On sperm length mean-variance relationships

Sperm length is highly variable within ejaculates, between males, populations and across species. While theory makes strong predictions about expected mean sperm size, there is less clarity on variation in sperm, although studies have reported sperm-length variation consistent with some theoretical expectations. Typically, the coefficient of variation (CV) is used in these investigations to control for mean-variance scaling. However, a key assumption for this metric to be appropriate in controlling for mean sperm size is that the standard deviation in size scales linearly with the mean. Unfortunately, sperm-length mean-variation relationships are rarely reported making it hard to assess the validity of using CV as a way to compare mean-corrected sperm variation. Here we investigate mean-variation relationships using 19,873 sperm length measures from 54 species and find little evidence of a consistent relationship between mean sperm-length and sperm-length variation among males within sp..., , # Data from: On sperm length mean-variance relationships

Dataset DOI: [10.5061/dryad.r4xgxd2s6](10.5061/dryad.r4xgxd2s6)

## Description of the data and file structure

### Files and variables

#### File:

Hosken_et_al_Sperm_Length_Measurements.csv

**Description:** a file that contains the raw data and its original published sources
Variables: species names, male ID, sperm number, sperm length, and taxon

### Code/software

Hosken_et_al_R_code_for_analyses_and_figures.R

**Description:** file that contains an R script used in the analyses

## Access information

Data was derived from the following sources:

* Sharma, M.D., Minder, A.M., and Hosken D.J. 2013. No association between sperm competition and sperm length variation across dung flies (Scathophaga). Journal of Evolutionary Biology 26:2341-2349.
* Fitzpatrick, J.L. and Baer, B. 2011. Polyandry reduces sperm length variation in social insects. Evolution 65:306-3012.

Fitzpatrick, J.L,. Garcia-Gonzales F., and Evans, J.P. 201...,