title: Audience effects in the Atlantic molly (Poecilia mexicana)-prudent male mate choice in response to perceived sperm competition risk?
abstract: BACKGROUND
  Multidirectional interactions in social networks can have a profound effect on mate choice behavior; e.g., Poecilia mexicana males show weaker expression of mating preferences when being observed by a rival. This may be an adaptation to reduce sperm competition risk, which arises because commonly preferred female phenotypes will receive attention also from surrounding males, and/or because other males can copy the focal male's mate choice. Do P. mexicana males indeed respond to perceived sperm competition risk? We gave males a choice between two females and repeated the tests under one of the following conditions: (1) an empty transparent cylinder was presented (control); (2) another ("audience") male inside the cylinder observed the focal male throughout the 2nd part, or (3) the audience male was presented only before the tests, but could not eavesdrop during the actual choice tests (non-specific sperm competition risk treatments); (4) the focal male could see a rival male interact sexually with the previously preferred, or (5) with the non-preferred female before the 2nd part of the tests (specific sperm competition risk treatments).
  
  
  RESULTS
  The strength of individual male preferences declined slightly also during the control treatment (1). However, this decrease was more than two-fold stronger in audience treatment (2), i.e., with non-specific sperm competition risk including the possibility for visual eavesdropping by the audience male. No audience effect was found in treatments (3) and (5), but a weak effect was also observed when the focal male had seen the previously preferred female sexually interact with a rival male (treatment 4; specific sperm competition risk).
  
  
  CONCLUSIONS
  When comparing the two 'non-specific sperm competition risk' treatments, a very strong effect was found only when the audience male could actually observe the focal male during mate choice [treatment (2)]. This suggests that focal males indeed attempt to conceal their mating preferences so as to prevent surrounding males from copying their mate choice. When there is no potential for eavesdropping [treatment (3)], non-specific specific sperm competition risk seems to play a minor or no role. Our results also show that P. mexicana males tend to share their mating effort more equally among females when the resource value of their previously preferred mate decreases after mating with a rival male (perceived specific sperm competition risk), but this effect is comparatively weak.
authors.affiliation: Department of Ecology & Evolution, J,W, Goethe University Frankfurt, Siesmayerstrasse 70-72, D-60054 Frankfurt am Main, Germany. martin_plath@web.de.
authors.forename: Madlen
authors.initials: M
authors.lastname: Ziege
authors.forename: Kristin
authors.initials: K
authors.lastname: Mahlow
authors.forename: Carmen
authors.initials: C
authors.lastname: Hennige-Schulz
authors.forename: Claudia
authors.initials: C
authors.lastname: Kronmarck
authors.forename: Ralph
authors.initials: R
authors.lastname: Tiedemann
authors.forename: Bruno
authors.initials: B
authors.lastname: Streit
authors.forename: Martin
authors.initials: M
authors.lastname: Plath
references.citation: Nature. 2001 Jan 25;409(6819):475
references.pmid: 11206533
references.citation: Anim Behav. 1998 Mar;55(3):545-52
references.pmid: 9514666
references.citation: Curr Biol. 2008 Aug 5;18(15):1138-41
references.pmid: 18674912
references.citation: Learn Behav. 2004 Feb;32(1):105-13
references.pmid: 15161145
references.citation: Oecologia. 2003 Sep;137(1):62-8
references.pmid: 12856201
references.citation: Behaviour. 1969;33(1):1-38
references.pmid: 5815891
references.citation: Nature. 2007 Jan 25;445(7126):429-32
references.pmid: 17251980
references.citation: Anim Behav. 2000 Mar;59(3):467-476
references.pmid: 10715168
references.citation: Am Nat. 1992 Dec;140(6):1000-9
references.pmid: 19426031
references.citation: Anim Behav. 1998 Sep;56(3):689-693
references.pmid: 9784218
references.citation: Proc Natl Acad Sci U S A. 2001 Jul 31;98(16):9177-80
references.pmid: 11459936
references.citation: Biol Lett. 2007 Feb 22;3(1):5-7
references.pmid: 17443951
references.citation: Curr Biol. 2008 Jun 3;18(11):R462-3
references.pmid: 18522813
references.citation: Nature. 2004 Jul 22;430(6998):448-51
references.pmid: 15269767
references.citation: Proc Biol Sci. 2002 May 7;269(1494):943-52
references.pmid: 12028778
references.citation: Behav Processes. 2003 May 28;63(1):53-61
references.pmid: 12763268
references.citation: Commun Integr Biol. 2008;1(2):199-203
references.pmid: 19513259
references.citation: Science. 2004 Jul 23;305(5683):487-91
references.pmid: 15273386
references.citation: Naturwissenschaften. 2003 Dec;90(12):577-82
references.pmid: 14676956
references.citation: Philos Trans R Soc Lond B Biol Sci. 2002 Nov 29;357(1427):1549-57
references.pmid: 12495512
references.citation: Commun Integr Biol. 2009 May;2(3):282-4
references.pmid: 19641752