Interfemale variation in egg yolk androgen allocation in the European starling: do high-quality females invest more?

Pilz, Kevin M.; Smith, Henrik G.; Sandell, Maria I.; Schwabl, Hubert

doi:10.1006/anbe.2003.2094

Cited by 120 publications

(110 citation statements)

References 42 publications

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“…Yet, as the average hormone levels measured in this study were very similar to values for starlings reported elsewhere (e.g., Lipar, 2001;Pilz et al, 2003;Pilz & Smith, 2004), we have no reason to suspect that the measurements are inaccurate and, therefore, obscuring strong breeding density effects. However, even though hormone levels in Pilz & Smith (2004) are expressed in a different way and were not related to the same parameters as in our study, the observed effects of social density in both studies are quite comparable in magnitude.…”

Section: Density-dependent Effectssupporting

confidence: 82%

Maternal yolk androgens in European starlings: affected by social environment or individual traits of the mother?

Eising¹,

Pavlova²,

Groothuis³

et al. 2008

Behav

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SummarySocial competition among female birds has been shown to positively affect yolk androgen levels, perhaps providing a mechanism to communicate environmental conditions to offspring. Whether this relationship is due to social density or to differences among mothers that breed in different social situations is unclear. We manipulated breeding density to test these alternative explanations. Yolk androgens were measured in clutches of European starlings, Sturnus vulgaris, breeding in consecutive years in outdoor aviaries of different sizes and with varying numbers of breeding pairs. Testosterone (T) levels increased significantly with increasing density. Dihydrotestosterone (DHT) levels increased with the number of nest boxes available. The number of nest boxes monopolized by a breeding male negatively affected androstenedione (A4) levels, positively affected DHT levels and did not affect T levels. Other factors related to social interactions or competition among females (including polygyny) did not influence yolk hormone levels. Within-female yolk androgen levels were highly consistent over two consecutive years even though females were breeding in opposite breeding densities during each year, suggesting that individual characteristics are important determinants of variation in maternal androgen allocation in addition to potential effects of environmental conditions. This within-female consistency of yolk androgen levels across years has important implications.

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Section: Density-dependent Effectssupporting

confidence: 82%

Maternal yolk androgens in European starlings: affected by social environment or individual traits of the mother?

Eising¹,

Pavlova²,

Groothuis³

et al. 2008

Behav

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“…Even if within-clutch variation in hormone deposition would have occurred in some individuals of our study population, the third egg would still represent the medium concentration of the whole clutch, as long as the pattern of within-clutch variation is linear (as found in many studied species with significant within-clutch variation, e.g. Reed and Vleck, 2001;Groothuis and Schwabl, 2002;Pilz et al, 2003;Tschirren et al, 2004).…”

Section: The Cross-fostering Experimentsmentioning

confidence: 94%

“…In most species studied so far, including the collared flycatcher and its sister species the pied flycatcher (Ficedula hypoleuca), the between-clutch variation in yolk androgen levels is higher than the within-clutch variation (e.g. Reed and Vleck, 2001;Groothuis and Schwabl, 2002;Pilz et al, 2003;Tschirren et al, 2004;Michl et al, 2005;Müller et al, 2007b, Tobler et al, 2007T. Laaksonen, unpubl.…”

Section: The Cross-fostering Experimentsmentioning

confidence: 99%

Yolk androgens do not appear to mediate sexual conflict over parental investment in the collared flycatcher Ficedula albicollis

Ruuskanen

Tschirren

Pitala

et al. 2009

Hormones and Behavior

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Yolk androgens do not appear to mediate sexual conflict over parental investment in the collared flycatcher Ficedula albicollis Ruuskanen, Suvi; Doligez, Blandine; Tschirren, Barbara; Pitala, Natalia; Gustafsson, Lars; Groothuis, Ton G. G.; Laaksonen, Toni Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Males and females are in conflict over parental care, as it would be favourable for one parent to shift labour to the other. Yolk hormones may offer a mechanism through which female birds could influence offspring traits in ways that increase the relative investment by the male. We studied the role of yolk androgens in mediating sexual conflict over parental care in the collared flycatcher (Ficedula albicollis). In a cross-fostering experiment, the male's proportion of total feeding visits increased with increasing androgen levels in the foster eggs. This could suggest that sexual conflict over parental care may be influenced by the female's differential allocation of yolk androgens or a maternal effect associated with yolk androgens. However, when we experimentally elevated yolk androgen levels, male feeding rates did not differ between control and androgen-manipulated nests. This suggests that other egg components correlated with yolk androgen levels, rather than yolk androgen levels per se, may influence male parental effort. In conclusion, yolk androgens per se do not appear to mediate sexual conflict over parental investment in the collared flycatcher.

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“…These opposing costs and benefits indicate that the optimal allocation of maternal yolk androgens into the eggs will depend on current or future environmental or social conditions. Indeed, it is well documented that factors such as breeding density (Schwabl 1997;Reed and Vleck 2001;Groothuis and Schwabl 2002;Mazuc et al 2003;Pilz and Smith 2004), timing of breeding (Schwabl 1996;Bowden et al 2000;Pilz et al 2003;Müller et al 2004), food abundance (Verboven et al 2003;Gasparini et al 2007;Warner et al 2007), partner attractiveness (Gil et al 1999(Gil et al , 2004Tanvez et al 2004;Loyau et al 2007;Kingma et al 2008), or parasitism (Tschirren et al 2004) influence maternal yolk androgen deposition.…”

Section: Introductionmentioning

confidence: 99%

Heritable Variation in Maternal Yolk Hormone Transfer in a Wild Bird Population

Tschirren¹,

Sendecka²,

Groothuis³

et al. 2009

The American Naturalist

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Differential reproductive investment by the mother can critically influence offspring development and phenotype, and strong selection is therefore expected to act on such maternal effects. Although a genetic basis is a prerequisite for phenotypic traits to respond to selection and thus to evolve, we still know very little about the extent of heritable variation in maternal effects in natural populations. Here, we present the first estimates of intrafemale repeatability across breeding seasons and estimates of heritability of hormonemediated maternal effects in a wild population of collared flycatchers (Ficedula albicollis). We found that maternal yolk testosterone (T) concentrations, yolk mass, and egg mass were moderately to highly repeatable within females across years, whereas intrafemale consistency of maternal yolk androstenedione (A4) deposition was low yet statistically significant. Furthermore, maternal yolk T transfer, yolk mass, and egg mass were significantly heritable, whereas yolk A4 transfer was not. These results strongly suggest that two major maternal yolk androgens are differentially regulated by genes and the environment. Selection on heritable variation in maternal yolk T deposition has the potential to shape the rate and direction of phenotypic change in offspring traits and can thereby accelerate or impede the response to selection in natural populations.

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Interfemale variation in egg yolk androgen allocation in the European starling: do high-quality females invest more?

Cited by 120 publications

References 42 publications

Maternal yolk androgens in European starlings: affected by social environment or individual traits of the mother?

Maternal yolk androgens in European starlings: affected by social environment or individual traits of the mother?

Yolk androgens do not appear to mediate sexual conflict over parental investment in the collared flycatcher Ficedula albicollis

Heritable Variation in Maternal Yolk Hormone Transfer in a Wild Bird Population

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