Reproductive output of old males is limited by seminal fluid, not sperm number
Data files
Jan 10, 2025 version files 5.11 MB
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BG.csv
7.97 KB
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gfp_f.csv
15.28 KB
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gfp_m.csv
2.35 KB
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gfp.clean.csv
17.46 KB
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latency.csv
31.73 KB
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Prominence.csv
4.86 KB
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Read_me.docx
21.12 KB
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README.docx
20.03 KB
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README.md
6.60 KB
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repeatability.xlsx
18.04 KB
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sample_sizes.xlsx
12.06 KB
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stripping_simple.Rmd
58.24 KB
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stripping-simple.html
4.78 MB
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stripping.csv
80.46 KB
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survival_population.csv
41.85 KB
Abstract
Male reproductive senescence is typically characterised by a decline in the number of sperm produced and transferred by old males, a phenomenon that may be exacerbated in polygynous species where males mate-multiply. However, males also transfer seminal fluid to females, and little is known about its role in modulating male reproductive senescence. Here, we explore the contributions of sperm and seminal fluid towards male reproductive senescence in a series of sequential matings, using Drosophila melanogaster. As expected, old males produce fewer offspring than young males. However, this pattern is not driven by sperm limitation: old males have more sperm and transfer similar numbers to females, compared to young males. Instead, females storing fewer sperm of old males compared to that of young males, over a long-term, drives male reproductive senescence. We are able to mitigate the age-related decline in male reproductive output by supplementing females with the seminal fluid of a young male, before she mates with an old male. Similarly, we alleviate the reduction in reproductive output across sequential matings by supplementing females with seminal fluid. Our findings highlight that seminal fluid, rather than sperm number, limits reproductive success in old or multiply mating males, highlighting its under-appreciated role in reproductive ageing.
README: Reproductive output of old males is limited by seminal fluid, not sperm number
Note: In the dataset, the labels for Experiment ID are contrasting the paper: in the dataset, Experiment B is actually experiment C from the paper, and experiment C in the dataset is experiment B in the paper.
https://doi.org/10.5061/dryad.mpg4f4r99
Description of the data and file structure
1. BG.csv : csv data file for plotting batemans’s gradient in R code
2. Stripping simple.rmd: R code needed to run all analysis (all data provided on OSF)
3. Stripping: data from experiments A and C on reproductive output
4. gfp_f.csv : data on sperm numbers inside females after dissection of females, to be used in R code. Also has data on the numbers of offspring produced by females over 24 hours of egg laying, in a male’s mating sequence, for experiment B.
5. gfp_m.csv : data on sperm numbers inside male SV and size of male Accessory glands from experiment B
6. latency.csv: data on male mating latency and copulation duration across three experiments
7. Prominence.csv: data on the relationship between prominence on find maxima and estimated sperm counts, to determine the most suitable prominence for counting sperm using the find maxima function
8. Repeatability.xlsx : repeatability in sperm counts data
9. Sample sizes.xlsx : sample sizes from all three experiemnts
10. Survival_population.csv : data for survival curves of males in the three lines used.
11. Stripping-simple.html: HTML output of full code
Files and variables
File: BG.csv
Description:
Variables
• ID: ID of male
• MS: Mating success
• RS: Reproductive success
• Age: Age of male
• Experiment: Experiment A B or C
• Treatment: Old or young male
File: gfp_f.csv
Description:
Variables
• Rep: Block
• Female_number: Female rank in mating sequence
• Male_ID: Male ID
• Female_ID: Female ID
• Duration: Mating duration
• Age: Male age
• F1_counts: Number of offspring produced
• Freezing: When female was frozen-immediately or after 24 hours of egg laying
• Total30: Total sperm from immediately frozen females
• SR: Sperm in seminal receptacle
• Total24: Total sperm in females frozen after 24 hours
• Fertility: Female fertility (1/0)
• Total_matings: Mating success of males
• Fertility_F1: Female fertility
File: gfp.clean.csv
Description: Data for GFP males
Variables:
• Male_ID: male ID
• Rep: Replicate/block
• Age: Old or young age groups
• N_matings: mating success of males
• Sperm_total: total sperm in male accessory glands
• AG_mean: mean accessory gland size area of males
• Squared: squared number of sperm
File: gfp_m.csv
Description: Data for GFP males
Variables
• Male_ID: Male ID
• Rep: Block
• Age: Male age
• N_matings: Mating success
• Sperm_total: Total sperm in male seminal vesicle
• AG_mean: Mean size or area of accessory glands
File: Prominence.csv
Description: Find maxima prominence setting determination
Variables
• Image_ID: Image ID
• Prominence: Prominence set on find maxima
• Count: Sperm counts for a given prominence estimated by find maxima
• Sex: Sex of individual from whom sperm was obtained (Male or female) storage
File: latency.csv
Description: Mating latency, duration, success data
Variables
• Line: GFP, sot, or dah line
• F_num: Female rank
• Male_ID: Male ID
• Latency: Mating latency
• Duration: Copulation duration
• Male_Age: Male age
File: Read_me.docx
Description: Read me document
File: sample_sizes.xlsx
Description: Final sample sizes used
Variables
• Age: old or young males
• SF: whether seminal fluid was provided with sot males or not provided
• Female_number: female rank in mating sequence
• N: Sample size
• F1:counts: average F1 counts of offspring numbers produced
• Sd: standard deviation of offspring numbers produced
• Se: standard error of offspring numbers produced
• CI: confidence interval of offspring numbers produced
• Experiment: A, B, or C (not that labels of experiments B and C are swapped compared to the paper)
• Duration: Mating duration
File: repeatability.xlsx
Description: Repeatability of find maxima and manual sperm counts on ImageJ/FIJI
Variables
Sheet 1
• ID: Image ID
• Manual_KS: manual sperm count by Krish Sanghvi using cell counter
• Fiji_threshold: counts estimated automatically using thresholding in FIJI
• Manual_tara: manual counts by Tara
• Manual_Becky: Manual counts by Becky
• Fiji_findmaxima: Automated sperm counts estimated using find maxima plugin
• Fiji_findmaxima_sharpen: automated find maxima counts on sharpened images
• Manual_KS_pixelated_czi: manual counts done by KS
Sheet 3:
• Image_ID: image ID
• Find_maxima (5000 prominence): estimated sperm counts automated using find maxima plugin
• Manual: sperm counts done manually
Sheet 2:
Notes
File: stripping.csv
Description: Offspring produced by females for experiments
Variables
• Row: Row ID
• Rep: Block
• Block: Block within experiment
• Age: Male age
• SF: Sot experiment C (sot) or dah experiment A (No)
• Treatment: Overall treatment
• Female_number: Female rank in mating sequence
• sot_duration: son of tudor male mating duration
• lag: Lag between sot and dah mating in experiment C
• Latency: dah male mating latency
• Duration: dah male copulation duration
• Total_matings: Mating success
• Male_ID: Male ID
• Female_ID: Female ID
• F1_counts: Numbers of offspring produced
• Fertility: Fertile or not
• F_num.adjusted: Mating success of male
• Prev_current_fert: Whether previous mating was fertile or not (not used in analysis)
• 0_1: Whether previous meting was infertile but next mating was fertile (not relevant)
File: stripping_simple.Rmd
Description: RMD file for analysis of data
File: survival_population.csv
Description: Survival of males from three lines used
Variables
• ID: Male ID
• Born: Male birth date
• Died: Death date
• Censor: Whether death was observed or not
• Line: sot, dah or gfp line used
• Lifespan: Lifespan of male
File: stripping-simple.html
Description: HTML R markdown file of analysis
Code/software
R studio, R v4
Access information
Other publicly accessible locations of the data:
Data was derived from the following sources:
• Open science framework
Methods
We conducted experiments and colelcted data directly through observations.