dc.contributor.author |
Gothe, R.
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dc.contributor.author |
Stark, Ulrike
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dc.contributor.editor |
Boomker, Jacob Diederik Frederik |
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dc.date.accessioned |
2012-03-20T13:08:29Z |
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dc.date.available |
2012-03-20T13:08:29Z |
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dc.date.created |
2012 |
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dc.date.issued |
2001 |
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dc.description |
The 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. |
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dc.description.abstract |
The 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.librarian |
mn2012 |
en |
dc.identifier.citation |
Stark, 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. |
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dc.identifier.issn |
0030-2465 |
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dc.identifier.uri |
http://hdl.handle.net/2263/18487 |
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dc.language |
en |
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dc.publisher |
Published jointly by the Agricultural Research Council, ARC-Onderstepoort Veterinary Institute and the Faculty of Veterinary Science, University of Pretoria. |
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dc.rights |
© ARC-Onderstepoort and Faculty of Veterinary Science, University of Pretoria (original).
© University of Pretoria. Dept of Library Services (digital). |
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dc.subject |
Veterinary medicine |
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dc.subject |
Argas walkerae |
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dc.subject |
Cold-hardiness |
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dc.subject |
Critical water mass |
en |
dc.subject |
Rehydration |
en |
dc.subject.lcsh |
Veterinary medicine -- South Africa |
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dc.subject.lcsh |
Ticks -- South Africa |
en |
dc.subject.lcsh |
Argasidae -- South Africa |
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dc.title |
Studies on the critical water mass, rehydration capability and potential, acute chill tolerance and supercooling point of Argas (Persicargas) walkerae (Acari: Argasidae) |
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dc.type |
Article |
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