ORIGINAL PAPER Females prefer males with superior fighting abilities but avoid sexually harassing winners when eavesdropping on male fights David Bierbach & Vanessa Sassmannshausen & Bruno Streit & Lenin Arias-Rodriguez & Martin Plath Received: 8 August 2012 / Revised: 17 January 2013 / Accepted: 17 January 2013 / Published online: 31 January 2013 # Springer-Verlag Berlin Heidelberg 2013 Abstract Selection imposed by male competition (intrasex- ual selection) and female choice (intersexual selection) can be con- or discordant. Specifically, females may or may not prefer mating with dominant males, and direct costs of inter- acting with dominant (and possibly more harassing) males have been suggested to explain avoidance of dominant males. Here, we exemplify that inter- and intrasexual selection may normally act in the same direction, but can be temporarily conflicting when social information becomes available. Using video playback techniques, we presented females of the Mexican livebearing fish Poecilia mexicana with two size- matched males and established association preferences. Half of the females could then observe the same two males fight and establish dominance, while control females saw both males side by side, but physically separated, and female preferences were subsequently re-evaluated. Females in the control group showed a significant preference for future win- ners in the subsequent testing, confirming an innate or ac- quired preference for male traits that are indicative of physical superiority, even when body size as a choice criterion is excluded. When allowed to eavesdrop on male fights, how- ever, females did not show a preference for observed winners and even decreased time spent with them relative to the control treatment in which no fight was shown. A subsequent experiment found contest winners to show elevated levels of sexual behavior, so we argue that the temporary offset of the intrinsic female preference for dominant males after having observed a fight is indeed driven by direct costs females expect from more harassing contest winners. Keywords Female choice . Social learning . Sexual conflict . Non-independent mate choice . Male competition Introduction Inter- and intrasexual selection can have very similar effects on male trait evolution; for example, both female choice and male competition typically favor traits that increase fighting abilities (Berglund et al. 1996; Qvarnström and Forsgren 1998; Hunt et al. 2009). Females can benefit from mating with dominant males through direct and indirect fitness gains (Andersson 1994; Qvarnström and Forsgren 1998) and often choose mates based on indicators of physical superiority (Morris et al. 1992; Howard et al. 1998) or social status (Baker et al. 1986; Bishop et al. 1995; Reichard et al. 2005). However, mate choice is actually a complex process that also involves the acquisition of information from the social environment (Dugatkin 1996; Westneat et al. 2000; Witte 2006; Bonnie and Earley 2007) especially in group-living individuals which choose their mat- ing partners within a communication network put together by conspecifics (McGregor and Peake 2000; Peake 2005; Earley and Dugatkin 2005). Those aggregations create situations in which by-standing individuals may extract and subsequently use information from observed interactions to refine their own mating decisions (“social eavesdropping”; Naguib et al. 2004; Dabelsteen 2005; Fitzsimmons et al. 2008; Earley 2010). Communicated by J. Frommen D. Bierbach (*) : V. Sassmannshausen : B. Streit : M. Plath Department of Ecology & Evolution, J. W. Goethe University Frankfurt, Max-von-Laue-Straße 13, 60438 Frankfurt, Germany e-mail: david.bierbach@gmx.de L. Arias-Rodriguez División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco (UJAT), C.P. 86150 Villahermosa, Tabasco, México Behav Ecol Sociobiol (2013) 67:675–683 DOI 10.1007/s00265-013-1487-8