Molecular characterization and seasonal, sex-associated expression patterns of HSP genes in Eurygaster integriceps (Hemiptera: Scutelleridae).

Seasonal environmental variation may be associated with heat-shock protein (HSP) transcription in insects with annual diapause cycles. The Sunn pest, Eurygaster integriceps (Puton), occupies contrasting field and shelter habitats across its univoltine life cycle. We combined transcriptome-guided annotation, motif and conserved-domain analysis, localization prediction, fragment-based structural modeling, phylogenetic placement, and RT-qPCR to characterize partial Hsp60, Hsp70, and Hsp90 sequences and compare their whole-body transcript abundance among 4 field-sampled groups and between sexes. The translated fragments contained family-associated motifs and conserved-domain matches, showed high similarity to hemipteran homologs, and clustered with corresponding Halyomorpha halys Stål sequences, supporting provisional annotation of the 3 partial transcripts. Expression patterns differed among genes. Hsp70 abundance was higher in the summer-sampled group than in the other sampling groups across sexes, whereas Hsp90 showed a sex-dependent pattern, with higher abundance in summer-, autumn-, and winter-sampled males than in spring-sampled males and lower abundance in winter-sampled females than in spring-sampled females. Hsp60 also showed a sex-by-sampling-group pattern, but within-sex comparisons with the spring group were not supported after multiple-comparison adjustment. Because sampling phase covaried with habitat, altitude, cohort, and physiological context, these results describe associations among field-collected groups rather than isolated effects of season or diapause. The study supports provisional sequence-based annotations and identifies gene- and sex-associated transcript patterns that can guide controlled, tissue-resolved investigations of HSP regulation in E. integriceps.