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Deleterious effects of repeated cold exposure in a freeze-tolerant sub-Antarctic caterpillar.

https://arctichealth.org/en/permalink/ahliterature95808
Source
J Exp Biol. 2005 Mar;208(Pt 5):869-79
Publication Type
Article
Date
Mar-2005
Author
Sinclair Brent J
Chown Steven L
Author Affiliation
Spatial, Physiological and Conservation Ecology Group, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa. celatoblatta@yahoo.co.uk
Source
J Exp Biol. 2005 Mar;208(Pt 5):869-79
Date
Mar-2005
Language
English
Publication Type
Article
Keywords
Acclimatization - physiology
Analysis of Variance
Animals
Body Composition
Body Weight
Climate
Crystallization
Digestive System - pathology
Feeding Behavior - physiology
Freezing
Indian Ocean Islands
Larva - physiology
Moths - physiology
Abstract
Multiple freeze-thaw cycles are common in alpine, polar and temperate habitats. We investigated the effects of five consecutive cycles of approx. -5 degrees C on the freeze-tolerant larvae of Pringleophaga marioni Viette (Lepidoptera: Tineidae) on sub-Antarctic Marion Island. The likelihood of freezing was positively correlated with body mass, and decreased from 70% of caterpillars that froze on initial exposure to 55% of caterpillars that froze on subsequent exposures; however, caterpillars retained their freeze tolerance and did not appear to switch to a freeze-avoiding strategy. Apart from an increase in gut water, there was no difference in body composition of caterpillars frozen 0 to 5 times, suggesting that the observed effects were not due to freezing, but rather to exposure to cold per se. Repeated cold exposure did not result in mortality, but led to decreased mass, largely accounted for by a decreased gut mass caused by cessation of feeding by caterpillars. Treatment caterpillars had fragile guts with increased lipid content, suggesting damage to the gut epithelium. These effects persisted for 5 days after the final exposure to cold, and after 30 days, treatment caterpillars had regained their pre-exposure mass, whereas their control counterparts had significantly gained mass. We show that repeated cold exposure does occur in the field, and suggest that this may be responsible for the long life cycle in P. marioni. Although mean temperatures are increasing on Marion Island, several climate change scenarios predict an increase in exposures to sub-zero temperatures, which would result in an increased generation time for P. marioni. Coupled with increased predation from introduced house mice on Marion Island, this could have severe consequences for the P. marioni population.
PubMed ID
15755885 View in PubMed
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The effects of acclimation on thermal tolerance, desiccation resistance and metabolic rate in Chirodica chalcoptera (Coleoptera: Chrysomelidae).

https://arctichealth.org/en/permalink/ahliterature95789
Source
J Insect Physiol. 2005 Sep;51(9):1013-23
Publication Type
Article
Date
Sep-2005
Author
Terblanche John S
Sinclair Brent J
Jaco Klok C.
McFarlane Mhairi L
Chown Steven L
Author Affiliation
Spatial, Physiological, and Conservation Ecology Group, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa. jst@sun.ac.za
Source
J Insect Physiol. 2005 Sep;51(9):1013-23
Date
Sep-2005
Language
English
Publication Type
Article
Keywords
Acclimatization - physiology
Animals
Beetles - metabolism
Body Weight
Cold Temperature
Desiccation
Energy Metabolism
Water Deprivation - physiology
Abstract
Despite much focus on species responses to environmental variation through space and time, many higher taxa and geographic areas remain poorly studied. We report the effects of temperature acclimation on thermal tolerance, desiccation rate and metabolic rate for adult Chirodica chalcoptera (Coleoptera: Chrysomelidae) collected from Protea nerifolia inflorescences in the Fynbos Biome in South Africa. After 7 days of acclimation at 12, 19 and 25 degrees C, critical thermal maxima (mean+/-s.e.: 41.8+/-0.2 degrees C in field-fresh beetles) showed less response (
PubMed ID
15955537 View in PubMed
Less detail