Constraints on Hatching Asynchrony and Egg Size in Pied Flycatchers

10.2307/5127 ◽  
1989 ◽  
Vol 58 (3) ◽  
pp. 837 ◽  
Author(s):  
Tore Slagsvold ◽  
Jan T. Lifjeld
Keyword(s):  
Egg Size ◽  
Hatching Asynchrony

scholarly journals Migratory constraints on yolk precursors limit yolk androgen deposition and underlie a brood reduction strategy in rockhopper penguins

2012 ◽  
Vol 8 (6) ◽  
pp. 1055-1058 ◽  
Author(s):  
Glenn T. Crossin ◽  
Maud Poisbleau ◽  
Laurent Demongin ◽  
Olivier Chastel ◽  
Tony D. Williams ◽  
...  
Keyword(s):  
Steroid Hormones ◽  
Maternal Effects ◽  
Egg Size ◽  
Hatching Asynchrony ◽  
Brood Reduction ◽  
Size Dimorphism ◽  
Reduction Strategy ◽  
Yolk Androgens ◽  
Linear Relationships ◽  
Androgen Levels

Hormonally mediated maternal effects link maternal phenotype and environmental conditions to offspring phenotype. The production of lipid-rich maternal yolk precursors may provide a mechanism by which lipophilic steroid hormones can be transported to developing yolks, thus predicting a positive correlation between yolk precursors in mothers and androgen levels in eggs. Using rockhopper penguins ( Eudyptes chrysocome ), which produce a two-egg clutch characterized by extreme egg-size dimorphism, reversed hatching asynchrony and brood-reduction, we examined correlations between circulating concentrations of the primary yolk-precursor vitellogenin (VTG) and levels of yolk androgens. Previous work in Eudyptes penguins has shown that egg-size dimorphism is the product of migratory constraints on yolk precursor production. We predicted that if yolk precursors are constrained, androgen transport to developing yolks would be similarly constrained. We reveal positive linear relationships between maternal VTG and androgens in small A-eggs but not larger B-eggs, which is consistent with a migratory constraint operating on the A-egg. Results suggest that intra-clutch variation in total yolk androgen levels depends on the production and uptake of yolk precursors. The brood reduction strategy common to Eudyptes might thus be best described as the result of a migratory constraint.

Supplemental food affects egg size but not hatching asynchrony in rollers

2012 ◽  
Vol 66 (8) ◽  
pp. 1097-1105 ◽  
Author(s):  
D. Parejo ◽  
J. M. Avilés ◽  
J. Rodríguez
Keyword(s):  
Egg Size ◽  
Hatching Asynchrony ◽  
Supplemental Food

Adaptive aspects of intraclutch egg-size variation in the High Arctic barnacle goose (Branta leucopsis)

2002 ◽  
Vol 80 (7) ◽  
pp. 1180-1188 ◽  
Author(s):  
Christiaane E Hübner ◽  
Ingunn M Tombre ◽  
Kjell E Erikstad
Keyword(s):  
Egg Size ◽  
Hatching Success ◽  
Size Variation ◽  
High Arctic ◽  
Hatching Asynchrony ◽  
Nutrient Allocation ◽  
Egg Predation ◽  
Barnacle Goose ◽  
Laying Sequence ◽  
Branta Leucopsis

The pattern of intraclutch egg-size variation in barnacle goose (Branta leucopsis) clutches and its adaptive implications was studied in Svalbard, Norway, from 1989 to 1998. Egg size was measured in relation to laying sequence, egg predation and hatching order were recorded to determine hatching success of eggs in different laying sequences, and the time when incubation started was examined. Egg size showed a rather consistent pattern, with a large second-laid egg and declining egg size for the remainder of the clutch. The first-laid egg was usually smaller than the second one, except in clutches with two and three eggs. Predation was highest for the first-laid egg, and last-laid eggs hatched last in most cases, although only one last-laid egg was abandoned. Four of six females started incubation before clutch completion. Both the "nutrient-allocation hypothesis" as well as the "early incubation start hypothesis" may contribute to explaining the expressed pattern of intraclutch egg-size variation. The fitness gains due to allocating fewer nutrients to eggs in unfavourable positions in the laying sequence may explain the small size of the first egg, whereas the multiple benefits of an early incubation start may have led to the decline in egg size later in the laying sequence as a mechanism to counteract hatching asynchrony.

scholarly journals Egg-Capping is a Cost Paid by Hosts of Interspecific Brood Parasites

The Auk ◽  
2003 ◽  
Vol 120 (3) ◽  
pp. 860-865
Author(s):  
Mark E. Hauber
Keyword(s):  
New York ◽  
Reproductive Success ◽  
Brood Parasitism ◽  
Egg Size ◽  
Molothrus Ater ◽  
Fitness Cost ◽  
Hatching Asynchrony ◽  
Brood Parasites ◽  
Interspecific Brood Parasitism ◽  
Shell Fragments

Abstract Egg-capping is the slipping of a hatched eggshell fragment over an intact shell. It is a rare phenomenon among avian species, probably because most eggs in the same clutch hatch synchronously, are similar in size, and parents typically remove debris—including shell fragments—from nests. Hatching asynchrony and egg-size differences are typically more pronounced in the context of interspecific brood parasitism, making conditions for egg-capping more likely. Indeed, egg-capping of host eggs occurred in 33% of clutches of Eastern Phoebes (Sayornis phoebe) parasitized by Brown-headed Cowbirds (Molothrus ater), always by the earlier hatched cowbird's eggshell, whereas it was not detected in nonparasitized clutches near Ithaca, New York. To determine experimentally if host parents rejected their own eggs capped by the parasite's shell, cowbird shell fragments were introduced into nonparasitized phoebe clutches either as slipped over intact phoebe eggs (caps) or simply placed into the nests (noncaps). The latency for cowbird egg-fragments to disappear was greater for caps (1–13 days) because all noncaps were removed in <1 day. Whether phoebe eggs hatched was also related to the outcome of the capping treatments: eggs that remained capped for >1 day had a greater probability of hatching failure (0.6) than noncapped eggs (0). Those data suggest that egg-capping by shell-fragments of earlier hatched cowbird eggs reduces phoebes' reproductive success and may represent a fitness cost to hosts in other parasitized species as well.

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