Brood sex ratio adjustment in collared flycatchers (Ficedula albicollis): results differ between populations

Rosivall, Balázs; Török, János; Hasselquist, Dennis; Bensch, Staffan

doi:10.1007/s00265-004-0796-3

Cited by 57 publications

(51 citation statements)

References 40 publications

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“…DiVerences in mean androgen levels between Wrst and replacement clutches may be a consequence of seasonal variation in brood sex ratio, which has been reported for several bird species (e.g. Daan et al 1996;Lessells et al 1996;Rosivall et al 2004). Although maternal yolk androgens do not seem to inXuence genetic sex determination in birds (Pilz et al 2005; see also Groothuis et al 2005b for a review on this topic), male and female eggs may diVer in the amount of yolk androgens they contain (Müller et al 2002).…”

Section: Yolk Androgen Levels In Wrst and Replacement Clutchesmentioning

confidence: 95%

Maternal androgens in the pied flycatcher: timing of breeding and within-female consistency

2007

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Maternal hormones can have substantial phenotypic effects in the progeny of many vertebrates. It has been proposed that mothers adaptively adjust hormone levels experienced by particular young to optimize their reproductive output. In birds, systematic variation in egg hormone levels has been related to different female reproductive strategies. Because in many bird species prospects of the offspring change seasonally and with brood number, strategic adjustment of yolk androgen levels would be expected. To test this idea, we induced pied flycatcher (Ficedula hypoleuca) females to nest twice during the same season by removing their first clutches shortly after clutch completion. We collected eggs of first and replacement clutches to measure yolk concentrations of androstenedione (A4) and testosterone (T) and captured the females that laid these clutches for phenotypic measurements. Although average egg androgen levels were remarkably consistent within females, hormone patterns differed considerably between first and replacement clutches. Eggs of replacement clutches were heavier with larger yolks compared to first clutches, but they contained on average lower levels of androgens. Within clutches, androgen concentration increased over the laying sequence in the first clutch, but decreased or remained more constant over the laying sequence in the replacement clutch. Mean yolk T, but not A4 levels, were negatively associated with laying date for both breeding attempts. Moreover, females in good body condition produced eggs containing lower levels of androgens than females in poor condition. Our results are consistent with the idea that differences in yolk androgen levels may be one mechanism underlying seasonal variation in reproductive success and it is possible that changes in egg androgen patterns may reflect a change in female reproductive strategy. High within-female consistency also highlights the possibility that there may be some underlying genetic variation in yolk androgen levels.

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Section: Yolk Androgen Levels In Wrst and Replacement Clutchesmentioning

confidence: 95%

Maternal androgens in the pied flycatcher: timing of breeding and within-female consistency

2007

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“…Other studies, however, have reported mixed (Radford & Blakey, 2000;Griffith et al, 2003;Korsten et al, 2006) or negative results (Grindstaff et al, 2001;Leech et al, 2001;Rosivall et al, 2004;Ferree, 2007). Most of these previous studies have concentrated on the physical traits of males, and behavioral sexual traits such as courtship songs have received less attention.…”

Section: Introductionmentioning

confidence: 99%

Differential allocation in relation to mate song quality in the Bengalese finch

Soma

Okanoya

2013

Behav

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Postmating sexual selection plays an important part in the evolution of secondary sexual characters. Based on differential allocation theory that predicts biased reproductive investment of females depending on the attractiveness of mates, a number of previous studies have shown that egg production is related in various ways to ornamental sexual traits of males, but evidence for behavioral sexual traits is less abundant. In this study we examine such maternal effects in relation to birdsong.Because the Bengalese finch is a monomorphic songbird, courtship song serves a key role in mate choice. To take into account individual female differences in egg production performance, we sequentially paired naïve, captive, female Bengalese finches to two different males, and investigated if their reproductive investment (clutch size, egg mass and hatchling sex ratio) was related to the song traits of their mates. We found that clutch size and egg mass were highly repeatable within individual females while sex ratio was not. Despite the inflexibility of egg mass within each female, egg mass increased when females were mated to males with longer songs. In addition, we found a non-significant weak tendency toward male-biased sex ratio in relation to longer song duration of mates. Our findings suggest that females mated to better mates adjusted their reproductive investment by producing heavier eggs and possibly offspring of the more costly sex.

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“…Yet, although relatively straightforward in theory, compelling empirical evidence for adaptive sex allocation in vertebrates remains elusive and often contradictory [3,4]. For example, despite a few striking examples of strategic sex-ratio adjustment [5][6][7], a large number of studies have found no evidence [8,9], and others suggest that biases in offspring sex ratios are not consistent within species or populations [10,11] or across years [12,13]. However, relatively few studies have attempted to investigate the sex-specific fitness costs and benefits to females (reviewed in [3,4,14]), and thus the net benefits to be gained from strategic sex ratio adjustment are often unclear or unknown.…”

Section: Introductionmentioning

confidence: 99%

Mothers adjust offspring sex to match the quality of the rearing environment

Pryke

Rollins

2012

Proc. R. Soc. B.

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Theory predicts that mothers should adjust offspring sex ratios when the expected fitness gains or rearing costs differ between sons and daughters. Recent empirical work has linked biased offspring sex ratios to environmental quality via changes in relative maternal condition. It is unclear, however, whether females can manipulate offspring sex ratios in response to environmental quality alone (i.e. independent of maternal condition). We used a balanced within-female experimental design (i.e. females bred on both low-and high-quality diets) to show that female parrot finches (Erythrura trichroa) manipulate primary offspring sex ratios to the quality of the rearing environment, and not to their own body condition and health. Individual females produced an unbiased sex ratio on high-quality diets, but over-produced sons in poor dietary conditions, even though they maintained similar condition between diet treatments. Despite the lack of sexual size dimorphism, such sex ratio adjustment is in line with predictions from sex allocation theory because nutritionally stressed foster sons were healthier, grew faster and were more likely to survive than daughters. These findings suggest that mothers may adaptively adjust offspring sex ratios to optimally match their offspring to the expected quality of the rearing environment.

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Brood sex ratio adjustment in collared flycatchers (Ficedula albicollis): results differ between populations

Cited by 57 publications

References 40 publications

Maternal androgens in the pied flycatcher: timing of breeding and within-female consistency

Maternal androgens in the pied flycatcher: timing of breeding and within-female consistency

Differential allocation in relation to mate song quality in the Bengalese finch

Mothers adjust offspring sex to match the quality of the rearing environment

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