Explosive eversion and functional morphology of the duck penis supports sexual conflict in waterfowl genitalia

Coevolution of male and female genitalia in waterfowl has been hypothesized to occur through sexual conflict. This hypothesis raises questions about the functional morphology of the waterfowl penis and the mechanics of copulation in waterfowl, which are poorly understood. We used high-speed video of phallus eversion and histology to describe for the first time the functional morphology of the avian penis. Eversion of the 20 cm muscovy duck penis is explosive, taking an average of 0.36 s, and achieving a maximum velocity of 1.6 m s(-1). The collagen matrix of the penis is very thin and not arranged in an axial-orthogonal array, resulting in a penis that is flexible when erect. To test the hypothesis that female genital novelties make intromission difficult during forced copulations, we investigated penile eversion into glass tubes that presented different mechanical challenges to eversion. Eversion occurred successfully in a straight tube and a counterclockwise spiral tube that matched the chirality of the waterfowl penis, but eversion was significantly less successful into glass tubes with a clockwise spiral or a 135 degrees bend, which mimicked female vaginal geometry. Our results support the hypothesis that duck vaginal complexity functions to exclude the penis during forced copulations, and coevolved with the waterfowl penis via antagonistic sexual conflict.

Medienart:

E-Artikel

Erscheinungsjahr:

2010

Erschienen:

2010

Enthalten in:

Zur Gesamtaufnahme - volume:277

Enthalten in:

Proceedings. Biological sciences - 277(2010), 1686 vom: 07. Mai, Seite 1309-14

Sprache:

Englisch

Beteiligte Personen:

Brennan, Patricia L R [VerfasserIn]
Clark, Christopher J [VerfasserIn]
Prum, Richard O [VerfasserIn]

Links:

Volltext

Themen:

Journal Article
Research Support, Non-U.S. Gov't

Anmerkungen:

Date Completed 03.08.2010

Date Revised 20.10.2021

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1098/rspb.2009.2139

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM193959348