DOI: 10.5061/dryad.ngf1vhj14
title: Data from: Thermal plasticity in development and diapause strategy in a temperate butterfly across a latitudinal gradient

description: Trade-offs among traits are central to life-history theory and often
 closely linked to an organism’s fitness. Understanding how these
 trade-offs vary among populations and across environments is therefore
 important to more accurately predict species’ responses to future climate
 change. However, the extent to which responses vary across populations
 remains unknown because few studies investigate intraspecific
 differences.  We performed a full-factorial split-brood common
 garden experiment to test how variation in rearing temperature affects
 developmental timing and other traits important for survival during
 diapause in the Glanville fritillary butterfly (Melitaea cinxia).
 Pre-diapause larvae originating from four regions across a latitudinal
 cline across Europe were reared at four temperatures (25, 28, 31, and 34
 °C), and we used a reaction norm approach to test for evidence of genetic
 differentiation and variation in developmental plasticity across regions.
 We found clear signs of genetic differentiation in multiple developmental
 traits, as well as differences in developmental plasticity. Northern
 larvae entered diapause in the fourth instar when the temperatures were
 low, whereas southern larvae did so in the fifth instar. As a result,
 development time is canalized with regards to temperature in northern
 larvae: due to entering diapause one stage earlier, they develop fast even
 in the cold, whereas southern larvae always develop slower, especially at
 low temperatures. As a trade-off, northern larvae have a lower body mass
 when reared at cooler temperatures compared to southern larvae, and they
 show increased plasticity in diapause mass. No clear clinal patterns were
 found in relative fat content. Our results show that trade-offs between
 body size, development time and growth rate can vary within species living
 across environmental clines, possibly as a consequence of natural
 selection to local environmental conditions or other genetic constraints.
 This variation highlights the importance of recognising the
 context-dependency of relationships between important life-history traits
 and their interactions with local environments in predicting species’
 responses to climate change.
description: # Data from: Thermal plasticity in development and diapause strategy in a
 temperate butterfly across a latitudinal gradient (Verspagen et al.,
 Functional Ecology) These datasets contain all data and code used in the
 analyses of this manuscript. ## Description of the data and file structure
 Data files (.csv) are named as
 "NameYear"\_"DataIdentifier".csv Column title
 abbreviations are largely self-explanatory. More specific details for each
 dataset: Verspagen2023\_ClutchData.csv: In this file we record the
 development of the experimental group as a whole every four days. The
 first five columns together form a unique identifier for each experimental
 group. They contain information on the location of origin (Origin), family
 (Female.ID), Clutch (Clutch.ID), Temperature and replicate. The next
 column shows whether the experiment was done in 2020 (Finland, Estonia and
 Spain) or 2022 (Finland2 and Belgium). The Day column identifies which day
 since the second instar (i.e. start of experiment for this experimental
 group) the measurement was done, and the Date column represents the
 calendar date of this day. Mass is the weight in mg of the group and N the
 number of larvae weighed at this time. Mean.individual.mass is calculated
 as Mass/N and represents the mean mass of an individual of this group at
 this timepoint. N was also used for testing survival (not included in this
 paper) as a measure for how many alive larvae were present over time.
 However, in certain cases a larva was missed during weighing on one day
 but found during the next round (i.e. four days later), indicating that it
 was alive also during the earlier timepoint. A corrected value of N is
 found in N.survival. Verspagen2023\_IndividualData.csv: In this file we
 record development of each individual as measured at diapause. The first
 six columns correspond to the first six columns in the ClutchData file and
 together identify the experimental group. The column Diapause.number adds
 a number between 1-15 for each individual in this experimental group.
 Column Fat.diapause indicates if a larva was sacrificed for fat content
 analysis (F) or not, and thus left to diapause (DP). Diapause.date and
 Diapause.mass represent the date and weight (in mg) at diapause.
 Start.date is the date that the clutch molted to the second instar,
 indicating the start of the experiment and is thus the same for all larvae
 in an experimental group. Development.time (days) is calculated by
 subtracting Diapause.date from Start.date. Mean.start.mass correspons to
 Mean.individual.mass in the ClutchData file and is used together with
 development time to calculate growth rate according to the following
 formula: (ln(Diapause.mass) - ln(Start.mass))/Development.time A PCA was
 performed on diapause mass and development time, and the values from PC1
 are present in the column PCA. A threshold value (see methods section) was
 used to assign an individual to instar 4 or 5 (column Diapause.instar).
 Verspagen2023\_FatData.csv: In this file we record fat content and it
 includes only the individuals for which this was measured (i.e. those with
 "F" in the column Fat.diapause in the IndividualData file. The
 first 15 columns of this file are the same as in the IndividualData file.
 In the column Dry.mass we record the weight of the larva (mg) after
 drying, and this mass thus excludes water. Water.content is calculated by
 subtracting the dry mass from the diapause mass. Relative water content is
 the ratio of water that was present in the larvae, and calculated as
 Dry.mass/Water.content. The column Fat.free.mass contains the mass of the
 larvae after drying and extracting of fat. Fat content is calculated by
 subtracting the fat free mass from the dry mass. Relative.fat.content is
 the ratio of fat that was present in the dry larvae and calculated as
 Fat.content/Dry.mass Verspagen2023\_InstarData.csv: In this file we record
 when a clutch transitioned to the following instar. The first six columns
 correspond to those in the other files and together uniquely identify each
 experimental group. Instar.2.date shows when the larvae in one clutch
 transitioned to the second instar, marking the start of the experiment for
 this group. As a rule, we recorded the date that 50% of the clutch
 transitioned, but in practice larvae in one clutch were well-synced and
 thus close to 90% of larvae transitioned on this day. Columns
 Instar.3.date and Instar.4.date and Diapause.date show the dates that at
 least 50% of the experimental group transitioned to either third or fourth
 instar or diapause. For diapause date, this information was taken from the
 IndividualData file. Columns Instar.2 and Instar.3 contain the amount of
 days the experimental group stayed in this instar and is calculated by
 subtracting Instar.2.date from Instar.3.date (Instar.2) and Instar.4.date
 from Instar.3.date (Instar 3). Instar.4 also shows this information but is
 calculated using the individual diapausing dates. An example for
 experimental group Finland2, Female/family 148, Clutch 11, Temperature 25,
 Replicate a: ID Diapause date Date instar 4 Instar.4 (days) Diapause
 instar 5 24.4.22 22.4.22 2 4 6 24.4.22 22.4.22 2 4 7 24.4.22 22.4.22 2 4 4
 24.4.22 22.4.22 2 4 9 24.4.22 22.4.22 2 4 10 24.4.22 22.4.22 2 4 11
 25.4.22 22.4.22 3 4 12 25.4.22 22.4.22 3 4 13 25.4.22 22.4.22 3 4 14
 25.4.22 22.4.22 3 4 15 30.4.22 22.4.22 8 5 8 24.4.22 22.4.22 2 4 Average
 2.833333333 days Larvae that diapause in fourth instar go to diapause
 almost directly after transitioning to the fourth instar, whereas the
 larva that diapauses in fifth inster (ID 15) spends the normal amount of
 time of roughly one week in this instar. This results in an average of
 2.83 days spent in instar 4. ## Code/Software All analysis were performed
 in R by using the script Analysis.R