Limits...
Yolk hormones and sexual conflict over parental investment in the pied flycatcher.

Laaksonen T, Adamczyk F, Ahola M, Möstl E, Lessells CK - Behav. Ecol. Sociobiol. (Print) (2010)

Bottom Line: Females did not succeed in manipulating male effort using yolk androgens, since there was no relationship between the division of parental care within a pair and either original or foster egg androgen levels.The proportion of feeding visits by the male was higher when the male was old (55%) than when he was young (45%) and females laid eggs with higher androgen levels when mated with a young male.Young males did not exhibit any responses to yolk androgen levels either, which indicates that females cannot exploit their effort more than that of old males.

View Article: PubMed Central - PubMed

ABSTRACT
Female birds might be able to manipulate the parental effort of their male partner through elevated transfer of hormones to the eggs, since these hormones affect many chick traits that males might use as cues for adjusting the level of their investment. We experimentally studied whether female pied flycatchers Ficedula hypoleuca could manipulate male investment via yolk androgens. There is much more variation in yolk androgen levels between females than within clutches, and in order to change the androgen levels of the eggs, we swapped whole clutches between nests. To estimate the androgen levels of the clutch, we measured the androgen content of a single egg per clutch. Females did not succeed in manipulating male effort using yolk androgens, since there was no relationship between the division of parental care within a pair and either original or foster egg androgen levels. One of these relationships should have occurred if females were manipulating males. The proportion of feeding visits by the male was higher when the male was old (55%) than when he was young (45%) and females laid eggs with higher androgen levels when mated with a young male. Young males did not exhibit any responses to yolk androgen levels either, which indicates that females cannot exploit their effort more than that of old males. We suggest that females may allocate yolk androgens to adjust the growth trajectories of the chicks to poor growing conditions when mated with young males that are poor providers or occupying a poor territory.

No MeSH data available.


Related in: MedlinePlus

Difference in the androgen levels (PC 1) in the eggs laid by partners of 1-year-old and older male pied flycatchers (mean ± s.e.). Sample size (one egg (the fourth) per clutch) is indicated above the bars. The corresponding mean (± s.e.) concentrations of the two hormones separately were: 124.89 ± 12.44 ng/g A4 and 15.76 ± 1.23 ng/g T for 1-year-old males; and 98.28 ± 6.03 ng/g A4 and 13.08 ± 0.83 ng/g T for older males (F1,77 = 3.47, p = 0.067 for A4, and F1,77 = 3.49, p = 0.066 for T)
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3197946&req=5

Fig2: Difference in the androgen levels (PC 1) in the eggs laid by partners of 1-year-old and older male pied flycatchers (mean ± s.e.). Sample size (one egg (the fourth) per clutch) is indicated above the bars. The corresponding mean (± s.e.) concentrations of the two hormones separately were: 124.89 ± 12.44 ng/g A4 and 15.76 ± 1.23 ng/g T for 1-year-old males; and 98.28 ± 6.03 ng/g A4 and 13.08 ± 0.83 ng/g T for older males (F1,77 = 3.47, p = 0.067 for A4, and F1,77 = 3.49, p = 0.066 for T)

Mentions: The concentrations of the two hormones (A4 and T) were positively correlated (r = 0.58, P < 0.0001, N = 95) and thus could not be considered independent from each other in the analyses. We therefore performed a principal component analysis on them and used the first principal component (PC1) as a measure of androgen concentration in the analyses. PC1 captured 79% of the total variation and was highly correlated with the concentrations of both hormones (A4: r = 0.89, P < 0.0001, N = 95; T: r = 0.89, P < 0.0001, N = 95). Increasing values of PC1 indicate increasing values of both hormones. Although we have based our interpretations solely on PC1 in this paper, we have also given details of the results for A4 and T separately (Fig. 2). We have done this in order to make these data useful and available to future researchers.Fig. 2


Yolk hormones and sexual conflict over parental investment in the pied flycatcher.

Laaksonen T, Adamczyk F, Ahola M, Möstl E, Lessells CK - Behav. Ecol. Sociobiol. (Print) (2010)

Difference in the androgen levels (PC 1) in the eggs laid by partners of 1-year-old and older male pied flycatchers (mean ± s.e.). Sample size (one egg (the fourth) per clutch) is indicated above the bars. The corresponding mean (± s.e.) concentrations of the two hormones separately were: 124.89 ± 12.44 ng/g A4 and 15.76 ± 1.23 ng/g T for 1-year-old males; and 98.28 ± 6.03 ng/g A4 and 13.08 ± 0.83 ng/g T for older males (F1,77 = 3.47, p = 0.067 for A4, and F1,77 = 3.49, p = 0.066 for T)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3197946&req=5

Fig2: Difference in the androgen levels (PC 1) in the eggs laid by partners of 1-year-old and older male pied flycatchers (mean ± s.e.). Sample size (one egg (the fourth) per clutch) is indicated above the bars. The corresponding mean (± s.e.) concentrations of the two hormones separately were: 124.89 ± 12.44 ng/g A4 and 15.76 ± 1.23 ng/g T for 1-year-old males; and 98.28 ± 6.03 ng/g A4 and 13.08 ± 0.83 ng/g T for older males (F1,77 = 3.47, p = 0.067 for A4, and F1,77 = 3.49, p = 0.066 for T)
Mentions: The concentrations of the two hormones (A4 and T) were positively correlated (r = 0.58, P < 0.0001, N = 95) and thus could not be considered independent from each other in the analyses. We therefore performed a principal component analysis on them and used the first principal component (PC1) as a measure of androgen concentration in the analyses. PC1 captured 79% of the total variation and was highly correlated with the concentrations of both hormones (A4: r = 0.89, P < 0.0001, N = 95; T: r = 0.89, P < 0.0001, N = 95). Increasing values of PC1 indicate increasing values of both hormones. Although we have based our interpretations solely on PC1 in this paper, we have also given details of the results for A4 and T separately (Fig. 2). We have done this in order to make these data useful and available to future researchers.Fig. 2

Bottom Line: Females did not succeed in manipulating male effort using yolk androgens, since there was no relationship between the division of parental care within a pair and either original or foster egg androgen levels.The proportion of feeding visits by the male was higher when the male was old (55%) than when he was young (45%) and females laid eggs with higher androgen levels when mated with a young male.Young males did not exhibit any responses to yolk androgen levels either, which indicates that females cannot exploit their effort more than that of old males.

View Article: PubMed Central - PubMed

ABSTRACT
Female birds might be able to manipulate the parental effort of their male partner through elevated transfer of hormones to the eggs, since these hormones affect many chick traits that males might use as cues for adjusting the level of their investment. We experimentally studied whether female pied flycatchers Ficedula hypoleuca could manipulate male investment via yolk androgens. There is much more variation in yolk androgen levels between females than within clutches, and in order to change the androgen levels of the eggs, we swapped whole clutches between nests. To estimate the androgen levels of the clutch, we measured the androgen content of a single egg per clutch. Females did not succeed in manipulating male effort using yolk androgens, since there was no relationship between the division of parental care within a pair and either original or foster egg androgen levels. One of these relationships should have occurred if females were manipulating males. The proportion of feeding visits by the male was higher when the male was old (55%) than when he was young (45%) and females laid eggs with higher androgen levels when mated with a young male. Young males did not exhibit any responses to yolk androgen levels either, which indicates that females cannot exploit their effort more than that of old males. We suggest that females may allocate yolk androgens to adjust the growth trajectories of the chicks to poor growing conditions when mated with young males that are poor providers or occupying a poor territory.

No MeSH data available.


Related in: MedlinePlus