Traits that are correlated with mating success are likely to be subject to sexual selection. In lekking species, a male's mating success can be estimated as the number of females that he copulates with. Earlier reviews of sexual selection in lekking species have been inconclusive, suggesting that different traits may be important in different species. To obtain a more complete understanding of the outcome of sexual selection in this mating system, we performed a meta-analysis in which we combined the results from different studies across a wide variety of taxa. Our aim was to synthesize available information about correlates of male mating success in lekking species. We found that behavioral traits such as male display activity, aggression rate, and lek attendance were positively correlated with male mating success. Further, territory position was negatively correlated with male mating success, such that males with territories close to the geometric center of the leks had higher mating success than other males. The size of "extravagant" traits, such as birds tails and ungulate antlers, and age were positively correlated with male mating success. Male morphology (measure of body size) and territory size showed small effects on male mating success. Our results confirm some of the suggestions put forward by earlier reviews but add more rigor to the conclusions drawn. Part of the variation across studies still remain unaccounted for. Further studies are needed to perform proper meta-analyses that can take factors like phylogeny and sexual dimorphism into account

The male lifetime lekking performance was studied, and related to inbreeding± outbreeding in a wild population of black grouse (Tetrao tetrix) in central Finland between 1989 and 1995. Inbreeding was measured as the mean heterozygosity and mean d 2 of 15 microsatellite loci. We found a signi® cantly positive relationship between mean d 2 and lifetime copulation success (LCS), while the relationship between heterozygosity and LCS was close to signi® cant. We also found that males that never obtained a lek territory had signi® cantly lower mean heterozygosity than males that were observed on a territory at least during one mating season in their life. Furthermore, among males that were successful in obtaining a lek territory, LCS and mean d 2 were highest for those males that held central territories. We suggest that inbred males have a disadvantage (or outbred males have an advantage) in the competition for territories that may explain the relationships with LCS and inbreeding. Furthermore, the fact that mean d 2 was positively correlated with LCS whereas heterozygosity was not when we restricted the analysis to territorial males, suggests that mean d 2 provides more information about levels of inbreeding± outbreeding than heterozygosity alone, and potentially highlights the effects of heterosis. To our knowledge, this is the ® rst time that measures of inbreeding and lifetime ® tness have been linked in a non-isolated population. This is important in establishing that the relationships found in previous studies are not artefacts of low gene¯ow created by limited dispersal but a general feature of wild vertebrate populations.

Good genes' models assume that females can use a signal such as mating e¡ort to assess a male's lifetime ¢tness. Inferring long-term performance from short-term behavioural observations can be unreliable, and repeated sampling may be needed for more accurate assessment of males. Additionally, if sexual advertisement is viewed as a life-history trait subject to trade-o¡s, reliable comparison of mates should yield information on all life-history components rather than on one trait value in one season. We show that in the lekking black grouse (Tetrao tetrix), a male's success is best explained by assuming that females are informed of the past history of males up to the beginning of the study (eight years). Much of this extremely lasting`memory' can be attributed to females observing long-term outcomes of male^male competition: current territory position is the only momentarily observable variable that has high power in predicting female choice, and it correlates to a male's past lekking e¡ort on a cumulative lifetime scale. We conclude that females can use territory position as a signal that conveys information of a male's lifetime performance that combines lekking e¡ort and longevity. Females may thus overcome the problem of male allocations varying in time, without the need to pay costs associated with repeated sampling.

We studied female mate sampling behaviour in lekking black grouse (Tetrao tetrix). Females mainly visited males occupying territories in the centre of the lek with relatively large territories. They were also more likely to visit males that had high attendance. The same factors were also correlated with male mating success. A multiple regression model including these factors explained more of the variance in female visits per male (52%) than in mating success (33%). The pattern of female sampling conformed with a pool comparison (best-of-n) tactic. Such a tactic is expected if the costs of sampling are low. Females of high body mass visited more males than lighter females, however, which indicates that females may vary in their search tactics and suggests that there may be search costs. The existence of costs is further suggested by the fact that if the mate from a previous year was still present, females always mated with the same male in the following year. Though search costs were not measured directly, our findings suggest that some costs are negligible (e.g. energetic exhaustion or predation) whereas others (timing of mating) may be more important.

No abstract