DOI: 10.5061/dryad.5mkkwh7fx
title: Climate change impacts on diapause outcomes in Bombus terrestris across an environmental gradient

description: Most temperate insects survive winter by entering a period of dormancy
 called diapause. Some of the greatest climate change impacts are likely to
 occur during this period, as entire populations are represented by a
 relatively small number of hibernating individuals. Bumblebee populations
 are particularly vulnerable because only queens overwinter and any decline
 in the winter survival of queens, or reduced post-diapause fitness, could
 have significant consequences on population dynamics the following spring.
 This study investigated the impact of different overwintering conditions
 on Bombus terrestris queens across an altitudinal gradient in the German
 Alps. Snow pack coverage was manipulated to simulate advanced snow melt
 and delayed snow melt, and maintained for current/control conditions. We
 found that changes in snow pack and altitude affect the level and
 variability of soil temperature across the winter season, but that these
 have no effect on hibernation survival (very high in all cases) or
 subsequent colony establishment (very low in all cases). However,
 altitudinal level did affect weight loss during diapause, with bumblebees
 hibernating at lower levels, and so exposed to higher and more widely
 fluctuating temperatures, losing significantly more weight. Our results
 therefore confirm the potential for negative physiological impacts of
 exposure to higher and more variable winter temperatures during diapause,
 as is increasingly common under climate change. But we also find that
 bumblebees have some resilience to these effects, at least in terms of
 hibernation survival, within the range experienced in our experiments. We
 conclude that further field studies targeted at the range of conditions
 likely to be experienced by European insects over winter are necessary to
 anticipate potential population impacts, but that existing levels of
 climate change are likely sufficient to affect many of these insects, even
 if at sub-lethal levels.
description: # Climate change impacts on diapause outcomes in Bombus terrestris across
 an environmental gradient
 [https://doi.org/10.5061/dryad.5mkkwh7fx](https://doi.org/10.5061/dryad.5mkkwh7fx) ## Description of the data and file structure These data are from a study investigating the impact of different overwintering conditions on *Bombus terrestris* queens across an altitudinal gradient in the German Alps. ### Files and variables #### File: All\_bee\_data\_both\_winters.csv **Description:** Data collected from hibernating bumblebee queens ##### Variables * Winter: Refers to the year experiment carried out. Either 20/21 or 21/22. * Queen colony: The ID of the original colony that the queen came from. * ID: Unique bumblebee ID. * Altitude: The altitude that the queen hibernated at - either low (700 metres above sea level (m.a.s.l.)), mid (1200 m.a.s.l.) or top (1650 m.a.s.l.). * Snow: Snow manipulation treatment - either delayed (additional snow added), advanced (snow removed) or control (snow left at ambient conditions). * Weight_before: Weight of queen before hibernation (g). * Weight_after: Weight of queen after hibernation (g). * Survived: Whether the queen survived hibernation or not (1 for survived, 0 for did not survive). * Foundation: Whether the queen reared at least one offspring to adulthood (1 for yes, 0 for no). * Missing data: NA #### File: Winter\_temps\_all.csv **Description:** Soil temperatures at each treatment site, as recorded by a HOBO datalogger. ##### Variables * Date: Self explanatory. * Day: Numbered from the day the experiment began. * Time: Self explanatory. * Low_advanced: Soil temperature at the low altitude, snow removed treatment site (degree Celsius (°C)). * Low_control: Soil temperature at the low altitude, snow left as ambient treatment site (°C). * Low_delayed: Soil temperature at the low altitude, snow added treatment site (°C). * Mid_advanced: Soil temperature at the mid altitude, snow removed treatment site (°C). * Mid_control: Soil temperature at the mid altitude, snow left as ambient treatment site (°C). * Mid_delayed: Soil temperature at the mid altitude, snow added treatment site (°C). * Top_advanced: Soil temperature at the top altitude, snow removed treatment site (°C). * Top_control: Soil temperature at the top altitude, snow left as ambient treatment site (°C). * Top_delayed: Soil temperature at the top altitude, snow added treatment site (°C).