DOI: 10.5061/dryad.zpc866ths
title: Microsporidian parasite impairs colony fitness in bumblebees

description: Emerging infectious diseases can have a major impact on the fitness of
 novel hosts, thereby contributing to ongoing species declines. In social
 insects, collaborative brood care by workers and successful mating of male
 sexuals are key to colony fitness. The microsporidian
 endoparasite, Nosema ceranae, has spread almost
 globally, shifting across honeybee species and now to bumblebees. However,
 despite N. ceranae being linked to recent population declines,
 its possible impact on bumblebee colony fitness remains poorly understood.
 Here, we show that N. ceranae infections can significantly impact
 Bombus terrestris worker feeding glands, as well as the
 longevity, sperm quality, and mating abilities of drones. In the
 laboratory, workers and drones were exposed to either the parasite or not.
 Then, parasite infection rates and loads, as well as lethal and sublethal
 parameters were assessed. Infected drones revealed higher parasite
 infection rates and spore titres as well as mortality compared to female
 workers, suggesting sex-specific susceptibility. Furthermore, infections
 impaired feeding glands, sperm traits, and altered mating behaviour - all
 of which are key to colony fitness. Our findings provide a mechanistic
 explanation on how N. ceranae contributes to the ongoing decline
 of wild bumblebee populations, calling for respective mitigation measures.
description: # Microsporidian parasite impairs colony fitness in bumblebees GENERAL
 INFORMATION 1. Title of Dataset: Microsporidian parasite impairs colony
 fitness in bumblebees 2. Author Information A. Principal Investigator
 Contact Information Name: Domenic W. Camenzind Institution: Institute of
 Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
 Address: Schwarzenburgstrasse 161, 3097 Liebefeld, Bern, Switzerland
 Email: [domenic.camenzind@unibe.ch](mailto:domenic.camenzind@unibe.ch) 3.
 Date of data collection (single date, range, approximate date): Between
 May and September 2019 4. Geographic location of data collection: The
 study was performed at the Institute of Bee Health (IBH), University of
 Bern, Switzerland 5. Information about funding sources that supported the
 collection of the data: Support was provided by the Vinetum Foundation to
 L.S. There was no additional external funding received for this study.
 **DATA & FILE OVERVIEW** 1. File List: Excel file (**Microsporidian
 parasite impairs fitness in bumblebees_Dryad.xlsx**) has three sheets.
 Sheets 1 (**Consumption_Survival**), 2 (**Mating**), and 3 (**HPG)** have
 the complete raw data required to repeat all the statistical analyses. 2.
 Relationship between files, if important: Yes, however, all statistical
 tests can be run independently as all the relevant data is provided per
 sheet. 3. Additional related data collected that was not included in the
 current data package: None. 4. Are there multiple versions of the dataset?
 No. **DATA-SPECIFIC INFORMATION FOR SHEET 1**
 ('Consumption_Survival'): 1. Number of variables: 17 2. Number
 of cases/rows: 248 3. Variable List: Specimen: Number identifying each
 individual bees Treatment: This is the name of the respective treatment
 Sex: Sex of the bee: male (1) or female (2) Start_mass_[mg]: Mass in mg of
 the individual at the begin of the experiment End_mass_[mg]: Mass in mg of
 the individuals surviving of the experimental period Mass_change_[mg]:
 Start mass [mg] - End mass [mg] Survival: Days the bee survived during the
 experimental perion Status: Did the bee survive the entire experimental
 period, yes (1) or no (0) Consumption_SW_1: Amount of sugar water consumed
 during experimental days 0-4 Consumption_SW_2: Amount of sugar water
 consumed during experimental days 4-8 Consumption_SW_3: Amount of sugar
 water consumed during experimental days 8-12 Total_SW: Total sugar water
 consumed, sum of Consumption SW 1, Consumption SW 2 and Consumption SW 3
 Total_Pollen: Amount of pollen the bee consumed [g] Spore_count: Total
 spores found in gut of surviving individuals Sperm_count: Total sperm
 count of surviving drones Sperm_viability_[%]: Viability of sperm in % of
 surviving drones Total_living_sperm: Sperm_viability [%] * Sperm_count 1.
 Missing data codes: NA. 2. Specialized formats or other abbreviations
 used: None. **DATA-SPECIFIC INFORMATION FOR SHEET** **2**
 ('Mating'): 1. Number of variables: 9 2. Number of cases/rows:
 45 3. Variable List: Gyne_ID: Number of the individual gyne (i.e.,
 specimen) Drone_ID: Number of the individual drone mated with the gyne
 (i.e., specimen), corresponds to "Specimen" in the
 "Consumption & Survival" sheet N_Nosema_spores: Number of
 spores found in the gut of the drone Treatment: Control (1) or parasite
 (3) treatment Round: Mating round of drone, if not successful drones were
 submitted to a second round. Start: Time of the day when drone & gyne
 were placed into mating arena together in HH:MM Copulation_Start: Time of
 the day when copulation started in HH:MM Copulation_End: Time of the day
 when copulation finished in HH:MM Recognition_duration: Time passed
 between placing drone & gyne in mating arena and begin of copulation
 in HH:MM (i.e. "Start" - "Copulation Start")
 Mating_duration: Time passed between start and end of copulation in HH:MM
 Successful_mating: Did the drone manage to initiate mating with the gyne?
 Yes (1) or no (0) Sperm_viability: Viability of sperm in % of drone
 Sperm_count: Total sperm count of drone Total_living_sperm:
 Sperm_viability * Sperm_count 1. Missing data codes: NA. 2. Specialized
 formats or other abbreviations used: None. **DATA-SPECIFIC INFORMATION FOR
 SHEET** 3 ('HPG'): 1. Number of variables: 4 2. Number of
 cases/rows: 885 3. Variable List: Bee_ID: Number of the individual worker
 bee, corresponds to "Specimen" in the "Consumption &
 Survival" sheet Treatment: Treatment group Measurement: Number of
 measurement conducted per bee, in total 30 repetitions HPG_Diameter_[µm]:
 Diameter of individual HPG-acini in µm 1. Missing data codes: NA. 2.
 Specialized formats or other abbreviations used: None.