Data from: Extreme heat reduces host and parasite performance in a butterfly-parasite interaction
Data files
Dec 27, 2023 version files 138.94 KB
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HemocyteCounts_June5.csv
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Merozoites_7_21.csv
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mtemp_comp_Nov1_2021.csv
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README.md
Abstract
Environmental temperature fundamentally shapes insect physiology, fitness, and interactions with parasites. Differential climate warming effects on host versus parasite biology could exacerbate or inhibit parasite transmission, with far-reaching implications for pollination services, biocontrol, and human health. Here, we experimentally test how controlled temperatures influence multiple components of host and parasite fitness in monarch butterflies (Danaus plexippus) and their protozoan parasites Ophryocystis elektroscirrha. Using five constant temperature treatments spanning 18-34°C, we measured monarch development, survival, size, immune function, and parasite infection status and intensity. Monarch size and survival declined sharply at 34°C, as did infection probability, suggesting that hot temperatures decrease both host and parasite performance. The lack of infection at 34°C was not due to greater host immunity or faster larval development but could instead reflect the thermal limits of parasite invasion and within-host replication. In the context of ongoing climate change, our experiment suggests that temperature increases above the upper thermal range will reduce the fitness of both monarchs and their parasites, with lower infection rates potentially mitigating the impact of extreme heat on future monarch abundance and distribution.
README: Extreme heat reduces host and parasite performance in a butterfly-parasite interaction
https://doi.org/10.5061/dryad.tht76hf4r
This file contains three datasets describing monarch performance and parasite infection outcomes across a gradient of five constant temperatures along with the code used to perform statistical analysis.
Description of the data and file structure
File: mtemp_comp_Nov1_2021.csv
This file contains a row for each individual monarch "ID," with columns on the temperature treatment, host genetic lineage, and parasite strain used (if inoculated). For each monarch, there are data on key dates in the experiment (e.g. date inoculated, date of death), monarch performance metrics, and infection and intensity measures. Cells for traits that were not measured for an individual contain "NA". This file is used for the majority of analysis, including generalized additive models and generalized linear models of traits across temperature.
File: Hemocyte_counts_June5.csv
This file contains raw hemocyte counts for hemocytomer chambers along with counts of specific immune cell types. Additional columns include the hemocyte concentrations (per microliter of hemolymph), log base 10 transformed concentration, and proportions of each of the four immune cell types. Cells with NA for hemocytes correspond to hemocytometer chambers that were not measureable (most often due to melanization or lipid contamination). A few larvae and pupae were not massed, so their Mass is listed as NA.
File: Merozoites_7_21.csv
This file contains average number of of internal parasite stages (merozoites) per hemocytometer chamber for viable pupal hemolymph samples. Additional columns contain the merozoite concentrations (per microliter of hemolymph) and log base 10 transformed concentration. A few pupae were not massed, so their Mass is listed as NA.
Column names defined:
"ID" = uniquie monarch identification number (1-450)\
"Temp" = Temperature treamtment (18, 22, 26, 30, 34)\
"Lineage" = One of three outbred host lineages (B, D, F)\
"OE_strain" = Parasite treatment (control, E3, or E10)\
"Inoculation" = date fed inoculation leaf (all monarchs were inoculated outside of incubators - except for a few that took >24 hours to consume the inoculum)\
"Into_pint" = date put into an individual pint within the incubator\
"Bleed_stage.x" = assigned stage to be sampled for hemolymph (None, Larva, Pupa)\
"Bleed_date.x" = date hemolymph taken\
"Death_date" = date died (most entries have notes on stage at death)\
"Pupation_date" = date pupated (either as J splitting skin or completed pupa)\
"Eclosion_date" = date adult emerged\
"Surv_pupa" = binary survival to pupal stage (1,0)\
"Surv_adult" = binary survival to adult stage (1,0)\
"Wing_deformity" = score of how deformed wings are (0 = no deformity to 3 = extremely deformed) (made binary with 2 or 3 as deformed for analysis)\
"Adult_death_date" = date of adult death\
"Sex" = Male or female (for all individuals surviving to adulthood)\
"Infection_status" = binary infected or not (1,0)\
"OE_score" = infection intensity from tape samples (0 to 5)\
"Dev_pupa" = time to pupation (days)\
"Dev_adult" = time to adult emergence (days)\
"Adult_longevity" = lifespan as an adult (death - emergence)(days)\
"NOTES" = any notes on individual during experiment\
"Bleed_date.y" = date hemolymph taken (from hemolymph datasheet)\
"Who" = researcher who counted hemocytes\
"Bleed_stage.y" = stage actually sampled for hemolymph (None, Larva, Pupa) (from hemocyte datasheet)\
"Mass" = mass of some larvae and pupa (only for subset of bled individuals) (g, from hemocyte datasheet)\
"AvgHemo" = average number of hemocytes in one chamber of kova hemocytometer slide (from hemocyte datasheet)\
"Hemo_ul" = hemocytes per microliter (AvgHemo*10) (from hemocyte datasheet)\
"LogHemo" = Log base 10 of (Hemo_ul +1) (from hemocyte datasheet)\
"PropPlasm" = proportion of hemocytes that were classified as plasmatocytes (out of first ~100 cells in kova chambers (or all cells in kova chambers if <100) (from hemocyte datasheet)\
"PropOeno" = proportion of hemocytes that were classified as oenocytoids (out of first ~100 cells in kova chambers (or all cells in kova chambers if <100) (from hemocyte datasheet)\
"PropSpher" = proportion of hemocytes that were classified as spheroids (out of first ~100 cells in kova chambers (or all cells in kova chambers if <100)(from hemocyte datasheet)\
"PropGran" = proportion of hemocytes that were classified as granulocytes (out of first ~100 cells in kova chambers (or all cells in kova chambers if <100)(from hemocyte datasheet) "Initials" = researcher who counted vortexing slides for spore load\
"Date" = date sample vortexed for spore load analysis\
"AvgOE_count" = average number of OE spores in one chamber of kova hemocytometer slide\
*"Spore_load" = OE spores per monarch (AvgOE_count*10 (OE per ul) and * 5000 as monarchs were vortexed in 5mL of water)\
"logSpore_load" = Log base 10 of (Spore_load +1)\
"Area" = total wing area in mm^2\
"Length" = Wing length in mm\
"Breadth" = Wing width in mm\
"AspectRatio" = Wing length / breadth (measure of wing elongation - migratory wings typically more elongated) - not used in analysis\
"FinalAbsorbance" = Phenoloxidase assay absorbance value at the final timestep (from BioTek microplate reader software)
Sharing/Access information
Data and code can also be accessed on GitHub:
Resources we found helpful:
Code/Software
Statistical analyses were completed in R (v. 4.0.5). Code was implemented using loaded packages: tidyverse, ggplot2, lme4, visreg, plyr, mgcv, MASS, itsadug, and sjPlot.
File: GAM_temp2019_Jul24_2023.rmd
This R markdown file contains generalized additive model analysis of control monarch performance, performance of infected vs. uninfected monarchs, and infection outcomes. Also contains the linear model assessing whether monarch tolerance to infection varied among temperature treatements.
File: GAM_temp2019_Nov26_2023.rmd\
This R markdown file is an updated version of the above file from July. This version includes analyses on the subset of infected monarchs assessing whether there are parasite strain-specific effects on monarch performance metrics across temperature.
File: GLM_immuneTradeoffs_2019.rmd
This R markdown file contains generalized linear model analysis of tradeoffs between monarch immunity and fitness measures or infection outcomes along with generalized additive models for immune cell proportions across temperature.
File: MonarchOE_Temperature_Infection2019-main.Rproj is the R project that bundles the relevant scripts and data files used for the analysis. Save project file in the same folder as markdown files and a folder named "data" the holds the three .csv files. Open the project in R Studio and then access the markdown files within the project.
Methods
We used a constant temperature experiment to explore how temperature influences components of host and parasite performance in monarch butterflies (Danaus plexippus) and their protozoan parasite OE (Ophryocystis elektroscirrha). In lab incubators, we used five constant temperature treatments spanning 18-34°C to measure monarch development, survival, size, immune function, and OE infection status and intensity.
Data was entered using Excel and analyzed in R Studio.
Usage notes
R and R Studio are required to open the data files included.