DOI: 10.5061/dryad.kd51c5b7m
title: Longer and warmer prewinter periods reduce post-winter fitness in a diapausing insect

description: 1. Diapause is considered an important adaptation for survival of winter;
 however, insects often enter diapause long before its onset. Thus,
 diapausing insects must also be able to survive these prewinter conditions
 which warm temperatures could make quite energetically taxing despite
 relative inactivity. 2. We tested for both immediate and delayed fitness
 effects of prewinter conditions in diapausing Pieris napi butterfly pupae,
 experimentally exposing them to different prewinter treatments in a
 factorial design. We placed diapausing pupae at one of three temperatures
 (15, 20, 25 °C) for 1 to 16 weeks, followed by the same standardized
 winter for all individuals. 3. We monitored survival at multiple points
 during the experiment, including after winter, as well as their change in
 mass. For a subset of individuals, we also made repeated metabolic
 measurements. 4. We found substantial weight loss during prewinter warm
 periods, greater during longer prewinter treatments at higher
 temperatures. This weight loss was associated with elevated metabolic
 rates at higher temperatures which increased over the duration of the
 prewinter treatment. 5. Although we found little prewinter mortality
 associated with these conditions, mortality was much greater post-winter
 for individuals in long, warm prewinter treatments and the dry mass of
 adults that did survive these conditions was lower, highlighting the need
 to understand chronic or delayed effects of stress on fitness. 6.
 Ultimately, we found substantial fitness consequences of prewinter
 conditions for a diapausing insect. Given that climate change will make
 these prewinter periods both longer and more intense, it will be important
 to understand how dormant organisms tolerate or reduce the length of these
 dormant, inactive periods.
description: The main data set also contains information from two additional
 groups, a second population of Pieris napi from Stockholm and Pieris rapae
 from Kronängen (the same site as the studied Pieris napi population);
 however, larval rearing of these populations went very poorly so initial
 sample sizes were much smaller and extremely few individuals survived the
 experiment. Thus, data from these other groups have not been
 analyzed. As a side effect of how random, balanced
 assignment of pupae to treatments was performed, there are also a
 substantial number of blank cells associated with ID numbers to which a
 pupa was never actually assigned. These can be removed before
 analysis. See methods in associated paper for more
 details.
description: See readme files for more information about each file. .exp files
 from Sable Systems expdata can be made available upon request.
 <strong>PrewinterDiapauseIndividual</strong> Main data file with survival and mass change data from the full experiment <strong>PrewinterDiapauseMetabolismMeasurements</strong> File with data from the repeated metabolism measurements on a subset of treatments in the main experiment. Available as both .xlsx and .csv <strong>PrewinterDiapauseManuScript</strong> R script for producing the statistics and figures from the manuscript.