Studies on the critical water mass, rehydration capability and potential, acute chill tolerance and supercooling point of Argas (Persicargas) walkerae (Acari: Argasidae)

dc.contributor.authorGothe, R.
dc.contributor.authorStark, Ulrike
dc.contributor.editorBoomker, Jacob Diederik Frederik
dc.date.accessioned2012-03-20T13:08:29Z
dc.date.available2012-03-20T13:08:29Z
dc.date.created2012
dc.date.issued2001
dc.descriptionThe articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.en
dc.description.abstractThe critical water mass, defined as the water mass remaining in a dehydrated tick in the non-ambulatory state, differed only slightly between light and heavy mass groups of Argas walkerae and averaged 23.6% and 23.2%, respectively, in males and 28.4% and 28.0%, respectively, in females. All ticks survived dehydration of 50%, 75% or 100% of their critical water mass, and 95% of them rehydrated during their subsequent incubation at 95% relative humidity (RH) and 28 degrees C for 14 days and regained their ambulatory status. Unfed adults were able to balance water loss frequently over a period of several months. When ticks were repeatedly dehydrated at 0% RH for 14 days, females and males suffered 50% mortality after 16 and 19 cycles of dehydration and rehydration, respectively, over a period of 278 days and 337 days, respectively. Water itself was not attractive to either dehydrated or non-dehydrated ticks and drinking was not observed. After submergence in water for 3 days, most of the dehydrated adult ticks gained mass. Judged by 50% mortality, larvae tolerated short-term extreme chilling to -24 degrees C, nymphs I to -22 degrees C, nymphs II to -20 degrees C, females and males to -19 degrees C. None survived tissue freezing. At a chilling rate of 0.3 degreesC/min, mean supercooling points (SCP) ranged from -25.9 degrees C in eggs to -16.5 degrees C in unfed females. The SCP of all other stages was significantly higher than that of eggs. Mean SCPs of unfed adult ticks dehydrated to 50% or 75% of their critical water mass were significantly lower than that of fully hydrated ticks. The SCPs of ticks acclimated by several weeks exposure to 0 degrees C or 38 degrees C were significantly lower than those of adult ticks kept constantly at 28 degrees C.en
dc.description.librarianmn2012en
dc.identifier.citationStark, U & Gothe, R 2001, 'Studies on the critical water mass, rehydration capability and potential, acute chill tolerance and supercooling point of Argas (Persicargas) walkerae (Acari: Argasidae)’. Onderstepoort Journal of Veterinary Research, vol. 68, no. 1, pp. 11-20.en
dc.identifier.issn0030-2465
dc.identifier.urihttp://hdl.handle.net/2263/18487
dc.languageen
dc.publisherPublished jointly by the Agricultural Research Council, ARC-Onderstepoort Veterinary Institute and the Faculty of Veterinary Science, University of Pretoria.en
dc.rights© ARC-Onderstepoort and Faculty of Veterinary Science, University of Pretoria (original). © University of Pretoria. Dept of Library Services (digital).en
dc.subjectVeterinary medicineen
dc.subjectArgas walkeraeen
dc.subjectCold-hardinessen
dc.subjectCritical water massen
dc.subjectRehydrationen
dc.subject.lcshVeterinary medicine -- South Africa
dc.subject.lcshTicks -- South Africaen
dc.subject.lcshArgasidae -- South Africaen
dc.titleStudies on the critical water mass, rehydration capability and potential, acute chill tolerance and supercooling point of Argas (Persicargas) walkerae (Acari: Argasidae)en
dc.typeArticleen

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