Body mass, temperature, and pathogen intensity differentially affect critical thermal maxima and their population-level variation in a solitary bee
Data files
Feb 23, 2024 version files 143.15 KB
Abstract
Climate change presents a major threat to species distribution and persistence. Understanding what abiotic or biotic factors influence the thermal tolerances of natural populations is critical to assessing their vulnerability under rapidly changing thermal regimes. This study evaluates how body mass, local climate, and pathogen intensity influence heat tolerance and its population-level variation (SD) among individuals of the solitary bee Xenoglossa pruinosa. We assess the sex-specific relationships between these factors and heat tolerance given the differences in size between sexes and the ground-nesting behavior of the females. We collected X. pruinosa individuals from fourteen sites across Pennsylvania, USA that varied in mean temperature, precipitation, and soil texture. We measured the critical thermal maxima (CTmax) of X. pruinosa individuals as our proxy for heat tolerance, and used quantitative PCR to determine relative intensities of three parasite groups—trypanosomes, Spiroplasma apis (mollicute bacteria), and Vairimorpha apis (microsporidian). While there was no difference in CTmax between the sexes, we found that CTmax increased significantly with body mass, and that this relationship was stronger for males than for females. Air temperature, precipitation, and soil texture did not predict mean CTmax for either sex. However, population-level variation in CTmax was strongly and negatively correlated with air temperature, which suggests that temperature is acting as an environmental filter. Of the parasites screened, only trypanosome intensity correlated with heat tolerance. Specifically, trypanosome intensity negatively correlated with the CTmax of female X. pruinosa but not males. Our results highlight the importance of considering size, sex, and infection status when evaluating thermal tolerance traits. Importantly, this study reveals the need to evaluate trends in the variation of heat tolerance within and between populations, and consider implications of reduced variation in heat tolerance for the persistence of ectotherms in future climate conditions.
README: Body mass, temperature, and pathogen intensity differentially affect critical thermal maxima and their population-level variation in a solitary bee
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Jones, L. J., Miller, D. A., Schilder, R. J., López-Uribe, M. M. (2024). Body mass, temperature, and pathogen intensity differentially affect critical thermal maxima and their population-level variation in a solitary bee. Ecology and Evolution, 14(2), e10945. https://doi.org/10.1002/ECE3.10945
Raw data and R code are available here: https://doi.org/10.5061/dryad.hhmgqnkp9
General Information
The raw data presented in Jones et al. (2024) are included. This study aimed to understand what abiotic and biotic factors, such as temperature and pathogen intensity, influence heat tolerance and its variation among natural populations of the solitary bee Xenoglossa pruinosa. Data per individual Xenoglossa pruinosa, including date and location of collection, mass, CTmax, and parasite intensity, are included in file 'Jones-et-al_Raw_Individual_Data.csv'. Data summarized per collection site, including environmental data and bee data averages per sex at each site, are included in file 'Jones-et-al_Raw_Site_Data.csv'. Please review the methods (2.1-2.4) and extended methods (Appendix) sections in Jones et al. (2024) for information on data collection.
Collection year: 2019
Collection sites: 14 Cucurbita (e.g., pumpkin and squash) farms in Pennsylvania (USA)
Study organism: 220 female and 200 male squash bees (Xenoglossa pruinosa)
Data
Jones-et-al_Raw_Individual_Data.csv
A. Sample ID - unique ID assigned to each individual.
B. Species - species identification of that individual (identification provided by Laura J. Jones).
C. Sex - sex of the individual.
D. Collection_Date - date that the individual was collected from the field.
E. Site - site ID (town) that the individual was collected from.
F. Latitude - abbreviated latitude for the site that the individual was collected from.
G. Longitude - abbreviated longitude for the site that the individual was collected from.
H. Time_Chill_Coma_minutes - the amount of time (minutes) that the individual was kept in chill coma (i.e., on ice) during transport.
I. Mass_Before_CTmax_mg - the mass of the individual collected before CTmax experiments were performed.
J. Mass_After_CTmax_mg - the mass of the individual collected after CTmax experiments were performed.
K. deltaMass_mg - the difference in mass before and after the CTmax experiment.
L. CTmax_Celsius - the critical thermal maximum (CTmax) recorded for that individual using a ramping rate of + 0.25 °C/min.
M. Time_to_CTmax_min - the total time that the individual was kept in the temperature ramping experiment before reaching their CTmax.
N. 28sReferenceGene_RawCT_Mean - the average cycle threshold (CT) between the three replicates for the quantification of the 28S reference gene for Apocrita for that individual.
O. Trypanosome_RawCT_Mean - the average cycle threshold (CT) between the three replicates for the quantification of trypanosomes for that individual.
P. Trypanosome_DeltaCT - the average CT for trypanosomes for the individual minus the average CT for the reference gene for the same individual.
Q. Trypanosome_ddCT - the delta CT for trypanosomes for the individual minus the maximum delta CT calculated for trypanosomes (within this dataset).
R. Trypanosome_2^-ddCT - the 2^(-ddCT for trypanosomes) for that individual.
S. Trypanosome_log(2^-ddCT) - the log10(2^-ddCT for trypanosomes) for that individual.
T. Trypanosome_RelativeIntensity_AdjustedforThreshold - the relative quantification for trypanosomes within the cycle threshold of < 35, where any sample with a raw CT mean greater than 35 is considered negative (zero).
U. Vairimorpha_apis_RawCT_Mean - the average cycle threshold (CT) between the three replicates for the quantification of Vairimorpha apis for that individual.
V. Vairimorpha_apis_DeltaCT - the average CT for Vairimorpha apis for the individual minus the average CT for the reference gene for the same individual.
W. Vairimorpha_apis_ddCT - the delta CT for Vairimorpha apis for the individual minus the maximum delta CT calculated for Vairimorpha apis (within this dataset).
X. Vairimorpha_apis_2^-ddCT - the 2^(-ddCT for Vairimorpha apis) for that individual.
Y. Vairimorpha_apis_log(2^-ddCT) - the log10(2^-ddCT for Vairimorpha apis) for that individual.
Z. Vairimorpha_apis_RelativeIntensity_AdjustedforThreshold - the relative quantification for Vairimorpha apis within the cycle threshold of < 35, where any sample with a raw CT mean greater than 35 is considered negative (zero).
AA. Spiroplasma_apis_RawCT_Mean - the average cycle threshold (CT) between the three replicates for the quantification of Spiroplasma apis for that individual.
AB. Spiroplasma_apis_DeltaCT - the average CT for Spiroplasma apis for the individual minus the average CT for the reference gene for the same individual.
AC. Spiroplasma_apis_ddCT - the delta CT for Spiroplasma apis for the individual minus the maximum delta CT calculated for Spiroplasma apis (within this dataset).
AD. Spiroplasma_apis_2^-ddCT - the 2^(-ddCT for Spiroplasma apis) for that individual.
AE. Spiroplasma_apis_log(2^-ddCT) - the log10(2^-ddCT for Spiroplasma apis) for that individual.
AF. Spiroplasma_apis_RelativeIntensity_AdjustedforThreshold - the relative quantification for Spiroplasma apis within the cycle threshold of < 35, where any sample with a raw CT mean greater than 35 is considered negative (zero).
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Jones-et-al_Raw_Site_Data.csv
A. Site - the unique site ID (town).
B. Latitude - abbreviated latitude for the site.
C. Longitude - abbreviated longitude for the site.
D. Species - the species of the individuals pooled in site averages for variables provided in columns F-J: average and SD of mass, time in chill coma, and average and SD of CTmax.
E. Sex - the sex of the individuals pooled in site averages for variables provided in columns F-J: average and SD of mass, time in chill coma, and average and SD of CTmax.
F. Average_Mass_mg - the average mass of Xenoglossa pruinosa individuals of a given sex collected from that site. This average is calculated from the mass of individuals before CTmax experiments were performed.
G. StandardDeviation_Mass_mg - the standard deviation in mass of Xenoglossa pruinosa individuals of a given sex collected from that site. SD is calculated from the mass of individuals before CTmax experiments were performed.
H. Time_Chill_Coma_minutes - the number of minutes that Xenoglossa pruinosa individuals were stored in ice during transport from the site to the Pennsylvania State University where experiments took place.
I. CTmax_Average_Celsius - the average CTmax of Xenoglossa pruinosa individuals of a given sex collected from that site.
J. CTmax_StandardDeviation_Celsius - the standard deviation in CTmax of Xenoglossa pruinosa individuals of a given sex collected from that site.
K. Soil_Composition - the soil texture class assigned to the pooled soil sample from that site given its proportions of sand, silt, and clay.
L. Proportion_Sand_% - the proportion (%) of sand in the soil from that site.
M. Proportion_Silt_% - the proportion (%) of silt in the soil from that site.
N. Proportion_Clay_% - the proportion (%) of clay in the soil from that site.
O. HOBO_Probe_August_Daily_Average_Tmin_Celsius - the average daily minimum temperature (Tmin) during the month of July (2019) at the site averaged from two shielded HOBO temperature probes in the field. These probes collected temperature information every hour.
P. HOBO_Probe_August_Daily_Average_Tmax_Celsius - the average daily maximum temperature (Tmax) during the month of July (2019) at the site averaged from two shielded HOBO temperature probes in the field. These probes collected temperature information every hour.
Q. PestWatch_July_Daily_Average_Tmin_Celsius - the average daily minimum temperature (Tmin) during the month of July (2019) at the site collected from the model PestWatch.
R. PestWatch_July_Daily_Average_Tmax_Celsius - the average daily maximum temperature (Tmax) during the month of July (2019) at the site collected from the model PestWatch.
S. PestWatch_August_Daily_Average_Tmin_Celsius - the average daily minimum temperature (Tmin) during the month of August (2019) at the site collected from the model PestWatch.
T. PestWatch_August_Daily_Average_Tmax_Celsius - the average daily maximum temperature (Tmax) during the month of August (2019) at the site collected from the model PestWatch.
U. PRISM_Precipitation_July_mm - the average amount of precipitation (mm) during the month of July (2019) at the site collected from the PRISM climate dataset.
V. SoilTexture_PC1 - the principle component 1 calculated from the proportions of sand, silt, and clay using principle component analysis (PCA).
W. SoilTexture_PC2 - the principle component 2 calculated from the proportions of sand, silt, and clay using principle component analysis (PCA).
X. SoilTexture_PC3 - the principle component 3 calculated from the proportions of sand, silt, and clay using principle component analysis (PCA).
Software and Packages
All analyses were conducted in R (v.4.1.2) and can be reviewed in file 'Jones-et-al_R_Code.R'. Detailed description of analysis and packages used can be reviewed in the methods (2.5) and extended methods (Appendix) sections in Jones et al. (2024).
Relevant Information for Analyses
We performed all analyses with and without two individuals (sample IDs epl0331 and epl0647) because these were considered in poor condition and outliers within the dataset. In Jones et al. (2024), we present the analyses that exclude these individuals.