Molecular adaptations to heat stress in the thermophilic ant genus Cataglyphis

Over the last decade, increasing attention has been paid to the molecular adaptations used by organisms to cope with thermal stress. However, to date, few studies have focused on thermophilic species living in hot, arid climates. In this study, we explored molecular adaptations to heat stress in the thermophilic ant genus Cataglyphis, one of the world's most thermotolerant animal taxa. We compared heat tolerance and gene expression patterns across six Cataglyphis species from distinct phylogenetic groups that live in different habitats and experience different thermal regimes. We found that all six species had high heat tolerance levels with critical thermal maxima (CTmax) ranging from 43celcius to 45celcius and a median lethal temperature (LT50) ranging from 44.5celcius to 46.8celcius. Transcriptome analyses revealed that, although the number of differentially expressed genes varied widely for the six species (from 54 to 1118), many were also shared. Functional annotation of the differentially expressed and co-expressed genes showed that the biological pathways involved in heat-shock responses were similar among species and were associated with four major processes: the regulation of transcriptional machinery and DNA metabolism; the preservation of proteome stability; the elimination of toxic residues; and the maintenance of cellular integrity. Overall, our results suggest that molecular responses to heat stress have been evolutionarily conserved in the ant genus Cataglyphis and that their diversity may help workers withstand temperatures close to their physiological limits.

Automated summary

This study focused on molecular adaptations to heat stress in the thermophilic ant genus Cataglyphis and found that all six species had high heat tolerance levels with similar heat-shock response pathways, involving the regulation of transcriptional machinery, preservation of proteome stability, elimination of toxic residues, and maintenance of cellular integrity. The results suggest that these molecular responses have been evolutionarily conserved in Cataglyphis ants and may help them withstand temperatures close to their physiological limits.