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Benefits of extra-pair mating may depend on environmental conditions-an experimental study in the blue tit (Cyanistes caeruleus).

Arct A, Drobniak SM, Podmokła E, Gustafson L, Cichoń M - Behav. Ecol. Sociobiol. (Print) (2013)

Bottom Line: This strategy may considerably improve reproductive success of males, but female benefits from extra-pair matings still remain unclear and empirical evidence is scarce.This may be because genetic benefits of extra-pair mating are not always revealed.We found that extra-pair young exhibited a higher response to phytohemagglutinin in comparison to within-pair young, but this was only observed among nestlings from experimentally enlarged broods.

View Article: PubMed Central - PubMed

Affiliation: Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland.

ABSTRACT
Extra-pair mating constitutes a relatively common reproductive strategy in many socially monogamous bird species. This strategy may considerably improve reproductive success of males, but female benefits from extra-pair matings still remain unclear and empirical evidence is scarce. This may be because genetic benefits of extra-pair mating are not always revealed. It is possible that they are shown only in unfavourable environmental conditions and hence problems arise with detecting differences between within- and extra-pair offspring whose performance is measured under favourable conditions. In order to test this prediction, we manipulated environmental conditions by altering brood sizes of blue tits and compared phenotypic characteristics of within- and extra-pair offspring in mixed-paternity broods. We found that extra-pair young exhibited a higher response to phytohemagglutinin in comparison to within-pair young, but this was only observed among nestlings from experimentally enlarged broods. These results indicate that genetic benefits may interact with the environment, and thus benefits of extra-pair mating are likely to become visible only when conditions are relatively unfavourable.

No MeSH data available.


Related in: MedlinePlus

The body mass of within-pair offspring (WPO solid line) and extra-pair offspring (EPO dashed line) in the 3 years of study. Results of post hoc analyses (linear mixed model, see “Material and methods” section for details on statistics). Least squared means with standard errors are shown. Line with asterisk connects significantly different groups (p < 0.05)
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Fig2: The body mass of within-pair offspring (WPO solid line) and extra-pair offspring (EPO dashed line) in the 3 years of study. Results of post hoc analyses (linear mixed model, see “Material and methods” section for details on statistics). Least squared means with standard errors are shown. Line with asterisk connects significantly different groups (p < 0.05)

Mentions: The proportion of extra-pair young in mixed paternity broods did not differ between years (χ22 = 0.88, p = 0.644), sexes (χ12 = 0.87, p = 0.768) and experimental groups (χ12 = 1.97, p = 0.161). We found a significant interaction between experimental treatment and paternity in the analyses of the cell-mediated immune response (Table 1; Fig. 1). The comparisons performed within experimental groups revealed that extra-pair young had greater immune responses than within-pair young among enlarged broods (F1, 108 = 5.42, p = 0.022), while no difference between extra-pair and within-pair young was found among control broods (F1, 106 = 1.13, p = 0.290; Fig. 1). Body mass on day 14 was affected by an interaction between paternity and year. To explore this relationship further, we performed additional analyses separately for each year. Extra-pair young had a lower body mass than within-pair young in 2011 while non-significant differences were observed in 2009 and 2010 (Fig. 2). Extra-pair young did not differ from within-pair young in terms of tarsus length on day 14. More importantly, the interaction between experimental treatment and paternity appeared non-significant for body mass and tarsus length (Table 1).Table 1


Benefits of extra-pair mating may depend on environmental conditions-an experimental study in the blue tit (Cyanistes caeruleus).

Arct A, Drobniak SM, Podmokła E, Gustafson L, Cichoń M - Behav. Ecol. Sociobiol. (Print) (2013)

The body mass of within-pair offspring (WPO solid line) and extra-pair offspring (EPO dashed line) in the 3 years of study. Results of post hoc analyses (linear mixed model, see “Material and methods” section for details on statistics). Least squared means with standard errors are shown. Line with asterisk connects significantly different groups (p < 0.05)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3824578&req=5

Fig2: The body mass of within-pair offspring (WPO solid line) and extra-pair offspring (EPO dashed line) in the 3 years of study. Results of post hoc analyses (linear mixed model, see “Material and methods” section for details on statistics). Least squared means with standard errors are shown. Line with asterisk connects significantly different groups (p < 0.05)
Mentions: The proportion of extra-pair young in mixed paternity broods did not differ between years (χ22 = 0.88, p = 0.644), sexes (χ12 = 0.87, p = 0.768) and experimental groups (χ12 = 1.97, p = 0.161). We found a significant interaction between experimental treatment and paternity in the analyses of the cell-mediated immune response (Table 1; Fig. 1). The comparisons performed within experimental groups revealed that extra-pair young had greater immune responses than within-pair young among enlarged broods (F1, 108 = 5.42, p = 0.022), while no difference between extra-pair and within-pair young was found among control broods (F1, 106 = 1.13, p = 0.290; Fig. 1). Body mass on day 14 was affected by an interaction between paternity and year. To explore this relationship further, we performed additional analyses separately for each year. Extra-pair young had a lower body mass than within-pair young in 2011 while non-significant differences were observed in 2009 and 2010 (Fig. 2). Extra-pair young did not differ from within-pair young in terms of tarsus length on day 14. More importantly, the interaction between experimental treatment and paternity appeared non-significant for body mass and tarsus length (Table 1).Table 1

Bottom Line: This strategy may considerably improve reproductive success of males, but female benefits from extra-pair matings still remain unclear and empirical evidence is scarce.This may be because genetic benefits of extra-pair mating are not always revealed.We found that extra-pair young exhibited a higher response to phytohemagglutinin in comparison to within-pair young, but this was only observed among nestlings from experimentally enlarged broods.

View Article: PubMed Central - PubMed

Affiliation: Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland.

ABSTRACT
Extra-pair mating constitutes a relatively common reproductive strategy in many socially monogamous bird species. This strategy may considerably improve reproductive success of males, but female benefits from extra-pair matings still remain unclear and empirical evidence is scarce. This may be because genetic benefits of extra-pair mating are not always revealed. It is possible that they are shown only in unfavourable environmental conditions and hence problems arise with detecting differences between within- and extra-pair offspring whose performance is measured under favourable conditions. In order to test this prediction, we manipulated environmental conditions by altering brood sizes of blue tits and compared phenotypic characteristics of within- and extra-pair offspring in mixed-paternity broods. We found that extra-pair young exhibited a higher response to phytohemagglutinin in comparison to within-pair young, but this was only observed among nestlings from experimentally enlarged broods. These results indicate that genetic benefits may interact with the environment, and thus benefits of extra-pair mating are likely to become visible only when conditions are relatively unfavourable.

No MeSH data available.


Related in: MedlinePlus