The influence of developmental stage on cold shock resistance and ability to cold-harden in Drosophila melanogaster

• Published in: Journal of insect physiology Vol. 53; no. 2; pp. 179 - 186
• Main Authors: Jensen, Dorthe, Overgaard, Johannes, Sørensen, Jesper G.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.02.2007
• Subjects: Adaptation, Physiological - physiology; Analysis of Variance; Animals; cold stress; Cold Temperature; cold tolerance; developmental stages; Drosophila melanogaster; Drosophila melanogaster - growth & development; Egg; Female; gender differences; Larvae; Life Cycle Stages - physiology; Male; mortality; Pupae; Rapid cold-hardening; Sex Factors; Survival Analysis; temperature; Thermal stress resistance; Time Factors; Larvae; Pupae; Thermal stress resistance; Egg; Rapid cold-hardening
• ISSN: 0022-1910; 1879-1611
• DOI: 10.1016/j.jinsphys.2006.11.008

Thermal sensitivity and ability to rapidly cold- and heat-harden may change during ontogeny. This study reports how inherent cold tolerance and ability to rapidly cold-harden change across eight developmental stages in both genders of Drosophila melanogaster using a similar experimental approach for all stages. Inherent cold tolerance was estimated as LT 50 by assaying cold shock survival over a wide range of temperatures ( - 16 to 5 ∘ C ) . Rapid cold-hardening (RCH) was applied by cooling from 25 to 0 ∘ C at - 0.25 ∘ C min - 1 followed by 1 h at 0 ∘ C . Individuals were cold shocked either directly or after RCH to estimate the effect of RCH. We found large variation in cold tolerance among developmental stages and minor differences between genders. Eggs were most tolerant followed by adults, pupae and larvae. In the light of this and other studies it is suggested that there is a general pattern of stage specific thermal stress resistance in Drosophila. The capacity to rapidly cold-harden was found in both sexes of larval, pupal and adult stages, though some developmental stages showed negative or neutral effects of RCH which was probably due to the cost associated with the hardening treatment in these cold susceptible stages. The early presence of RCH indicates that the mechanisms behind hardening are not stage specific and that RCH may be an ecologically important trait in early stages of ontogeny.