DOI: 10.5061/dryad.1g1jwsv54
title: Data from: Co-exposure to a honeybee pathogen and an insecticide: Synergistic effects in a new solitary bee host but not in Apis mellifera

description: Pesticides and pathogens are major drivers of bee declines. However, their
 potential interactions are poorly understood, especially for non-Apis
 bees. This study assessed the combined effects of infestation by the
 honeybee pathogen Vairimorpha ceranae and chronic exposure to the
 insecticide flupyradifurone on Osmia bicornis and Apis mellifera. We
 investigated whether V. ceranae could reproduce in a new solitary bee host
 (O. bicornis) and assessed sublethal and lethal effects of the pathogen
 and the pesticide, alone and in combination. We also analyzed the
 interactive effects of the combined exposure on V. ceranae proliferation
 and bee survival in the two bee species. Newly-emerged bees were orally
 infected with 100,000 spores of V. ceranae and then exposed ad libitum to
 flupyradifurone at field-realistic concentrations. We showed, for the
 first time, that V. ceranae can replicate in the midgut of O. bicornis,
 causing histological damage, impaired phototactic response, reduced food
 consumption, and decreased longevity. The pathogen-pesticide combination
 caused a synergistic effect in O. bicornis, leading to an abrupt survival
 decline. In A. mellifera, V. ceranae and flupyradifurone showed
 antagonistic survival effects, but the pesticide promoted pathogen
 proliferation. Our results warn against the potential effects of pathogen
 spillover and multiple stressor exposure on non-Apis bees.
description: This dataset was collected during the study investigating the
 effects of co-exposure to a honeybee pathogen and an insecticide on
 solitary bees and <em>Apis mellifera</em>. Data were obtained
 through controlled laboratory experiments, where bees were exposed to
 different treatment conditions including oral exposure to the insecticide
 flupyradifurone and oral inoculation with spores of the
 pathogen <em>Vairimorpha ceranae</em>. Behavioral responses,
 survival rates, pathogen replication, and cellular alterations were
 recorded at predefined time points. Following data
 collection, raw measurements were processed using R statistical software.
 Statistical analyses were conducted using generalized linear models
 (GLMs), survival analysis, and additional exploratory analyses were
 performed to assess potential interactions between factors.
 All raw data, R code, and a README file detailing variable
 descriptions and data structure are included in the dataset
 repository.
description: # Co-exposure to a honeybee pathogen and an insecticide: synergistic
 effects in a new solitary bee host but not in *Apis mellifera*
 [https://doi.org/10.5061/dryad.1g1jwsv54](https://doi.org/10.5061/dryad.1g1jwsv54) The files contain raw data from the manuscript: "Co-exposure to a honeybee pathogen and an insecticide has a synergistic effect on survival in a solitary bee". And the two R code scripts used in the analysis. Data was collected during laboratory experiments with *Osmia bicornis* and *Apis mellifera* by daily observation of mortality and food consumption. ## Description of the data and file structure The files are divided according to the type of analysis used to produce the results: survival analyses, median lethal time (LT50), food consumption and pesticide dose, pathogen spores replication, and phototaxis test results. We used two bee species: Osmia bicornis and Apis mellifera. Food consumption, spores replication, and survival data are available for both species. The phototaxis test was performed only on Osmia bicornis. The experimental groups are represented in the file by a code terminology, as described below: Experimental groups - Codes used in the sheets Control - C Flupyradifurone (4.38 mg/L) - F Flupyradifurone (15 mg/L) - FH Vairimorpha (Nosema) ceranae - V or N V. ceranae + Flupyradifurone (4.38 mg/L) - V+F or N+F V. ceranae + Flupyradifurone (15 mg/L) - V+FH or N+FH ## **Dataset Descriptions** Each file contains specific data related to the respective experiment. Below is a summary of each dataset, including column descriptions and units where applicable.  **1. Consumption.csv** This file contains food consumption data (in milliliters) over 10 days of pesticide exposure for both *Apis mellifera* and *Osmia bicornis*. It also includes the estimated dose intake of Flupyradifurone. Trat: Treatment group code combined with the bee species initial letter Species: Bee species used Block: experimental block Group: code of the experimental group Bee_Id: unique ID assigned to each individual Food_cons_mL: Food consumption in milliliters (mL) Day: day of the experiment counted from the first day of pesticide exposure to last day alive of the bee. Dose_mg.bee: amount of pesticide consumption in mg/bee calculated by the multiplication of the volume of food consumption and pesticide concentration Dose_ng.bee: the amount of pesticide consumption in ng/bee calculated by the multiplication of the volume of food consumption and pesticide concentration Nosema: no/yes identification if the individual consumed the pathogen spores **2. Survival_Osmia.csv** This file contains survival data for *Osmia bicornis* after ingestion of *Vairimorpha ceranae* spores and exposure to Flupyradifurone. Nosema: Binary variable indicating the presence (1) or absence (0) of *V. ceranae* Flupyradifurone: Binary variable indicating presence (1) or absence (0) of the insecticide Bee_Id: unique ID assigned to each individual Group: code of the experimental group Day: identification of the day in which occurred the event assessed (bee death) Status: Survival status (0 = censored data, bee was alive at the last time point measured; 1 = mortality event recorded) Size_bee: inter-tegular distance in milimeters as a proxy for bee body size **3. LT50_Osmia.csv** Data used to calculate the median lethal time (LT50) for *Osmia bicornis*. Group: code of the experimental group Day: Day of the experiment when death occurred Response: Cumulative number of dead bees up to that day Survive: Number of bees still alive on that day Total: total of bees assessed obtained by the sum of response and survive data **4. Survival_Apis.csv** Survival data for *Apis mellifera* following ingestion of *Vairimorpha ceranae* spores and exposure to Flupyradifurone. Nosema: Binary variable indicating the presence (1) or absence (0) of *V. ceranae* Flu_low: Binary variable indicating presence (1) or absence (0) of Flupyradifurone (4.38 mg/L) Flu_high: Binary variable indicating presence (1) or absence (0) of Flupyradifurone (15 mg/L) Group: code of the experimental group Repetition: experiment repetition Day: day of the experiment counted from the first day of pesticide exposure to the last day alive of the bee. Total: total of bees assessed obtained by the sum of dead and alive individuals Dead: Number of dead bees on that day Alive: Number of bees still alive on that day **5. LT50_Apis.csv** Data used to calculate the median lethal time (LT50) for *Apis mellifera*. Group: code of the experimental group Day: Day of the experiment when death occurred Response: Cumulative number of dead bees up to that day Survive: Number of bees still alive on that day Total: total of bees assessed obtained by the sum of response and survive data **6. Spores.csv** Number of *Nosema ceranae* spores replicated after seven days from inoculation. Species: Bee species used Group: code of the experimental group Rename_Group: renamed code of the experimental group replacing N for V Spore_number: number of pathogen spores estimated by rtPCR Log: Log-transformed value of the spore count Missing data: NA **7. Phototaxis.csv** Behavioral data from the phototaxis test performed on *Osmia bicornis* using video tracking. ID: Unique identifier for each bee. Block: Experimental block. Group: Code of the experimental group. Day: Date of video recording (dd/mm/yyyy). Video_duration_seconds: Duration of the recording in seconds. Moving_threshold: Threshold used by the AnimalTA software to detect bee movement; adjusted for each individual to avoid false positives. Proportion_time_moving: Proportion (ranging from 0 to 1) of the recorded time that the bee was moving. Average_Speed_Moving: Average speed, calculated based on the time and distance moved while the bee was in motion. Traveled_Distance_Moving: Total distance moved during the recording time, measured in centimeters. Line_crossed: number of times that bee crossed the line dividing the dark and light areas during video analysis. Latency_line: Time in seconds taken by the individual to reach the line. Proportion_time_light_area: Proportion (ranging from 0 to 1) of the recorded time that the bee spent in the light area. Latency_inside_light_area: Time in seconds taken by the individual to reach the light area. Prop_time_release_area: Proportion (ranging from 0 to 1) of the recorded time that the bee spent in the release area. Missing data: NA ## R code files Data_*analysis*_Apis: script from R used to analyze data from Apis mellifera species Data_*analysis_Osmia*_Nosema: script from R used to analyze data from Osmia bicornis species