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The effect of rapid cold hardening on ion homeostasis, mortality,chill-coma recovery and sexual behaviour of Locusta migratoria.

Activity: Talk or presentation typesLecture and oral contribution

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Johannes Overgaard - Lecturer

  • Department of Biological Sciences, Zoophysiology

The effect of rapid cold hardening on ion homeostasis, mortality, chill-coma recovery and sexual behaviour of Locusta migratoria

Sofia Calderon1 and Johannes Overgaard1

 

1 Department of Zoo-physiology, University of Aarhus, Aarhus, Denmark

 

The rapid cold hardening (RCH) response is a naturally occurring phenomenon in insects that

is thought to be responsible for increased cold tolerance during diurnal variations in

temperature. While the benefits of RCH are well established, the underlying physiological mechanisms still remain unresolved. Chill sensitivity in insects has often been related to the inability to maintain ion homeostasis which impairs nervous and muscle function. In the present study we investigated the relationship between RCH, ion homeostasis and cold performance in the migratory locust Locusta migratoria. We found that a 2 hour RCH exposure to 0ºC increased survival after a subsequent exposure to cold shock (2h at -6ºC). RCH also benefitted chill coma recovery and reproductive behaviour after milder cold shocks (2h at -4ºC) demonstrating an important ecological role of RCH for insects experiencing large natural diurnal temperature variations. Both RCH and cold shock altered intra and extracellular distribution of potassium. The RCH treatment alone caused an increase in extracellular [K+] but this treatment also seemed to reduce the ionic disturbance after a subsequent cold shock since the cumulative effect of RCH and cold shock was similar to that of cold shock alone. Further evidence of this was found in the faster recovery of ion homeostasis in RCH treated animals following a cold shock. Although the cause of improved ion homeostasis following RCH is still unresolved, these results points to either reduced membrane permeability or increased ion pump activity as key elements of the RCH response in insects.

7 Dec 2008

Event (Conference)

TitleANZSCPB, 25<sup>th</sup> Anniversary general meeting
Date07/12/200807/12/2008
CitySydney
Country/TerritoryAustralia

ID: 15027112