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No trade-off between high and low temperature tolerance in a winter acclimatized Danish Drosophila subobscura population

Sørensen, Jesper Givskov; Kristensen, Torsten Nygaard; Loeschcke, Volker and Schou, Mads Fristrup LU (2015) In Journal of Insect Physiology 77. p.9-14
Abstract
Coping with cold winter conditions is a major challenge for many insects.

In early spring we observed newly emerged Drosophila subobscura, which had overwintered as larvae and pupae. As temperatures increase during spring these flies are faced with higher minimum and maximum temperatures in their natural microhabitat. Thus, there is a potential costly mismatch between winter and early spring acclimatization and the increased ambient temperatures later in adult life.

We obtained individuals from a natural Danish population of D. subobscura and acclimated them in the laboratory to 20 °C for one generation, and compared critical thermal maximum (CTmax) and minimum (CTmin) to that of individuals collected directly from their... (More)
Coping with cold winter conditions is a major challenge for many insects.

In early spring we observed newly emerged Drosophila subobscura, which had overwintered as larvae and pupae. As temperatures increase during spring these flies are faced with higher minimum and maximum temperatures in their natural microhabitat. Thus, there is a potential costly mismatch between winter and early spring acclimatization and the increased ambient temperatures later in adult life.

We obtained individuals from a natural Danish population of D. subobscura and acclimated them in the laboratory to 20 °C for one generation, and compared critical thermal maximum (CTmax) and minimum (CTmin) to that of individuals collected directly from their natural microhabitat. The two populations (laboratory and field) were subsequently both held in the laboratory at 20 °C and tested for their CTmax and CTmin every third day for 28 days.

At the first day of testing, field acclimatized D. subobscura had both higher heat and cold resistance compared to laboratory flies, and thereby a considerable larger thermal scope. Following transfer to the laboratory, cold and heat resistance of the field flies decreased over time relative to the laboratory flies. Despite the substantial decrease in thermal tolerances the thermal scope remained larger for field acclimatized individuals for the duration of the experiment.

We conclude that flies acclimatized to their natural microhabitat had increased cold resistance, without a loss in heat tolerance. Thus while a negative correlation between cold and heat tolerance is typically observed in laboratory studies in Drosophila sp., this was not observed for field acclimatized D. subobscura in this study. We suggest that this is an adaptation to juvenile overwintering in temperate cold environments, where developmental (winter) temperatures can be much lower than temperatures experienced by reproducing adults after emergence (spring). The ability to gain cold tolerance through acclimatization without a parallel loss of heat tolerance affects thermal scope and suggests that high and low thermal tolerance act through mechanisms with different dynamics and reversibility. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Cold adaptation, Critical thermal limits, Fluctuating temperatures, Overwintering, Reversibility of acclimation, Thermal scope
in
Journal of Insect Physiology
volume
77
pages
6 pages
publisher
Elsevier Ltd
external identifiers
  • scopus:84927612257
ISSN
1879-1611
DOI
10.1016/j.jinsphys.2015.03.014
language
English
LU publication?
no
id
1e690cac-6c16-436f-b778-8f6b8701bb70
date added to LUP
2017-12-18 09:47:02
date last changed
2018-01-12 11:49:44
@article{1e690cac-6c16-436f-b778-8f6b8701bb70,
  abstract     = {Coping with cold winter conditions is a major challenge for many insects.<br/><br/>In early spring we observed newly emerged Drosophila subobscura, which had overwintered as larvae and pupae. As temperatures increase during spring these flies are faced with higher minimum and maximum temperatures in their natural microhabitat. Thus, there is a potential costly mismatch between winter and early spring acclimatization and the increased ambient temperatures later in adult life.<br/><br/>We obtained individuals from a natural Danish population of D. subobscura and acclimated them in the laboratory to 20 °C for one generation, and compared critical thermal maximum (CTmax) and minimum (CTmin) to that of individuals collected directly from their natural microhabitat. The two populations (laboratory and field) were subsequently both held in the laboratory at 20 °C and tested for their CTmax and CTmin every third day for 28 days.<br/><br/>At the first day of testing, field acclimatized D. subobscura had both higher heat and cold resistance compared to laboratory flies, and thereby a considerable larger thermal scope. Following transfer to the laboratory, cold and heat resistance of the field flies decreased over time relative to the laboratory flies. Despite the substantial decrease in thermal tolerances the thermal scope remained larger for field acclimatized individuals for the duration of the experiment.<br/><br/>We conclude that flies acclimatized to their natural microhabitat had increased cold resistance, without a loss in heat tolerance. Thus while a negative correlation between cold and heat tolerance is typically observed in laboratory studies in Drosophila sp., this was not observed for field acclimatized D. subobscura in this study. We suggest that this is an adaptation to juvenile overwintering in temperate cold environments, where developmental (winter) temperatures can be much lower than temperatures experienced by reproducing adults after emergence (spring). The ability to gain cold tolerance through acclimatization without a parallel loss of heat tolerance affects thermal scope and suggests that high and low thermal tolerance act through mechanisms with different dynamics and reversibility.},
  author       = {Sørensen, Jesper Givskov and Kristensen, Torsten Nygaard and Loeschcke, Volker and Schou, Mads Fristrup},
  issn         = {1879-1611},
  keyword      = {Cold adaptation,Critical thermal limits,Fluctuating temperatures,Overwintering,Reversibility of acclimation,Thermal scope},
  language     = {eng},
  pages        = {9--14},
  publisher    = {Elsevier Ltd},
  series       = {Journal of Insect Physiology},
  title        = {No trade-off between high and low temperature tolerance in a winter acclimatized Danish Drosophila subobscura population},
  url          = {http://dx.doi.org/10.1016/j.jinsphys.2015.03.014},
  volume       = {77},
  year         = {2015},
}