Impact of varying altitudes and ice-nucleating active bacteria on cold resistance of evergestis extimalis (Lepidoptera: Pyralidae)

To investigate the influence of altitude and exposure to ice nucleating active bacteria (INA) on the cold tolerance of Evergestis extimalis in a high plateau environment, we employed simulated field methods to analyze variations in the super-cooling point (SCP) and freezing point (FP) of E. extimalis. Furthermore, we assessed the impact of INA on cold resistance and the expression of trehalose-6-phosphate synthase (TPS) genes. Our findings indicate that the SCPs of E. extimalis decreased progressively with increasing altitude, with variations in SCP and FP correlating with local environmental temperatures. Notably, exposure to INA bacteria resulted in an increase in SCPs and mortality, while upregulation of TPS genes in response to INA exposure may contribute to the cold resistance of E. extimalis. Overall, our results demonstrate that both altitude and INA bacteria significantly influence the cold resistance and TPS expression of E. extimalis.