Data from: Prior heat waves improve survival of field but not domesticated populations of tobacco hornworm exposed to repeated bacterial infections

Malinski, Katherine 1 ; Willett, Chris1; Kingsolver, Joel1

Published Jan 20, 2025 on Dryad. https://doi.org/10.5061/dryad.pvmcvdnv9

Data files

Jan 20, 2025 version files 186.11 KB

bledLarvae_from_prime.csv

363 B
finFieldimmunepriming_HS_datasheet_cleaned2023data.csv

163 KB
README.md
22.76 KB

Abstract

In insects and other invertebrates, prior pathogen exposures can improve immune responses and survival to subsequent infections through immune priming. Alternatively, stress and metabolic costs of multiple infections can impair host immunity and survival. The impact of high temperature extremes on host-pathogen interactions are not well-understood despite the increasing occurrence of heat waves caused by climate change.

The response of insects to heat waves and pathogens depends on recent evolutionary history with selective pressures. Domestication of insect pests has occurred in lab colonies of model species, reducing selective pressures for immune and heat stress responses. Lab strains are often used in immunological or heat stress experiments to represent wild field strains, but the efficacy of this approach is seldom evaluated.

Using the tobacco hornworm (Manduca sexta), we tested the impact of a heat wave during initial pathogen exposure on survival of a secondary infection with Bacillus thuringiensis bacteria. We used a domesticated lab population and a naturally-occurring field population of M. sexta to evaluate impacts of recent domestication on immune and thermal responses.

A heat wave during initial infection significantly increased survival of the secondary B. thuringiensis infection in the field, but not the lab population of M. sexta.

In the field population, survival of the repeated infection was temperature-dependent: exposure to an initial infection event reduced survival of the secondary infection at the control temperature regime, consistent with a stress effect. However, a heat wave during the initial infection event increased survival of the secondary infection, consistent with immune priming effects.

The results of this study demonstrate that a) insect response to thermal stress and pathogens can depend on recent domestication, and b) responses of hosts to repeat pathogen exposures can be temperature-dependent, suggesting that cross-talk between the heat stress and immune memory pathways may have important consequences for host-pathogen outcomes under heat wave events.

README: Data from: Prior heat waves improve survival of field but not domesticated populations of tobacco hornworm exposed to repeated bacterial infections

https://doi.org/10.5061/dryad.pvmcvdnv9

Primary dataset (finFieldimmunepriming_HS_datasheet_2023data.csv) contains data collected from the immune priming experiment run in lab and field M. sexta with initial low dose exposure and subsequent high dose of Bacillus thuringiensis, testing the impact of heat wave during the initial exposure on survival following secondary infection. Data collected summer 2023.

Description of the data and file structure

FE_primecleanedcode.Rmd is the code used to conduct analyses and generate figures (in R). It uses both .csv files included. The primary datasheet (finFieldimmunepriming_HS_datasheet_2023data.csv) is used for all analyses and figures used in the manuscript. The second datasheet (bledLarvae_from_prime.csv) contains data used in the supplementary material.

finFieldimmunepriming_HS_datasheet_2023data.csv is the primary data file for this paper. It contains growth and development data, survival data, and data for the timing of experimental injections and experimental heat wave exposure. Below is a readme for the columns in the data sheet:

column	unit	description
sample.ID	numeric	unique sample identification number used to distinguish samples throughout the experiment
block	categorical	experimental block the samples were run under. Not applicable for this experiment, as all samples were run in the same block
expt_part	categorical	experiment part the samples belonged to (similar to block). Not applicable for this experiment, as all samples were from the same experiment part (i.e. used the same dosages of infections)
trt.group	categorical	treatment group (factorial) the sample was assigned to. combination of prime, temperature, and challenge.
origin	categorical	population the sample originated from. Lab or field
prime	categorical	initial infection treatment the sample received. Bt=low dose Bacillus thuringiensis injection in 10uL volume; n=sham injection of sterile PBS in 10uL volume; na=unmanipulated control (no injection).
temp	categorical	temperature treatment regime the insect was assigned starting at 1st day of fourth instar. Lasted 3 days. HW=heat wave of 32 degrees C +/-10; noHW=25 degrees C+/-10
challenge	categorical	immune challenge during secondary infection treatment the sample received. Bt=Bacillus thuringiensis high dose infection in 25uL volume; N=sham injection with sterile PBS in 25uL volume; NA=unmanipulated control (no injection)
date.PMD	date	date of premature death (premature is defined as death prior to the 5th instar). If NA, data are not applicable (i.e., the sample did not die before 5th instar).
stage.PMD	categorical	life stage at premature death. indicates day of initial infection ('prime' treatment), day after, etc.
date.died	date	date of death after 5th instar. if NA, data are not applicable (i.e., the sample either died prematurely or survived to wandering)
col.stage	categorical	collection stage for field M. sexta. Typically they were collected in the field as eggs, but sometimes 1st or 2nd instar larvae. All lab M. sexta were collected as eggs.
species	categorical	species collected in the field. Manduca quinquemaculata is identical to M. sexta until 3rd instar, so were sometimes found in the experiment accidentally. We ran the experiment with them included, and kept note of the species here. In the Rmd file, we remove them from analyses as we did not have enough to be statistically significant
date.hatch	date	date the insect hatched. NA means not applicable (if the insect was collected after hatching, or exact hatch date was not observed)
date.4th	date	date of molt to 4th instar
mass.4th	numeric (mg)	mass on the day of molt to 4th instar. NA is not available (mass was missed for this sample on this day)
date.5th	date	date of molt to 5th instar. NA is not applicable (insect did not survive to 5th instar)
mass.5th	numeric (mg)	mass on the day of molt to 5th instar. NA is not available if there is a date in date.5th (mass was missed for this sample on this day). If no date in date.5th, data are not applicable (sample did not survive to 5th instar.
date.6th	date	date of molt to 6th instar. NA is not applicable (insect did not survive to 6th instar or wandered in the 5th instar)
mass.6th	numeric (mg)	Mass on the day of molt to 6th instar. NA is not available if there is a date in date.6th (mass was missed for this sample on this day). If no date in date.6th, data are not applicable (sample did not survive to 6th instar, or wandered prior to this point).
mass.7th	numeric (mg)	Mass on the day of molt to 7th instar. NA is not available if there is a date in date.6th (mass was missed for this sample on this day). If no date in date.7th, data are not applicable (sample did not survive to 7th instar, or wandered prior to this point).
date.7th	date	date of molt to 7th instar. NA is not applicable (insect did not survive to 7th instar or wandered in the 5th or 6th instar)
date.wander	date	date of observation of wandering. Defined as observing visible dorsal vein and characteristic wandering behavior (insect is highly mobile walking circles around its enclosure).
mass.wander	numeric (mg)	mass upon observation of wandering. NA is not applicable if no date in date.wander (insect did not survive to wandering), or not available if there is a date in date.wander (data were not collected for mass of this sample)
notes_dev	notes	notes on development
date.temp.in	date	date the sample was entered into the treatment temperature in environmental chambers. Always same day of molt to 4th instar. NA in this column means data were not applicable (sample died prior to entering the temperature treatment).
chamber.time.temp.in	time	time of day the sample was entered into the treatment temperature in environmental chambers. NA in this column means data were not applicable (sample died prior to entering the temperature treatment).
time.temp.in	time	time of day outside the chambers that the sample was entered into the treatment temperature in environmental chambers. Chambers were set to mimick an earlier time of day to facilitate logistical experimental work during a more agreeable time of day. NA in this column means data were not applicable (sample died prior to entering the temperature treatment).
date.prime	date	date of initial infection
chamber.time.prime	time	time of day the sample was initially infected. NA in this column means data were not applicable (sample died prior to the initial infection treatment).
time.prime	time	time of day outside the chambers that the sample received the initial infection. Chambers were set to mimick an earlier time of day to facilitate logistical experimental work during a more agreeable time of day. NA in this column means data were not applicable (sample died prior to this treatment).
primedose	dose (CFU/10uL)	dose of initial infection included in the 10uL syringe. Refers to the actual number of CFUs the insect received. NA in this column means not applicable (insect died prior to this point)
prime_inj_vol	numeric (uL)	microliters (uL) of injection received. Always 10uL for Bt or sham injections, and 0 for unmanipulated controls
time.temp.out	time	time of day outside the chambers that the sample was removed from the temperature treatment and placed at 25C+-10 baseline temperature regime. Chambers were set to mimick an earlier time of day to facilitate logistical experimental work during a more agreeable time of day. NA in this column means data were not applicable (sample died prior to this timepoint).
chamber.time.temp.out	time	time of day the sample was removed from the treatment temperature in environmental chambers. NA in this column means data were not applicable (sample died prior to this timepoint).
date.temp.out	date	date the sample was removed from the temperature treatment and returned to 25C+-10 baseline thermal regime. the temperature treatment lasted 3 days.
mass.challenge	numeric (mg)	mass of the sample at the time of the secondary infection immune challenge. NA in this column means not applicable if there is a date in date.challenge, and not available if there is no date in date.challenge (ie the insect died prior to this timepoint)
date.challenge	date	date of secondary infection immune challenge. NA in this column means not applicable (insect died prior to this time point)
chamber.time.challenge	time	time of secondary infection treatment. NA in this column means not applicable (insect died prior to this time point)
time.challenge	time	time of day outside the environmental chamber that the secondary infection treatment took place. Chambers were set to mimick an earlier time of day to facilitate logistical experimental work during a more agreeable time of day. NA in this column means not applicable (insect died prior to this time point)
challenge_goalCFU	dose (CFU/25uL)	dose of secondary infection included in the 25uL syringe. Refers to the actual number of CFUs the insect received. NA in this column means not applicable (insect died prior to this point)
challenge_vol	numeric (uL)	microliters (uL) of injection received. Always 25uL for Bt or sham injections, and 0 for unmanipulated controls
notes	notes	notes about the experiment and the way it was conducted for this sample if it deviated in any way from the standardized experimental protocol

bledLarvae_from_prime.csv is a datasheet for larvae that were bled to test for presence of bacterial colonies (in supplement). there's a section of the code that uses it to visualize, but is not necessary for the manuscript. Below is a readme for the columns in the data sheet.

column	units	description
Population	categorical	population of Manduca sexta the sample originated from. lab or field
Initial infection	categorical	initial infection the sample received. Bt=Bacillus thuringiensis low dose; Sham=sham injection with sterile PBS
Temperature	categorical	temperature treatment regime the insect was assigned starting at 1st day of fourth instar. Lasted 3 days. HW=heat wave of 32 degrees C +/-10; noHW=25 degrees C+/-10
No. larvae setup	count	number of cultures set up from larval blood
No. with colonies 1 day post initial infection	count	number of culture plates with bacterial cultures present the day after infection took place. Blood was taken 1 day after the infection and allowed to incubate for 24 hours before reading plates.
No. with colonies day of molt to 5th	count	number of culture plates with bacterial cultures present on the day of molt to 5th instar. Blood was taken the day of molt to 5th instar and allowed to incubate for 24 hours before reading plates.
No. with colonies day after molt to 5th	count	number of culture plates with bacterial cultures present on the day after molt to 5th instar. Blood was taken the day after molt to 5th instar and allowed to incubate for 24 hours before reading plates.

Code/Software

The code provided (.Rmd file) uses the two datasheets listed above. All data cleaning, analysis, and figure generation are in the code. All coding done in R (version of software and libraries reported in main manuscript).