Hymenopteran queens are collectively highly fecund, often long-lived individuals that undergo dramatic physiological changes after they mate and establish a nest. However, the degree to which these changes are conserved among species with different life histories is not well-defined. We conducted a comparative proteomic study investigating differences between reproductive stages (virgins, mated, and established queens) of Apis mellifera, Bombus impatiens, B. terrestris, and Lasius niger. We identified conserved upregulation of proteins involved in anatomical and system development as queens transition to establishing a nest in all species except B. terrestris. We also identified conserved patterns of vitellogenin, vitellogenin receptor, and immune responsive protein (IRP)30, all of which are proteins typically associated with oviposition. However, expression patterns of other immune proteins, heat-shock proteins (HSPs), detoxification enzymes, and antioxidant enzymes were more dissimilar, with some species exhibiting similar trends and coregulation through reproductive stages, while others exhibited variable or opposite patterns. These conserved and unique profiles likely in part reflect similarities and differences in selective pressure on reproductive stages of each species and may indicate differing abilities to respond to emergent pathogens or environmental change.

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 phylogenetically distant species that live in different habitats and experience different thermal regimes. We found that all six species had similar heat tolerance levels and critical thermal maxima. Furthermore, the transcriptome analyses revealed that, although the number of differentially expressed genes varied widely for the 6 species (from 54 to 1,118), many were also shared. Functional annotation of the differentially expressed and co-expressed genes then 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 versatility may help workers withstand temperatures close to their physiological limits.