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The more the better: Fatty acids are predictive markers of honey bee, Apis mellifera, worker longevity

Cite this dataset

Brown, Andrew et al. (2024). The more the better: Fatty acids are predictive markers of honey bee, Apis mellifera, worker longevity [Dataset]. Dryad. https://doi.org/10.5061/dryad.tmpg4f529

Abstract

Fatty acids (FA), stemming from nutrition, form triglycerides that are key components for insect energy reserves. In managed Apis mellifera colonies, supplementary feeding is common practice, yet micronutrients and microbiota (i.e. B-vitamins and probiotics) are often neglected. Given that B-vitamins are obligate cofactors for FA metabolism, and probiotics likely play key roles as well (i.e. Lactobacillus spp. synthesize B-vitamins), understanding how they contribute to FA acquisition remains unknown. Indeed, FAs are established predictors to A. mellifera longevity, and as such, are a logical point of interest in long-lived “winter” bees, where A. mellifera colony losses typically occur. Here, in a hoarding cage trial, freshly emerged adult winter workers were exposed to antibiotics (ABX) to decouple innate benefits associated to native gut microbiota, or left unexposed to ABX (N=72 cages, N=2088 experimental workers). Subsequently, all workers were fed different diets containing either probiotics, B-vitamins, with replicate treatments given ad libitum access to pollen (mimicking real-hive scenarios) or left blank (control). At the end of the trial, a subsample (n=356) had their total FA contents analyzed using Gas Chromatography coupled to Flame Ionization Detector (GC-FID). Irrespective of dietary treatment, every worker contained all 11 identified FAs, aligning our results with a priori evidence and highlighting their underlying key roles for bee physiology and health. We show for the first time that B-vitamins alone did not improve the overall abundance of individual FAs (g), yet significant differences were associated with presence/absence of bacteria and/or access to pollen, reconfirming likely ties of microbiota aiding in nutrient breakdown of complex polysaccharides found in pollen. Finally, of clear importance, there was a positive significant correlation between total lipid content and worker longevity (+2.4 median day lifespan increase / mg of FA), thereby confirming the relevance of FAs for honey bee worker longevity.

README: The more the better: Fatty acids are predictive markers of honey bee, Apis mellifera, worker longevity

Brief description of the study

This dataset contains information from winter Apis mellifera worker bees, whom underwent a hoarding cage trial, and were subject to different dietary treatments.

At 3 time increments, worker bees from each group were sampled, and processed through GC-FID to identify and quantify their fatty acid profiles.

Description of the data and file structure

The following dataset is entitled “Brown et al Plos One 2024”, and it contains one tab with 31 tables of data:

Cage: This refers to the cage that the experimental workers were kept in. Each cage had 26 bees/cage.
Median Age: This refers to the median age for the entire treatment group.
Mean Age: This refers to the mean age for the entire treatment group.
Day: This refers to the sample time point from each treatment.  There were three total sample points: Day 7, 14, and 21.
Treatment: This refers to the dietary treatment each group was assigned.
Columns 6 – 16: These are the raw amounts of fatty acids / bee / treatment group.  The name of the fatty acid is found in the column header. The values are expressed in nanograms [ng].
Total Lipid Content Nano Grams:  This refers to the sum of columns 6-16 (see description of columns above) in order to obtain a total amount of fatty acid / bee / treatment, expressed in nanograms.
Total Lipid Content  Grams: This refers to the sum of columns 6-16 (see description of columns above) in order to obtain a total amount of fatty acid / bee / treatment, expressed in grams.
Ratio lipid to body weight: This refers to a ratio of lipids to bodyweight, by simply taking the total lipid content, and dividing it by the dry weight of each individual bee used pre-fatty acid extraction.

Brief description of the R File

This file contains all data analysis, and one simply needs to download the Excel file and follow the R code.

Columns 20– 30: These are the ratios of each fatty acid. The name of the fatty acid is found in the column header.  The values are expressed in ratios 0-1.
Sum of all ratios: This is the sum of columns 20-30, ensuring that the sum of all ratios = 1 (i.e. 100%).

Methods

The data here were collected at the Institue of Bee Health (Bern, Switzerland), in autumn 2019. Subesequent Fatty Acid (FA) analysis took place at the University of Fribourg (Fribourg, Switzerland). The data has been processed (i.e. analyzed) with the open-source software R, and the script and the corresponding data are available here for download. Please refer to the publication (materials and methods) for in-depth details about data collection, FA extraction, and data analysis.

Funding

Ricola Foundation