Adaptive seasonal trend in brood sex ratio: test in two sister species with contrasting breeding systems

Andersson, Malte; Wallander, Johan; Oring, Lewis W.; Akst, Elaine P.; Reed, J. Michael; Fleischer, Robert C.

doi:10.1046/j.1420-9101.2003.00533.x

Cited by 51 publications

(39 citation statements)

References 45 publications

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“…Integration of complex internal mechanisms of sex determination with a contingent mechanism of sex-specific allocation of growth-affecting substances could enable not only retention and stabilization of environmentally induced effects (see §3e), but also facultative sex-specific adjustment of the effect of ovulation order on offspring morphology (e.g. Dijkstra et al 1990;Cordero et al 2001;Andersson et al 2003).…”

Section: Evidence For the Baldwin Effect's Processes (A) Environmentamentioning

confidence: 99%

Evolutionary significance of phenotypic accommodation in novel environments: an empirical test of the Baldwin effect

Badyaev

2009

Phil. Trans. R. Soc. B

164

123

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When faced with changing environments, organisms rapidly mount physiological and behavioural responses, accommodating new environmental inputs in their functioning. The ubiquity of this process contrasts with our ignorance of its evolutionary significance: whereas within-generation accommodation of novel external inputs has clear fitness consequences, current evolutionary theory cannot easily link functional importance and inheritance of novel accommodations. One hundred and twelve years ago, J. M. Baldwin, H. F. Osborn and C. L. Morgan proposed a process (later termed the Baldwin effect) by which non-heritable developmental accommodation of novel inputs, which makes an organism fit in its current environment, can become internalized in a lineage and affect the course of evolution. The defining features of this process are initial overproduction of random (with respect to fitness) developmental variation, followed by withingeneration accommodation of a subset of this variation by developmental or functional systems ('organic selection'), ensuring the organism's fit and survival. Subsequent natural selection sorts among resultant developmental variants, which, if recurrent and consistently favoured, can be inherited when existing genetic variance includes developmental components of individual modifications or when the ability to accommodate novel inputs is itself heritable. Here, I show that this process is consistent with the origin of novel adaptations during colonization of North America by the house finch. The induction of developmental variation by novel environments of this species's expanding range was followed by homeostatic channelling, phenotypic accommodation and directional cross-generational transfer of a subset of induced developmental outcomes favoured by natural selection. These results emphasize three principal points. First, contemporary novel adaptations result mostly from reorganization of existing structures that shape newly expressed variation, giving natural selection an appearance of a creative force. Second, evolutionary innovations and maintenance of adaptations are different processes. Third, both the Baldwin and parental effects are probably a transient state in an evolutionary cycle connecting initial phenotypic retention of adaptive changes and their eventual genetic determination and, thus, the origin of adaptation and evolutionary change.

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Section: Evidence For the Baldwin Effect's Processes (A) Environmentamentioning

confidence: 99%

Evolutionary significance of phenotypic accommodation in novel environments: an empirical test of the Baldwin effect

Badyaev

2009

Phil. Trans. R. Soc. B

164

123

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“…However, differences between the sexes in growth patterns, susceptibility to ectoparasites, and sensitivity to maternally transferred hormones limit the effectiveness of maternal adjustment of offspring growth (25), especially when parasite-induced maternal effects are a passive consequence of the mother's own defense (26). Modification of the sequence in which breeding females produce sons and daughters in a clutch, a widespread phenomenon in birds (27), enables both sex-specific allocation of maternal substances, even when such allocation is passive (28,29), and sex-specific modification of growth rate and duration (30)(31)(32), which is important when sexes differ in sensitivity to ectoparasites.…”

mentioning

confidence: 99%

Sex-biased maternal effects reduce ectoparasite-induced mortality in a passerine bird

Badyaev

Hamstra

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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Duration of developmental stages in animals evolves under contrasting selection pressures of age-specific mortality and growth requirements. When relative importance of these effects varies across environments, evolution of developmental periods is expected to be slow. In birds, maternal effects on egg-laying order and offspring growth, two proximate determinants of nestling period, should enable rapid adjustment of developmental periods to even widely fluctuating mortality rates. We test this hypothesis in a population of house finches (Carpodacus mexicanus) breeding under two contrasting mortality risks: (i) a nest mite-free condition when selection on offspring survival favors a longer time in the nest; and (ii) a mite infestation when selection favors a shorter nest tenure. Mites affected survival of sons more than daughters, and females breeding under mite infestation laid male eggs last and female eggs first in the clutch, thereby reducing sons' exposure to mites and associated mortality. Strong sex bias in laying order and growth patterns enabled mite-infested offspring to achieve similar fledging size, despite a shorter nest tenure, compared with mitefree conditions. In mite-infested nests, male nestlings hatched at larger sizes, completed growth earlier, and had faster initial growth compared with mite-free nests, whereas mite-infested females grew more slowly but for a longer period of time. A combination of heavily sex-biased laying order and sex differences in growth patterns lowered mite-induced mortality by >10% in both sexes. Thus, strong maternal effects can account for frequently observed, but theoretically unexpected, concordance of mortality risks and growth patterns, especially under fluctuating ecological conditions. life history ͉ logistic growth ͉ parasites ͉ sexual dimorphism

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“…Thus, mothers are expected to bias their sex ratio towards the sex that benefits most from a large body size early in the season and vice versa (Daan et al 1996;Pen et al 1999). Indeed, a number of birds have been shown to exhibit seasonal shifts in sex ratio (reviewed in Daan et al, 1996;Andersson et al 2003). However, the link between sex-specific reproductive returns and date of hatching is not very strong in birds, mainly because species with seasonal sex-ratio shifts are long-lived and fitness consequences of early environmental conditions therefore are difficult to estimate.…”

mentioning

confidence: 99%

No Seasonal Sex-Ratio Shift Despite Sex-Specific Fitness Returns of Hatching Date in a Lizard With Genotypic Sex Determination

Uller¹,

Olsson²

2006

Evolution

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Abstract. Sex allocation theory predicts that mothers should adjust their sex-specific reproductive investment in relation to the predicted fitness returns from sons versus daughters. Sex allocation theory has proved to be successful in some invertebrate taxa but data on vertebrates often fail to show the predicted shift in sex ratio or sex-specific resource investment. This is likely to be partly explained by simplistic assumptions of vertebrate life-history and mechanistic constraints, but also because the fundamental assumption of sex-specific fitness return on investment is rarely supported by empirical data. In short-lived species, the time of hatching or parturition can have a strong impact on the age and size at maturity. Thus, if selection favors adult sexual-size dimorphism, females can maximize their fitness by adjusting offspring sex over the reproductive season. We show that in mallee dragons, Ctenophorus fordi, date of hatching is positively related to female reproductive output but has little, if any, effect on male reproductive success, suggesting selection for a seasonal shift in offspring sex ratio. We used a combination of field and laboratory data collected over two years to test if female dragons adjust their sex allocation over the season to ensure an adaptive match between time of hatching and offspring sex. Contrary to our predictions, we found no effect of laying date on sex ratio, nor did we find any evidence for within-female between-clutch sex-ratio adjustment. Furthermore, there was no differential resource investment into male and female offspring within or between clutches and sex ratios did not correlate with female condition or any partner traits. Consequently, despite evidence for selection for a seasonal sex-ratio shift, female mallee dragons do not seem to exercise any control over sex determination. The results are discussed in relation to potential constraints on sex-ratio adjustment, alternative selection pressures, and the evolution of temperature-dependent sex determination.

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Adaptive seasonal trend in brood sex ratio: test in two sister species with contrasting breeding systems

Cited by 51 publications

References 45 publications

Evolutionary significance of phenotypic accommodation in novel environments: an empirical test of the Baldwin effect

Evolutionary significance of phenotypic accommodation in novel environments: an empirical test of the Baldwin effect

Sex-biased maternal effects reduce ectoparasite-induced mortality in a passerine bird

No Seasonal Sex-Ratio Shift Despite Sex-Specific Fitness Returns of Hatching Date in a Lizard With Genotypic Sex Determination

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