Superior fighters make mediocre fathers in the Pacific blue-eye fish BOB B. M. WONG School of Botany and Zoology, Australian National University, Australia (Received 13 September 2002; initial acceptance 28 November 2002; final acceptance 2 August 2003; MS. number: 7464R) It is widely assumed that male competition and female choice select for elaboration of the same male traits and that fighting ability is synonymous with high quality in terms of benefits to females. Under these assumptions, females are expected to use the same traits that reflect fighting ability to choose the most dominant male, even if females are not privy to actual maleemale interactions. Few studies, however, have explicitly investigated female choice in relation to male fighting ability. I conducted experiments separating the effects of male competition and female choice in a freshwater fish, the Pacific blue-eye, Pseudomugil signifer, to test whether females prefer dominant males and whether females obtain higher egg hatching success by being choosy. When females were precluded from witnessing agonistic encounters between two potential mates, they did not appear to use traits correlated with fighting ability to choose competitively superior males. However, even when females were privy to competition, witnessing male interactions did not induce a preference for dominant individuals. Lack of preference for superior fighters may be because there was no difference in hatching success between eggs guarded by dominant and subordinate males. Instead, females appeared to prefer males that spent a greater proportion of time engaged in courtship and, in so choosing, enjoyed higher egg hatching success. These results indicate that dominant males are not necessarily more attractive than subordinates nor do the former necessarily guarantee or deliver the kind of benefits that females may seek. Ó 2004 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved. It is generally assumed that maleemale competition and female choice operate by mutually reinforcing one another and selecting for elaboration of the same male traits (Berglund et al. 1996). Signals important in a contest situation are also expected to serve as reliable cues in female choice because such traits are believed to convey accurate information about the overall condition of males as prospective mates (Candolin 1999; Berglund & Rosenqvist 2001). Indeed, superior fighting ability is often equated with high quality in terms of fitness gains to females (e.g. Bisazza et al. 1989; Montgomerie & Thornhill 1989; Alatalo et al. 1991; Kodric-Brown 1996). Because females maximize reproductive success by optimizing the quality of their mating partners (Qvarnstro ¨m & Forsgren 1998), they are assumed to benefit by mating with dominant males. Certainly, across a suite of taxa, females are purported to derive a range of direct or indirect benefits by choosing to mate with dominant males (reviewed in Berglund et al. 1996) and females of some species are known to stage or incite competition, presumably to ensure mating with the ‘best’ males (e.g. Cox & LeBoeuf 1977; Thornhill 1988; Montgomerie & Thornhill 1989; but see O’Connell & Cowlishaw 1994). One potential problem, however, is that the two processes of sexual selection are often confounded in time and space. Although winners of maleemale compe- tition often enjoy higher mating success than losers, it may be difficult to determine accurately whether this mating bias actually reflects a female preference for dominant males. Furthermore, even if females are able to assess potential suitors accurately, there is no assurance that their preferences will be realized (Jennions & Petrie 1997; Kokko et al. 2003). Males, for example, may coerce females into mating with them (reviewed in Clutton- Brock & Parker 1995) or they may deny more attractive (but socially subordinate) males from holding territories needed for breeding (Andersson et al. 2002). In these instances, competition, rather than female choice, could operate to determine mating outcomes. Mate choice in relation to male fighting ability may be less straightforward than traditionally assumed. It is be- coming increasingly apparent that females do not always prefer to mate with dominant males. In terms of optimiz- ing female fitness, mating with a superior competitor does Correspondence and present address: B. B. M. Wong, Boston University Marine Program, 7 MBL Street, Woods Hole, MA 02543, U.S.A. (email: bob.wong@anu.edu.au). 583 0003e3472/03/$30.00/0 Ó 2004 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved. ANIMAL BEHAVIOUR, 2004, 67, 583e590 doi:10.1016/j.anbehav.2003.08.015