Title

Structure And Allometry Of Genitalia In Males And Females Of A Social African Ground Squirrel With High Polygynandry

Keywords

Allometry; Genitalia; Polygynandry; Sexual selection

Abstract

The few studies that have looked at genital allometry in mammals have typically shown a positively allometric relationship with body size and high coefficients of variation. Cryptic female choice, sexual conflict or sperm competition are mechanisms underlying genital evolution and as these are not mutually exclusive, they are often difficult to disentangle. In addition, these mechanisms are affected by both male and female social structure and/or mating strategies and, as such, pre- and post-copulatory behaviours have been shown to alter selection on genitalia. We examined genital traits and allometry in a polygynandrous and social ground squirrel Xerus inauris. We found that male testes are positively allometric and account for 1.5% of their body weight, one of the highest percentages known for sciurids. The penis, at 42.4% of head/body length, was isometric while the female reproductive tract, 22.4% head/body length, demonstrated no such relationship. Based on the allometric relationships of both males and females presented here, in conjunction with high levels of competition for females and lack of male aggression and territoriality, we suggest that sperm competition is the most likely mechanism for the evolution of the extremely large genitalia in this species. © 2008 The Authors.

Publication Date

8-1-2008

Publication Title

Journal of Zoology

Volume

275

Issue

4

Number of Pages

375-380

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1111/j.1469-7998.2008.00449.x

Socpus ID

48249157933 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/48249157933

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