Insect size responses to climate change vary across elevations according to seasonal timing

Body size declines are a common response to warming via both plasticity and evolution, but variable size responses have been observed for terrestrial ectotherms. We investigate how temperature dependent development and growth rates in ectothermic organisms induce variation in size responses. Leveraging long-term data for six montane grasshopper species spanning 1768 to 3901m, we detect size shifts since ~1960 that depend on elevation and species’ seasonal timing. Size shifts have been concentrated at low elevations, with the early emerging species (those that overwinter as juveniles) increasing in size, while later season species are becoming smaller. Interannual temperature variation accounts for the size shifts. The earliest season species may be able to take advantage of warmer conditions accelerating growth during early spring development, whereas warm temperatures may adversely impact later season species via mechanisms such as increased rates of energy use or thermal stress. Grass..., Specimens and measurements
Grasshoppers were field collected, mostly by sweep netting as part of weekly surveys, in montane or subalpine sites primarily along the 40th N parallel in Boulder County, CO. Historical collections were led by Gordon Alexander, with sampling concentrated in 1958-1960. We conducted resurveys with sampling concentrated in 2006-2015. The specimens used to measure body size are available in the University of Colorado Museum of Natural History.
Body size was measured as femur length, which is the body size metric that can best be compared between museum and recent specimens. Femur length is widely used to indicate body size in grasshoppers and other insects, due to the ease of measurement and its high correlation with body mass. We measured femurs to the nearest one hundred of a millimeter using digital calipers. Femur length was estimated as the average end to end length of both femurs, which were measured twice for most of the specimens. However, a minority of sp..., , # Data from: Insect size responses to climate changes vary across elevations according to seasonal timing

[https://doi.org/10.5061/dryad.wwpzgmst6](https://doi.org/10.5061/dryad.wwpzgmst6)

The repository includes the following files:

AlexanderBodySize_all.csv: grasshopper body size dataset for the Gordon Alexander collection at the University of Colorado Museum of Natural History.

AlexanderBodySize_wClimate.csv: abbreviated grasshopper body size dataset with appended climate data.

HopperData_Sept2019.csv: data from grasshopper phenological surveys from Buckley et al (2021).

Levy_FemaleGradientDataGrasshopper.csv: reproductive data from Levy and Nufio (2014).

NiwotClimateFilled.csv: climate data for study sites.

## Description of the data and file structure

Data are described in the AlexanderBodysizeData_Readme.csv file and below.

AlexanderBodySize_all.csv

| attributeName | attributeLabel | attributeDefinition | storageType | formatString | unit | mi...