DOI: 10.5061/dryad.hhmgqnkp9
title: Body mass, temperature, and pathogen intensity differentially affect critical thermal maxima and their population-level variation in a solitary bee

description: 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. 
description: # Body mass, temperature, and pathogen intensity differentially affect
 critical thermal maxima and their population-level variation in a solitary
 bee *Access the full article with contact information here*: 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.
 *Raw data and R code are
 available here*: ##
 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
 &lt; 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 &lt;
 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 &lt;
 35, where any sample with a raw CT mean greater than 35 is considered
 negative (zero). \__________________________________\_ ####
 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.