Good-genes effects in sexual selection

Abstract

The magnitude of the e¡ect of good genes as a viability bene¢t accruing to choosy females remains a controversial theoretical and empirical issue. We collected all available data from the literature to estimate the magnitude of good-genes viability e¡ects, while adjusting for sample size. The average correlation coe¤cient between male traits and o¡spring survival in 22 studies was 0.122, which di¡ered highly signi¢cantly from zero. This implies that male characters chosen by females reveal on average 1.5% of the variance in viability. The studies demonstrated considerable heterogeneity in e¡ect size; some of this heterogeneity could be accounted for by di¡erences among taxa (birds demonstrating stronger e¡ects), and by di¡erences in the degree of mating skew in the species (high skew re£ecting stronger e¡ects). Although these results suggest that viability-based sexual selection is widespread across taxa, they indicate that the e¡ect is relatively minor. Finally, there was also an e¡ect of publication year in that the more recent studies reported reduced e¡ects. This may re£ect publication biases during paradigm shifts of this debated issue, but it should also be recalled that the studies have only partly estimated the full ¢tness consequences of mate choice for o¡spring.

Sexual selection and the evolution of evolvability

“…Thus, we assume that a male's 'good genes' are 'revealed' in the trait and the female subjects use that information to select the best male. This assumption is supported by the literature on 'good genes' effects in sexual selection (M ller and Alatalo, 1999) and by the demonstration that sexual traits can reveal genetic quality (David et al, 2000;Hale et al, ms). It is also consistent with other sexual selection models (Kokko et al, 2002).…”

“…There is now evidence that female subjects can gain genetic quality benefits for their offspring when they choose to mate with ornamented male subjects (Petrie, 1994;M ller and Alatalo, 1999). This makes it even more difficult to explain how genetic variance is maintained in the preferred male trait and in any fitness-determining loci that are revealed by the trait (Ritchie, 1996).…”

Genetic linkage between a sexually selected trait and X chromosome meiotic drive

“…Alternatively, females might choose males with a trait that, due to pleiotropy or linkage, directly indicates a gene or gene region that influences offspring fitness. While evidence for good genes effects is accumulating (Møller & Alatalo 1999), the nature of the genetic benefits indicated by male ornaments remains obscure in most cases.…”

When mothers make sons sexy: maternal effects contribute to the increased sexual attractiveness of extra-pair offspring

“…Genetic benefits in the form of good or compatible genes for the offspring are still the prominent hypothesis for why females engage in extra-pair matings [3][4][5][6] (but see [7][8][9][10] for alternative explanations such as sexual conflict). In line with this hypothesis, a growing number of studies have demonstrated that extra-pair offspring (EPO) are superior to their within-pair half-sibs in a number of fitness-related traits [11 -16].…”