Ectoparasite–modulated deposition of maternal androgens in great tit eggs

Tschirren, Barbara; Richner, Heinz; Schwabl, Hubert

doi:10.1098/rspb.2004.2730

Cited by 106 publications

(129 citation statements)

References 35 publications

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“…Birds hatched from eggs with experimentally elevated yolk testosterone concentrations dispersed over significantly longer distances. Moreover, in a previous study, these authors showed that female great tits transferred lower concentrations of yolk androgens into the eggs when their nest was infested with ectoparasites compared with unexposed control females [192]. These two results suggest that the deposition of low concentrations of yolk androgens into the eggs of nests with parasites might thus be a female strategy to promote philopatry of parasitized offspring and thus to increase her offspring's and thereby her own fitness.…”

Section: Hormonally Mediated Maternal Effects On Dispersal and Populamentioning

confidence: 80%

Hormonally mediated maternal effects, individual strategy and global change

Meylan¹,

Miles

Clobert

2012

Phil. Trans. R. Soc. B

101

108

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A challenge to ecologists and evolutionary biologists is predicting organismal responses to the anticipated changes to global ecosystems through climate change. Most evidence suggests that short-term global change may involve increasing occurrences of extreme events, therefore the immediate response of individuals will be determined by physiological capacities and life-history adaptations to cope with extreme environmental conditions. Here, we consider the role of hormones and maternal effects in determining the persistence of species in altered environments. Hormones, specifically steroids, are critical for patterning the behaviour and morphology of parents and their offspring. Hence, steroids have a pervasive influence on multiple aspects of the offspring phenotype over its lifespan. Stress hormones, e.g. glucocorticoids, modulate and perturb phenotypes both early in development and later into adulthood. Females exposed to abiotic stressors during reproduction may alter the phenotypes by manipulation of hormones to the embryos. Thus, hormone-mediated maternal effects, which generate phenotypic plasticity, may be one avenue for coping with global change. Variation in exposure to hormones during development influences both the propensity to disperse, which alters metapopulation dynamics, and population dynamics, by affecting either recruitment to the population or subsequent life-history characteristics of the offspring. We suggest that hormones may be an informative index to the potential for populations to adapt to changing environments.

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Section: Hormonally Mediated Maternal Effects On Dispersal and Populamentioning

confidence: 80%

Hormonally mediated maternal effects, individual strategy and global change

Meylan¹,

Miles

Clobert

2012

Phil. Trans. R. Soc. B

101

108

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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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“…This may result in Table 2 elevated levels of oestradiol in plasma, but not in the yolk of the mature oocyte, since at the time of maximal yolk deposition oestradiol production in that follicle has decreased (Johnson 2002 fig. 1, Tschirren et al 2004). Moreover, comparative analyses of the three yolk androgens in eggs of passerine birds reveal a strong correlation of 5a-DHT with testosterone, but not of testosterone with androstenedione (Schwabl et al 2007).…”

Section: Glucocorticoids and Thyroid Hormonesmentioning

confidence: 97%

“…Yolk testosterone varies with maternal parasite exposure (Tschirren et al 2004;Gil et al 2006) and influences natal dispersal distance (e.g. Tschirren et al 2007), indicating consequences for parasite-host coevolution and population genetics.…”

Section: Introduction (A)mentioning

confidence: 99%

Hormone-mediated maternal effects in birds:mechanismsmatter but what do we know of them?

Groothuis

Schwabl

2007

Phil. Trans. R. Soc. B

Self Cite

407

426

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Over the past decade, birds have proven to be excellent models to study hormone-mediated maternal effects in an evolutionary framework. Almost all these studies focus on the function of maternal steroid hormones for offspring development, but lack of knowledge about the underlying mechanisms hampers further progress. We discuss several hypotheses concerning these mechanisms, point out their relevance for ecological and evolutionary interpretations, and review the relevant data. We first examine whether maternal hormones can accumulate in the egg independently of changes in hormone concentrations in the maternal circulation. This is important for Darwinian selection and female physiological trade-offs, and possible mechanisms for hormone accumulation in the egg, which may differ among hormones, are reviewed. Although independent regulation of plasma and yolk concentrations of hormones is conceivable, the data are as yet inconclusive for ovarian hormones. Next, we discuss embryonic utilization of maternal steroids, since enzyme and receptor systems in the embryo may have coevolved with maternal effect mechanisms in the mother. We consider doseresponse relationships and action pathways of androgens and argue that these considerations may help to explain the apparent lack of interference of maternal steroids with sexual differentiation. Finally, we discuss mechanisms underlying the pleiotropic actions of maternal steroids, since linked effects may influence the coevolution of parent and offspring traits, owing to their role in the mediation of physiological trade-offs. Possible mechanisms here are interactions with other hormonal systems in the embryo. We urge endocrinologists to embark on suggested mechanistic studies and behavioural ecologists to adjust their interpretations to accommodate the current knowledge of mechanisms.

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Ectoparasite–modulated deposition of maternal androgens in great tit eggs

Cited by 106 publications

References 35 publications

Hormonally mediated maternal effects, individual strategy and global change

Hormonally mediated maternal effects, individual strategy and global change

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

Hormone-mediated maternal effects in birds:mechanismsmatter but what do we know of them?

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