Bees bred for Varroa sensitive hygiene trait demonstrate resistance to chalkbrood disease
Data files
Jun 10, 2025 version files 64.13 KB
-
BTRData24.csv
2.56 KB
-
Carver2023RStudio.csv
2.66 KB
-
Carver2024.csv
4.26 KB
-
Carver23_24.csv
2.99 KB
-
ManuscriptCode4.15.25.Rmd
45.48 KB
-
README.md
6.18 KB
Jun 23, 2025 version files 64.52 KB
-
BTRData24.csv
2.84 KB
-
Carver2023RStudio.csv
2.66 KB
-
Carver2024.csv
4.26 KB
-
Carver23_24.csv
2.99 KB
-
ManuscriptCode4.15.25.Rmd
45.48 KB
-
README.md
6.28 KB
Abstract
To improve health and vitality of honey bees, Apis mellifera, beekeepers can propagate stocks that demonstrate resistance to both parasites and pathogens. Most breeding programs focus on resistance to Varroa destructor mites and/or brood pathogens. Colonies bred specifically the trait Varroa Sensitive Hygiene (VSH) have never been explicitly tested for resistance to brood disease. The goal of this study was to test if colonies bred for VSH are both mite and disease resistance. Over two years (2023 and 2024) and in two locations (University of Minnesota and the USDA-ARS lab in Baton Rouge, Louisiana), we compared colonies from the POL line bred specifically for Varroa resistance to colonies from a commercial source that were not selected specifically for Varroa resistance but were selected for “general” hygienic behavior using the freeze-killed brood (FKB) assay. We challenged colonies within each line with Ascosphara apis, that causes chalkbrood, and quantified mites, disease and hygienic behavior. Our study demonstrated that colonies from the POL line bred for VSH are just as resistant to chalkbrood as bees from a Commercial line bred for hygienic behavior by the FKB assay. Results confirmed that the POL line is more mite resistant than the Commercial, as it had significantly lower mites in two of three trials. Both the POL and Commercial colonies had high levels of hygienic behavior as measured by the FKB assay. These results indicate that honey bees selected for VSH respond to both mite-infested and disease-infected brood. Further comparative studies are needed to clarify any differences in genetic mechanisms and olfactory sensitivity mediating the VSH-trait and general hygienic behavior. On a practical level, using lines of honey bees selected for VSH in beekeeping operations could help curb losses, improve honey bee health, and reduce financial burdens caused by Varroa and diseases.
Dataset DOI: 10.5061/dryad.v6wwpzh6p
Description of the data and file structure
R script, and CSV files used to investigate chalkbrood resistance, mite resistance, and hygienic behavior in two lines of bees (a mite-resistant line and a line bred for general hygienic behavior) in Minnesota (2023 and 2024) and Louisiana, USA (2024). These data are associated with a manuscript that is currently under review. The data set contains four CSV files:
- from Minnesota 2023 (Carver2023RStudio)
- from Minnesota 2024 (Carver2024)
- compilation of the two datasets from Minnesota over the two years (Carver23_24)
- and from the experiment in Louisiana 2024 (BTRData24)
All csv files are coded to load into the ManuscriptCode file. This file contains all the code used to compare chalkbrood score, mite loads, colony strength, and hygienic behavior between the two queen lines. As well as code for all visualizations.
Files and variables
File: ManuscriptCode4.15.25.rmd
Description: This is the R markdown file that loads all the CSV files used and the code used for all statistical tests and visualizations in the manuscript.
File: Carver23_24.csv
Description: This is data from Minnesota 2024 and 2023 in one file for metric comparison between the years. Cells that are blank (missing values) or containing NA values indicate that data was unable to be collected for that metric measured.
Variables
- Stand:: Stand ID number
- Colonynumb: Colony ID number
- Queen: Queen line (P = Pol line or C = Commercial line)
- Year: 2023 or 2024 (year of study)
- pre_mites: mites/100 adult bees pre-challenge
- post_mites: mites/100 adult bees post-challenge
- Fr_Bees: Frames of bees counted pre-challenge
- Fr_Brood: Frames of brood counted pre-challenge
- Br_Pt: Brood pattern (scored 1-5) pre-challenge
- Strict_FKB: Percent of freeze killed brood removed in 24 hours
- week1_CB: Chalkbrood severity score at 1 week post-challenge
- week2_CB: Chalkbrood severity score at 2 weeks post-challenge
File: BTRData24.csv
Description: Data from study replication done in Baton Rouge, LA, in 2024
Variables
- Colony: Colony ID number
- Queen: Queen line (It = Commercial, P = Pol-line)
- peak: Peak infection (combination of early signs and mummies at 4 days post challenge)
- 7.15_chalk: Chalkbrood severity at 1 week
- 7.15_brood: Brood area at 1 week
- 7.12_chalk: Chalkbrood severity at 4 days
- 7.12_brood: Brood area at 4 days
- 7.10_chalk: Chalkbrood severity at 2 days
- 7.10_brood: Brood area at 2 days
- Strict_FKB: Strict percent of FKB removed in 24 hours
- Liberal_FKB: Liberal percent of FKB removed in 24 hours
- june_mites: Mites/100 adult bees pre-challenge
- 7.10_early_zeros: Early sign severity at 2 days post-challenge
- 7.12_early_zeros: Early sign severity at 4 days post-challenge
- 7.15_melty: Early sign severity at 1 week post-challenge
File: Carver2024.csv
Description: Data from study in Minnesota 2024. Cells that are blank (missing values) or containing NA values indicate that data was unable to be collected for that metric measured.
Variables
- Stand:: Stand ID
- Colony #:: Colony ID
- Queen: Queen line (P = Pol-line, C = Commercial line)
- Peak: Peak infection (combination of early sign and mummy severity at 1 week post challenge)
- may_mites: Initial mites/100 adult bees (this was the mite load right after we re-queened to see if the packages we made up needed to be treated)
- june_mites: Mites/100 adult bees pre-challenge
- aug_mites: Mites/100 adult bees post-challenge
- Fr_Bees: Frames of bees pre-challenge
- Fr_Brood: Frames of brood pre-challenge
- Br_Pt: Brood pattern pre-challenge (ranked 1-5)
- Fr_BeesAug: Frames of bees post-challenge
- Liberal_FKB: Percent of FKB removed in 24 hours (liberal)
- Strict_FKB: Percent of FKB removed in 24 hours (strict)
- 6.29_CB: Chalkbrood severity at 4 days
- 6.29_brood: Brood area at 4 days
- 7.1_CB: Chalkbrood severity at 1 week
- 7.1_brood: Brood area at 1 week
- 7.5_CB: Chalkbrood severity at 12 days
- 7.5_brood: Brood area at 12 days
- 7.8_CB: Chalkbrood severity at 2 weeks
- 7.8_brood: Brood area at 2 weeks
- 7.11_CB: Chalkbrood severity at 17 days
- 7.11_brood: Brood area at 17 days
- 7.15_CB: Chalkbrood severity at 3 weeks
- early2avg: Early sign severity at 2 days
- early4avg: Early sign severity at 4 days
- early1weekavg: Early sign severity at 1 week
- early12avg: Early sign severity at 12 days
- early2weeksavg: Early sign severity at 2 weeks
- early3weeksavg: Early sign severity at 3 weeks
File: Carver2023RStudio.csv
Description: Data from study in Minnesota 2023. Cells that are blank (missing values) or containing NA values indicate that data was unable to be collected for that metric measured.
Variables
- Colonystand: Stand ID
- Colonynumb: Colony ID
- Queen: Queen lines, *indicated queens that the breeder thought were extra special
- Queen Clean: Queen lines without *for coding purposes (O = Commercial Line, P = Pol-line, H = MN HYG which were not analyzed in this study)
- june29mites: Mites pre-challenge
- august1mites: Mites mid-challenge in a subset of colonies
- sep7mites: Mites post-challenge
- july19chalk: Chalkbrood severity at 1 week
- july28chalk: Chalkbrood severity at 2 weeks
- Strict_FKB: % freeze-killed brood removed at 24 hours (strict)
- Liberal_FKB: % freeze-killed brood removed at 24 hours (liberal)
- JuneFr_Brood: Frames of brood pre challenge
- JuneFr_Bees: Frames of bees post challenge
- JuneBrood_Pt: Brood pattern (1-5) pre-challenge
- AugFr_Brood: Frames of brood post challenge
- AugBrood_Pt: Brood pattern (1-5) post challenge
- 1weekFr_Brood: Frames of brood at 1 week post challenge
- 2weekFr_Brood: Frames of brood at 2 weeks post challenge
Code/software
R Statistical software, version 4.3.1
Performance (to check for model assumptions) and ggplot2 (for visualizations) packages. All code used is in the file titled ManuscriptCode4.15.25.rmd
Version changes:
20-June-2025: Updated column F in BTRData2024.csv which was miscalculated.