Intra-clutch ratio of yolk progesterone level changes with laying date in rockhopper penguins: a strategy to influence brood reduction?
Hatching asynchrony in avian species generally leads to a size hierarchy among siblings, favouring the first-hatched chicks. Maternally deposited hormones affect the embryo and chick's physiology and behaviour. It has been observed that progesterone, a hormone present at higher levels than othe...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2011-01-01
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| Series: | PLoS ONE |
| Online Access: | https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/22110758/?tool=EBI |
| _version_ | 1818436165060001792 |
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| author | Maud Poisbleau Laurent Demongin Charline Parenteau Marcel Eens |
| author_facet | Maud Poisbleau Laurent Demongin Charline Parenteau Marcel Eens |
| author_sort | Maud Poisbleau |
| collection | DOAJ |
| description | Hatching asynchrony in avian species generally leads to a size hierarchy among siblings, favouring the first-hatched chicks. Maternally deposited hormones affect the embryo and chick's physiology and behaviour. It has been observed that progesterone, a hormone present at higher levels than other steroid hormones in egg yolks, is negatively related to body mass in embryos, chicks and adults. A differential within-clutch progesterone deposition could therefore be linked to the size hierarchy between siblings and to the resulting brood reduction. We tested whether yolk progesterone levels differed between eggs according to future parental ability to feed the entire clutch in wild rockhopper penguins Eudyptes chrysocome. This species presents a unique reversed egg-size dimorphism and hatching asynchrony, with the larger second-laid egg (B-egg) hatching before the smaller first-laid egg (A-egg). Yolk progesterone levels increased only slightly with female body mass at laying. However, intra-clutch ratios were not related to female body mass. On the other hand, yolk progesterone levels increased significantly with the date of laying onset for A-eggs while they decreased for B-eggs. Early clutches therefore had proportionally more progesterone in the B-egg compared to the A-egg while late clutches had proportionally less progesterone in the B-egg. We propose that females could strategically regulate yolk progesterone deposition within clutches according to the expected food availability during chick growth, an adaptive strategy to adjust brood reduction to conditions. We also discuss these results, relating to yolk progesterone, in the broader context of other yolk steroids. |
| first_indexed | 2024-12-14T17:04:26Z |
| format | Article |
| id | doaj.art-ec7e521f33414531aeeb3f70f377a673 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-14T17:04:26Z |
| publishDate | 2011-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-ec7e521f33414531aeeb3f70f377a6732022-12-21T22:53:46ZengPublic Library of Science (PLoS)PLoS ONE1932-62032011-01-01611e2776510.1371/journal.pone.0027765Intra-clutch ratio of yolk progesterone level changes with laying date in rockhopper penguins: a strategy to influence brood reduction?Maud PoisbleauLaurent DemonginCharline ParenteauMarcel EensHatching asynchrony in avian species generally leads to a size hierarchy among siblings, favouring the first-hatched chicks. Maternally deposited hormones affect the embryo and chick's physiology and behaviour. It has been observed that progesterone, a hormone present at higher levels than other steroid hormones in egg yolks, is negatively related to body mass in embryos, chicks and adults. A differential within-clutch progesterone deposition could therefore be linked to the size hierarchy between siblings and to the resulting brood reduction. We tested whether yolk progesterone levels differed between eggs according to future parental ability to feed the entire clutch in wild rockhopper penguins Eudyptes chrysocome. This species presents a unique reversed egg-size dimorphism and hatching asynchrony, with the larger second-laid egg (B-egg) hatching before the smaller first-laid egg (A-egg). Yolk progesterone levels increased only slightly with female body mass at laying. However, intra-clutch ratios were not related to female body mass. On the other hand, yolk progesterone levels increased significantly with the date of laying onset for A-eggs while they decreased for B-eggs. Early clutches therefore had proportionally more progesterone in the B-egg compared to the A-egg while late clutches had proportionally less progesterone in the B-egg. We propose that females could strategically regulate yolk progesterone deposition within clutches according to the expected food availability during chick growth, an adaptive strategy to adjust brood reduction to conditions. We also discuss these results, relating to yolk progesterone, in the broader context of other yolk steroids.https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/22110758/?tool=EBI |
| spellingShingle | Maud Poisbleau Laurent Demongin Charline Parenteau Marcel Eens Intra-clutch ratio of yolk progesterone level changes with laying date in rockhopper penguins: a strategy to influence brood reduction? PLoS ONE |
| title | Intra-clutch ratio of yolk progesterone level changes with laying date in rockhopper penguins: a strategy to influence brood reduction? |
| title_full | Intra-clutch ratio of yolk progesterone level changes with laying date in rockhopper penguins: a strategy to influence brood reduction? |
| title_fullStr | Intra-clutch ratio of yolk progesterone level changes with laying date in rockhopper penguins: a strategy to influence brood reduction? |
| title_full_unstemmed | Intra-clutch ratio of yolk progesterone level changes with laying date in rockhopper penguins: a strategy to influence brood reduction? |
| title_short | Intra-clutch ratio of yolk progesterone level changes with laying date in rockhopper penguins: a strategy to influence brood reduction? |
| title_sort | intra clutch ratio of yolk progesterone level changes with laying date in rockhopper penguins a strategy to influence brood reduction |
| url | https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/22110758/?tool=EBI |
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