DOI: 10.5061/dryad.80gb5mm39
title: Oviposited eggs are sensitive to experimental heatwaves

description: Extreme, variable heatwaves are predicted to increase in frequency under
 global warming, leading to thermal stress that can be damaging to
 biodiversity. Recently, it has been shown that exposure to heatwaves is
 detrimental for adult insect reproduction, reducing population viability.
 However, relatively little is known about how oviposited insect eggs, one
 of the early stages post-fertilisation, are affected by heatwaves. Here,
 we explore the impact of short- and longer-term thermal stress from
 experimental heatwaves in an economically important insect model, the red
 flour beetle (Tribolium castaneum). We uncovered that even short-term
 exposures (of 2 and 5 hours at 30, 40, 42, 44, 46, 48, and 50 °C) resulted
 in a drastic decline in the survival of oviposited eggs, a trend that was
 also observed when eggs experienced longer durations (1, 3, and 5 days at
 42 °C). Experiments were run independently across two labs, with results
 found to be reproducible, reinforcing confidence in the findings.
 Collectively, our results suggest that oviposited eggs (early embryos) may
 be particularly vulnerable to heatwaves, even when the exposures are
 brief.
description: # Oviposited eggs are sensitive to experimental heatwaves Dataset DOI:
 [10.5061/dryad.80gb5mm39](https://doi.org/10.5061/dryad.80gb5mm39) ##
 Description of the data and file structure ***Oviposited eggs are
 sensitive to experimental heatwaves*** This study investigates the
 consequences of short- and long-term heatwave exposures on oviposited
 insect eggs (*Tribolium castaneum*) and subsequent embryonic survival, as
 well as developmental stage failures were quantified. Overall, from an
 outbred stock population (non-overlapping generations), we set up these
 assays. This work constitutes data files (.csv) and an Rscript file.
 Everyone involved (except MJGG) in the study contributed to data
 collection. Miss. Natasha Brown (research technician) helped with some of
 the pilot study counts, helped curate the material, and ran the assays.
 ### File: UEA_Egg_HW_Results_2025.csv Dataset describing adult counts
 (from lab A) when eggs were exposed to short-term experimental heatwaves
 across temperatures (°C) and durations (hours – h). Fodder quantity (7.5
 grams – g) Column A: Location Lab A, where the assays were conducted
 Column B: Day Day when the experiments were run, levels: 5 (as short-term
 exposures were run across five independent days) Column C: temp
 Experimental heatwave exposure (°C) Column D: duration (hours- h) Duration
 the eggs were exposed, levels: 2 (2 h and 5 h) Column E: count Adults
 counted after the eggs were exposed  Column F: Date Collected Date when
 the heatwaves were run and the offspring counted ###
 Leeds_Egg_HW_Results_2025_sHW.csv Dataset describing adult counts (from
 lab B) when eggs were exposed to short-term experimental heatwaves across
 temperatures (°C) and durations (hours – h). Column A: temp Experimental
 heatwave exposure (°C) Column B: fodder Fodder quantity (7.5 grams – g)
 Column C: duration (hours- h) Duration the eggs were exposed, levels: 2 (2
 h and 5 h) Column D: Rep Individual replicates within each treatment, and
 a random ID given to the samples Column E: Rand.Code A random code was
 used to anonymize all the information, which allowed for control of any
 biases when running the assays Column F: Off.Counts Offspring counts
 Column G: Pupae Dead pupae counts within the batches Column H: Larvae Dead
 larval counts Column I: Treat Short-term heatwave treatment (description
 only) Column J: Day The day that the assays were run (random blocks) in
 Lab B ### Leeds_Egg_HW_Results_2025.csv Dataset describing adult counts
 (from lab B) when eggs were exposed to **long-term experimental
 heatwaves** across temperatures (°C) and durations (hours – h). Fodder:
 7.5 g Column A: ID Replicate sample ID Column B: Temp Experimental
 heatwave exposure (°C) Column C: Days.Exposed Heatwave exposure (in days)
 Column D: Counts Offspring counts (adults that eclosed after eggs were
 exposed) Column E: Life.Stage Life stages that failed during development
 after the fertilised, unhatched oviposited eggs were exposed to long-term
 heatwaves Column F: Notes Nominal data describing the stage (dead or
 alive) Column G: Heatwave Long-term heatwave (descriptive) ###
 Leeds_Egg.Counts.Fodder.csv Dataset describing egg counts (from labs A and
 B) from a subset of samples (in 7.5 g of fodder) from the short-term
 heatwaves, frozen at the time of setting up the assays. These counts were
 done on anonymised batches that were then de-anonymized, and the sample
 IDs were compared once the egg counts were completed for plotting. Column
 A: ID Replicate sample ID Column B: Loc Location where the samples were
 collected from Column C: Fodder.mass (grams – g), without oats, just flour
 + yeast. Mass of the container with the fodder was measured using an
 electronic AND balance to the second decimal point (XX.XX g) Column D:
 Egg.Counts Eggs counted Column E: Larvae Whether at the point of eggs
 being frozen, whether any of the eggs hatched or not. So the presence of
 larvae was checked at the time of the egg counts Column F: Assayed When
 the egg count assays were carried out (day) Column G: Sample.Block Block
 the samples came from (e.g., A-E or Sat and Sun) Column H: Scoop Not
 applicable; cells are empty ### Life_Stage_Deaths_Long_HW_2025.csv Dataset
 describing life stage deaths (from lab B, in 7.5 g of fodder) from the
 short-term heatwaves. Column A: Rep Replicate sample ID Column B: Temp
 (°C) Heatwave temperature (°C) Column C: Fodder (grams – g), Fodder mass
 used Column D: Duration (hours - h) Duration in hours Column E: Offspring
 Total number of offspring counted across replicate pots Column F: Deaths
 Life stages that had died during their development Column G: Prop.Dead
 (number) Proportion dead, life stage – Deaths/Offspring Column H: Stage
 (nominal) Life stage that died Column I: Day (nominal) Day the assays were
 carried out ### Lifestage_failures_LHW_210525.csv Dataset describing life
 stage deaths (from lab B, in 7.5 g of fodder) from the long-term
 heatwaves. Column A: Temp (°C) Heatwave temperature (°C) Column B:
 Duration (days - d) Duration in hours Column C: Off.Counts Total number of
 offspring counted across replicate pots Column D: Deaths Life stages that
 had died during their development Column E: Percent (number) Percentage of
 the life stage that died, calculated as – Deaths/Off.Counts Column F:
 Life.Stage (nominal) Life stage that died Column G: Replicates Replicate
 sample number Column H: Fodder (grams – g), Fodder mass used Column I:
 Type (nominal) Heatwave type ### Lifestage_failures_sHW_210525.csv
 Summarised dataset describing life stage deaths (from lab B, in 7.5 g of
 fodder) from the short-term heatwaves. Column A: Temp (°C) Heatwave
 temperature (°C) Column B: Off.Counts Total number of offspring counted
 across replicate pots Column C: Deaths Life stages that had died during
 their development Column D: Percent (number) Percentage of the life stage
 that died, calculated as – Deaths/Off.Counts Column E: Life.Stage
 (nominal) Life stage that died Column F: Day (nominal) Day the assays were
 run Column G: Duration (hours - h) Duration the heatwaves were run for
 Column H: Replicates Replicate sample number Column I: Fodder (grams – g),
 Fodder mass used Column I: Type (nominal) Heatwave type ###
 Supporting_Information_Fig_1.3_2025.csv Summarised dataset describing
 impacts of short-term heatwaves on oviposited eggs when this was initially
 run as a pilot study. Column A: Blinded_code Temperature treatments (°C)
 that were anonymized using a code Column B: ID Replicate ID for each
 sample Column C: Counts Offspring counts Column D: Duration (hours - h)
 Duration the heatwaves were run for Column E: ForT (grams – g), Fodder
 mass used Column F: Rep Replicate sample number Column G: Counted by User
 who counted the offspring Column H: Species Species ID Column I: Set up
 User for setting up Column J: Expt Experiment ID Column K: Date Not
 applicable ## Code File: RScript_Oviposited_Eggs_Heatwaves.R ***R Session
 Info:*** R version 4.5.0 (2025-04-11) Platform: aarch64-apple-darwin20
 Running under: macOS Sequoia 15.5   Matrix products: default BLAS:  
 /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libBLAS.dylib LAPACK: /Library/Frameworks/R.framework/Versions/4.5-arm64/Resources/lib/libRlapack.dylib;  LAPACK version 3.12.1   locale: \[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8   time zone: Europe/London tzcode source: internal   attached base packages: \[1] stats     graphics  grDevices utils     datasets  methods   base       other attached packages:  [1] ggpubr_0.6.0    lubridate_1.9.4 forcats_1.0.0   stringr_1.5.1   dplyr_1.1.4     purrr_1.0.4     readr_2.1.5     tidyr_1.3.1     [9] tibble_3.2.1    tidyverse_2.0.0 Rmisc_1.5.1     plyr_1.8.9      lattice_0.22-6  ggplot2_3.5.2    loaded via a namespace (and not attached):  [1] gtable_0.3.6       crayon_1.5.3       compiler_4.5.0     ggsignif_0.6.4     tidyselect_1.2.1   Rcpp_1.0.14        [7] scales_1.4.0       R6_2.6.1           labeling_0.4.3     generics_0.1.4     Formula_1.2-5      backports_1.5.0   \[13] car_3.1-3          pillar_1.10.2      RColorBrewer_1.1-3 tzdb_0.5.0         rlang_1.1.6        broom_1.0.8       \[19] stringi_1.8.7      timechange_0.3.0   cli_3.6.5          withr_3.0.2        magrittr_2.0.3     grid_4.5.0        \[25] rstudioapi_0.17.1  hms_1.1.3          lifecycle_1.0.4    vctrs_0.6.5        rstatix_0.7.2      glue_1.8.0        \[31] farver_2.1.2       abind_1.4-8        carData_3.0-5      tools_4.5.0        pkgconfig_2.0.3