Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
Low temperature tolerance in insects : interactions with ambient gases
Thesis (PhD)--Stellenbosch University, 2013.
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Language: | en_ZA |
| Published: |
Stellenbosch : Stellenbosch University
2013
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613879498964992 |
|---|---|
| access_status_str | Open Access |
| author | Boardman, Leigh |
| author2 | Terblanche, J. S. |
| author_browse | Boardman, Leigh Terblanche, J. S. |
| author_facet | Terblanche, J. S. Boardman, Leigh |
| author_sort | Boardman, Leigh |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (PhD)--Stellenbosch University, 2013. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/95483 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:43:09.148Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/95483 Low temperature tolerance in insects : interactions with ambient gases Boardman, Leigh Terblanche, J. S. Sorensen, Jesper G. Stellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology. Insects -- Physiology -- Climatic factors Insects -- Effect of atmospheric carbon dioxide on Thaumatotibia leucotreta -- Effect of temperature on Insects -- Effect of insecticides on False codling moth -- Effect of stress on Gases UCTD Thesis (PhD)--Stellenbosch University, 2013. ENGLISH ABSTRACT: Understanding the mechanisms of low temperature tolerance, and determining the conditions from which cellular damage may be repaired or is irreversible, is critical to insect pest control. Insect low temperature tolerance depends on the insects’ basal ability to withstand or repair the stress associated with low temperature exposure, or the ability to develop biochemical protection. Changes may be induced at the whole-animal level (e.g. respiration rate, water balance), or at the molecular level (e.g. induction of cryoprotective metabolites and proteins). Post-harvest low temperature disinfestation treatments can be augmented with controlled atmospheres treatments (CAT, e.g. low oxygen and/or high carbon dioxide) to improve their efficacy at ridding commodities of pests. Theoretically, the potential overlaps in the mechanisms which insects can use to counteract low temperature and CAT may result in cross tolerance. Research presented in this dissertation aimed to i) determine important baseline knowledge related to low temperature and gas stress, ii) identify potential mechanisms underlying low temperature and gas tolerance, iii) identify potential commonalities in cellular and molecular stress responses between gas and temperature stress, and iv) investigate whether fluctuating stressors resulted in protection or accumulated damage in an economic pest insect of southern Africa, false codling moth Thaumatotibia leucotreta. Results for low temperature tolerance showed that larvae were chill-susceptible and die upon freezing. In response to hypoxia (low oxygen, whole-animal oxygen limitation), behaviour and metabolic rate were affected, while low temperature tolerance remained unchanged. While the results were equivocal regarding the identification of mechanisms underlying insect low temperature tolerance and cross tolerance with CAT, multiple non-lethal stress exposures (e.g. pretreatments with low temperatures and hypoxia) gave larvae a higher tolerance to low temperatures mediated by overlaps between the underlying cellular and molecular responses. Lastly, fluctuating stressors were protective when compared to constant stress conditions, likely through regulation of whole-animal metabolic rate and heat shock protein 70. In conclusion, a fundamental understanding of T. leucotreta low temperature tolerance and the interactions with other environmental stressors has been obtained, and the efficacy of combining organism ecology, physiology and molecular biology research with applied aspects to make informed decisions regarding pest management strategies has been demonstrated. AFRIKAANSE OPSOMMING: Bepaling van die toestande waaronder sellulêre beskadiging steeds herstelbaar is of onomkeerbaar is, is noodsaaklik vir die suksesvolle beheer van pes insekte. Insek lae temperatuur toleransie is afhanklik van die insek se basiese vermoë om die stres geassosieer met lae temperatuur blootstelling te hanteer, te herstel of biochemiese beskerming te ontwikkel. Veranderinge kan veroorsaak word op die hele-dier vlak (bv. asemhalingstempo, waterbalans), of op molekulêre vlak (bv. ontwikkeling van kriobeskermende metaboliete en proteïene). Om die doeltreffendheid van pes beheer in kommoditeite te verbeter kan na-oes lae temperatuur ontsmettingsbehandelinge aangevul word met gekontroleerde atmosfeer behandelinge (GAB, bv. lae suurstof en/of verhoogde koolstofdioksied). Die potensiële oorvleueling in die meganismes wat insekte gebruik om lae temperatuur en GAB teen te werk kan teoreties lei tot kruis-toleransie. Navorsing voorgelê in hierdie verhandeling beoog om i) belangrike basiese kennis met betrekking tot lae temperatuur en gas stres te bepaal, ii) om potensiële onderliggende meganismes van lae temperatuur en gas toleransie te identifiseer, iii) om potensiële ooreenstemmende sellulêre en molekulêre stres reaksies tussen gas en temperatuur stres te identifiseer, en iv) om vas te stel of wisselende stressors lei tot beskerming of geakkumuleerde skade in ‘n ekonomiese pes insek van suidelike Afrika, die valskodlingmot Thaumatotibia leucotreta. Lae temperatuur toleransie resultate het getoon dat larwes sensitief is vir koueblootstelling en sterf op bevriesing. In teenwerking van hipoksie (verlaagde suurstof, hele-dier suurstof beperking), was gedrag en metaboliese tempo beïnvloed, terwyl lae temperatuur toleransie onveranderd gebly het. Alhoewel resultate om die onderliggende meganismes van insek lae temperatuur toleransie en kruis-toleransie met GAB te identifiseer betwyfelbaar was, het larwes ‘n verhoogde toleransie tot lae temperature gehad na verskeie blootstellings aan nie-dodelike stres (bv. voor-behandelings met lae temperatuur en hipoksie), bemiddel deur die oorvleueling van onderliggende sellulêre en molekulêre reaksies. Laastens, wisselende stresvolle toestande was meer beskermend as konstante stres toestande, waarskynlik as gevolg van die beheer van hele-dier metaboliese tempo en hitte-skok proteïen 70. Ten slotte, ‘n fundamentele begrip van T. leucotreta lae temperatuur toleransie en interaksies met omgewings stressors is verkry. Die doeltreffendheid daarvan om navorsing oor organisme ekologie, fisiologie en molekulêre biologie met toegepaste aspekte te kombineer om ingeligte besluite te maak ten opsigte van pes beheer is getoon. Doctoral 2013-10-03T08:21:06Z 2014-01-21T09:25:34Z 2014-07-10T09:35:41Z 2013-10-03T08:21:06Z 2014-01-21T09:25:34Z 2013-12 Thesis http://hdl.handle.net/10019.1/95483 en_ZA Stellenbosch University 251 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Insects -- Physiology -- Climatic factors Insects -- Effect of atmospheric carbon dioxide on Thaumatotibia leucotreta -- Effect of temperature on Insects -- Effect of insecticides on False codling moth -- Effect of stress on Gases UCTD Boardman, Leigh Low temperature tolerance in insects : interactions with ambient gases |
| title | Low temperature tolerance in insects : interactions with ambient gases |
| title_full | Low temperature tolerance in insects : interactions with ambient gases |
| title_fullStr | Low temperature tolerance in insects : interactions with ambient gases |
| title_full_unstemmed | Low temperature tolerance in insects : interactions with ambient gases |
| title_short | Low temperature tolerance in insects : interactions with ambient gases |
| title_sort | low temperature tolerance in insects interactions with ambient gases |
| topic | Insects -- Physiology -- Climatic factors Insects -- Effect of atmospheric carbon dioxide on Thaumatotibia leucotreta -- Effect of temperature on Insects -- Effect of insecticides on False codling moth -- Effect of stress on Gases UCTD |
| url | http://hdl.handle.net/10019.1/95483 |
| work_keys_str_mv | AT boardmanleigh lowtemperaturetoleranceininsectsinteractionswithambientgases |