Regional- and generation-specific phenological shifts of Scirpophaga incertulas (Lepidoptera: Crambidae) in China under climate warming

To assess how climate warming affects the phenology and occurrence patterns of Scirpophaga incertulas, historical phenological records and corresponding temperature data were analyzed using linear regression and Pearson correlation to detect interannual trends and associations with temperature. Results indicated that climate warming has produced significant, region- and generation-specific shifts in the phenology of S. incertulas across Southern, Eastern, and Southwestern China. Results derived from simple linear regression analysis indicated that Southern China showed interannual delays in population peaks across generations, but analyses against rising mean annual temperature indicated peak adult emergence advancement; Pearson correlations revealed strong negative associations with spring, autumn, winter, and annual temperatures. Eastern China exhibited generally earlier first occurrences and overall advancement of population peaks, although some later generations showed delayed first-occurrence dates; phenology correlated negatively with seasonal and annual temperatures. Southwestern China displayed mixed responses: interannual trends included delayed first-generation occurrence and delayed all population peaks, and advanced end occurrence, while temperature-based analyses showed generally earlier first occurrences, a delayed first-generation peak but an advanced second-generation peak and all first occurrence and end occurrence, and a combination of positive and negative temperature correlations. These findings improve understanding of likely occurrence dynamics under future warming and can inform optimization of integrated pest-management timing and strategies.