Title

The Adaptive Function of Masturbation in a Promiscuous African Ground Squirrel

Authors

Authors

J. M. Waterman

Comments

Authors: contact us about adding a copy of your work at STARS@ucf.edu

Abbreviated Journal Title

PLoS One

Keywords

SEXUALLY-TRANSMITTED-DISEASES; SPERM COMPETITION RISK; XERUS-INAURIS; JAPANESE MACAQUES; EJACULATE QUALITY; SIZE; ALLOCATION; CONSEQUENCES; SCIURIDAE; EVOLUTION; Multidisciplinary Sciences

Abstract

Background: Studies of animal mating systems increasingly emphasize female multiple mating and cryptic sexual selection, particularly sperm competition. Males under intense sperm competition may manipulate sperm quantity and quality through masturbation, which could waste sperm and decrease fertility. I examined the factors influencing masturbation by male Cape ground squirrels (Xerus inauris) in light of a number of functional hypotheses. Methodology: Observational data on a marked population of squirrels were collected in east-central Namibia using scan and all-occurrences sampling. Findings: Masturbation was far more frequent on days of female oestrus and mostly occurred after copulation. Masturbation rates were higher in dominant males, which copulate more, than in subordinates and increased with number of mates a female accepts. Conclusions: These results suggest that masturbation in this species was not a response to sperm competition nor a sexual outlet by subordinates that did not copulate. Instead masturbation could function as a form of genital grooming. Female Cape ground squirrels mate with up to 10 males in a 3-hr oestrus, and by masturbating after copulation males could reduce the chance of infection. Sexually transmitted infections (STIs) can profoundly affect fertility, and their consequences for mating strategies need to be examined more fully.

Journal Title

Plos One

Volume

5

Issue/Number

9

Publication Date

1-1-2010

Document Type

Article

Language

English

First Page

7

WOS Identifier

WOS:000282210700026

ISSN

1932-6203

Share

COinS