• Acclimation;
  • developmental plasticity;
  • heat shock protein;
  • Lycaena tityrus;
  • rapid hardening;
  • thermal stress

The temporal dynamics of heat shock protein 70 (HSP70) expression in response to longer-term acclimation and rapid hardening in the butterfly Lycaena tityrus is investigated. After a 1-h exposure to 1 °C or 37 °C, HSP70 is quickly up-regulated within 1 h and down-regulated within 2 h. The fast dynamic of HSP70 expression is in contrast to the patterns found in organisms inhabiting more stable thermal environments, and is interpreted as an adaptation to the large and rapid temperature variation experienced by flying ectotherms. HSP70 expression is higher in males than in females, as well as in animals reared at 27 °C than at 20 °C, although it is very similar across the high and low induction temperatures. Animals reared at the higher temperature, however, respond less strongly to high-temperature stress.