Heat shock proteins expression during thermal risk exposure in the temperate xerothermic ant Formica cinerea

Abstract

The abiotic conditions of the desert habitat fluctuate in a circadian rhythm of hot days and cold nights. Species living in desert habitats evolved many adaptations to increase their chances of survival. However, abiotic conditions in xerothermic habitats of a temperate climate are much different. Diurnal fluctuations are not as strong, but animals have to cope with seasonal changes and hibernate during the winter, which may potentially influence their adaptations to critical temperature conditions. We attempted to assess heat resistance adaptations using the example of a widely distributed xerothermic ant Formica cinerea. Using Real-Time PCR, we measured the expression of three heat shock protein genes (Hsp60, Hsp75, Hsp90) and assessed the adaptations of F. cinerea to enable foraging in risk prone conditions. The analysis of gene expression using the Generalized Linear Model surprisingly indicated that there was no significant effect of temperature when comparing workers from the control (23ºC) with workers foraging on the surface of hot sand (47-54ºC). As a next step we tried to estimate the threshold of a thermal resistance with the use of thermal chambers. Expression of all Hsps genes increase compare to the control group, expression of Hsp60 and Hsp90 continued up to 45ºC.