tolerances respond less than lower thermal tolerances, while metabolic rate responds to heat but not to cold. Water loss rate is relatively unresponsive to either treatment; v) plasticity can account for most inter-population variation in physiological traits related to climatic stress resistance (e.g. thermotolerances and desiccation rates) in the natural environment; vi) adult physiological performance responds differently to developmental and adult acclimation, such that marked traitspecific variation occurs, and combinations of both developmental and adult plasticity can result in further alteration of adult performance. These results have implications for the evolution of stress resistance to abiotic factors in these and other arthropods. I conclude by discussing the potential physiological patterns linking population dynamics and abiotic factors, with particular reference to tsetse flies. AFRIKAANSE OPSOMMING: Binne arthropoda, is tussen-individu en tussen-bevolking variasie in die algemeen sleg bestudeer vir fisiologiese parameters. Hierdie fisiologiese variasie is belangrik want dit kan insig gee in die mate van evolusionêre aanpassing en hoe diere antropogenies klimaatsverandering kan hanteer. Dit is veral belangrik in die geval van insekte wat mens- en diersiektes kan dra, soos tsetse vlieë (Diptera, Glossinidae) wat trypanosome oordra. In die geval van tsetse vlieë (Glossina spp.) is voorspellings vir verhoogde verspreiding, en gevolglik verhoogde siekte voorkoms, gemaak onder toekomstige voorkoms klimaat senario’s. Verder, aangesien daar in die algemeen sterk verwantskappe tussen abiotiese parameters (bv. temperatuur en water beskikbaarheid), bevolkingsdynamika, verspreiding en voorkoms is, is die bepaling van die fisiologiese meganisme, wat ‘n invloed het op hierdie verwantskappe, nuttig vir die voorspelling van tsetse oor spasie en tyd. Hier, met hoofsaaklik die gebruik van Glossina spp., maar ook ander arthropoda wanneer dit nodig is, word navorsing wat fisiologiese variasie tussen individue en bevolkings aanspreel voorgelê. Spesifiek, word dit gewys dat i) metaboliese tempo is herhaalbaar (intra-klas korrelasie koeffisient) binne individue, alhowel metaboliese tempo kan beinvloed word deur faktore soos ouderdom, geslag, liggaamsmassa en swangerskap, ii) terwyl metaboliese tempo binne individue herhaalbaar is, verander dit nie met akklimasie na laboratorium toestande vanaf versameling in die veld, iii) binne ‘n bevolking metaboliese tempo-temperatuur verwantskappe is verbasend eenders tussen fisiologiese toestande soos ouderdom, geslag, voeding staat, swangerskap en temperatuur akklimasie, iv) die grootte van die effek van temperatuur akklimasie verskil tussen eienskappe, en die boonste termiese limiete reageer minder as laer termiese limiete, terwyl metaboliese tempo reageer op hitte maar nie koue nie, en waterverlies tempo is relatief terughoudend tot enige temperatuur toestand, v) buigbaarheid kan die meeste van inter-bevolkingsvariasie in fisiologiese eienskappe van klimaatstres weerstandsvermoë (termiese toleransie en uitdrogingstempo) in die natuurlike omgewing verklaar, vi) volwasse fisiologiese prestasie reageer verskillend op ontwikkelende en volwasse akklimasie, soveel dat eienskap-spesifieke variasie kan voorkom, en ‘n kombinasie van beide ontwikkelende en volwasse buigbaarheid ‘n verskillende volwasse prestasie tot gevolg kan hê. Hierdie resultate het implikasies vir die evolusie van weerstandsvermoë tot abiotiese faktore in hierdie en ander arthropoda. Hierdie tesis word afgesluit met ‘n bespreeking van die moontlikke fisiologiese patrone wat bevolkingsdinamika en abiotiese faktore kan verbind, met ‘n fokus op tsetse vlieë. Doctoral 2012-07-18T13:47:07Z 2012-07-18T13:47:07Z 2006-04 Thesis http://hdl.handle.net/10019.1/21763 en_ZA Stellenbosch University x, 254 leaves : ill. application/pdf Stellenbosch : Stellenbosch University
spellingShingle Arthropoda -- Physiology
Arthropoda -- Variation
Arthropod populations
Tsetse-flies -- Physiology
Tsetse-flies -- Variation
Theses -- Zoology
Dissertations -- Zoology
Terblanche, Jonathan Steed
Variability among individuals and populations : implications for arthropod physiology
title Variability among individuals and populations : implications for arthropod physiology
title_full Variability among individuals and populations : implications for arthropod physiology
title_fullStr Variability among individuals and populations : implications for arthropod physiology
title_full_unstemmed Variability among individuals and populations : implications for arthropod physiology
title_short Variability among individuals and populations : implications for arthropod physiology
title_sort variability among individuals and populations implications for arthropod physiology
topic Arthropoda -- Physiology
Arthropoda -- Variation
Arthropod populations
Tsetse-flies -- Physiology
Tsetse-flies -- Variation
Theses -- Zoology
Dissertations -- Zoology
url http://hdl.handle.net/10019.1/21763
work_keys_str_mv AT terblanchejonathansteed variabilityamongindividualsandpopulationsimplicationsforarthropodphysiology