Trade‐offs in thermal response: <scp> <i>Schizotetranychus brevisetosus</i> </scp> winter eggs outperform summer eggs at low temperatures

Abstract Maternal physiological conditions influence offspring performance in egg‐diapausing arthropods. However, the adaptive significance of maternal conditions shaping offspring thermal responses during development is not well understood. In the spider mite Schizotetranychus brevisetosus (Acari: Tetranychidae), females oviposit distinct types of eggs in summer and winter on evergreen host leaves ( Quercus glauca L.). To test whether these maternally determined egg types modulate offspring thermal responses, we compared the development and survival between individuals from the two egg types across nine constant temperatures (15–35°C). Developmental rates increased linearly with temperature for all stages. Regression analyses showed that immature individuals from winter eggs had significantly lower developmental threshold temperatures ( t 0 ) and higher thermal constants ( K ) than those from summer eggs during several developmental stages. Notably, protonymphs and deutonymphs from winter eggs developed faster at low temperatures, while those from summer eggs developed faster at high temperatures, indicating a trade‐off in thermal responses. Survival analyses supported this pattern: survival to adulthood was higher in individuals from winter eggs at 15°C, while survival of those from summer eggs was higher at ≥32.5°C. These corresponding trends in development and survival suggest that the maternal environment affects offspring thermal performance. In the field, winter eggs develop during March, when night temperatures fall below 10°C, whereas summer eggs develop when temperatures are high, sometimes exceeding 30°C. Thus, our findings suggest the occurrence of adaptive maternal effects. These effects may help to maintain the long‐term fitness of herbivorous arthropods in seasonally fluctuating environments.