Responses of a widespread pest insect to extreme high temperatures are stage-dependent and divergent among seasonal cohorts

Insect populations in temperate climates can show seasonal differences in demographic rates. Extreme high-temperature events (EHTs) are increasing in frequency across all seasons. These may, in turn, disrupt insects’ season-specific demographic strategies. However, whether insect populations respond to EHTs in a season-specific fashion is not known, but may be critical for forecasting their responses to climate change. We conducted a series of common garden experiments measuring the inherent vital rates of spring, summer, and autumn cohorts of a global nonmigratory pest, the oriental fruit moth (Grapholita molesta), under constant mild temperatures, EHT exposures at different life stages, and short-term heat-hardening followed by EHT exposure at different life stages. We simultaneously conducted a 4-year survey of G. molesta in orchards to link our experimental results to observed population dynamics in the field. We encountered intrinsic variation in vital rates and reproductive traits..., Lab experiment: 
We conducted a common garden experiment to assess whether the three seasonal cohorts had different vital rates under benign climate conditions. For the grand-offsprings of each seasonal cohort, we added 40 newly laid eggs of G. molesta into the calyx cavity of a single apple. This was repeated for at least twenty apples per cohort. We then placed the inoculated apples under a mild climate (25±1°C, RH: 60±10%, and 16 Light: 8 Dark). We randomly photographed and measured the length of over 47 newly laid eggs for each seasonal cohort. After hatching, the young larvae fed inside their apple until they became mature larvae (3rd-4th instar) and then left the apple. We counted the larvae emerging from fruits, then transferred each one to its own small plastic tube (0.6 cm in diameter and 5 cm in length) for pupation. Once adults emerged, we randomly paired newly eclosing adults (male and female) into plastic cups (6 cm in diameter and 8 cm in length) fed with 5% honey-water so..., , # Responses of a widespread pest insect to extreme high temperatures are stage-dependent and divergent among seasonal cohorts

[https://doi.org/10.5061/dryad.x95x69pv6](https://doi.org/10.5061/dryad.x95x69pv6)

## Description of the data and file structure

**Explanation for sheet names of the raw data (raw data.xlsx):**

**Lab experiments:**

\"Adult trait under No EHT\": Adult traits for the individuals of 3 cohorts experiencing no extreme high temperature events.

\"Development time under No EHT\": Development time for the immature individuals of 3 cohorts experiencing no extreme high temperature events.

\"N in lifestage under No EHT\": Numbers of moths in each life stage of 3 cohorts experiencing no extreme high temperature events.

\"Egg_length under No EHT\": Length of eggs of 3 cohorts experiencing no extreme high temperature events.

\"Adult trait under EHT\": Adult traits for the individuals of 3 cohorts experiencing high temperature events appied to different life stages.

\"Immature du...