Sexual size dimorphism in northern giant petrels: ecological correlates and scaling
Northern giant petrels (Macronectes halli) are among the largest and most sexually size dimorphic species of seabirds, with females being only 80% the mass of males. Both sexes scavenge on seal and penguin carrion in the sub-Antarctic ecosystem, but during the breeding season females also feed exten...
Published in: | Oikos |
---|---|
Main Author: | |
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
Blackwell
2004
|
Subjects: | |
Online Access: | http://nora.nerc.ac.uk/id/eprint/12170/ http://onlinelibrary.wiley.com/doi/10.1111/j.0030-1299.2004.12997.x/full |
id |
ftnerc:oai:nora.nerc.ac.uk:12170 |
---|---|
record_format |
openpolar |
spelling |
ftnerc:oai:nora.nerc.ac.uk:12170 2023-05-15T13:45:10+02:00 Sexual size dimorphism in northern giant petrels: ecological correlates and scaling González-Solís, Jacob 2004 http://nora.nerc.ac.uk/id/eprint/12170/ http://onlinelibrary.wiley.com/doi/10.1111/j.0030-1299.2004.12997.x/full unknown Blackwell González-Solís, Jacob. 2004 Sexual size dimorphism in northern giant petrels: ecological correlates and scaling. Oikos, 105 (2). 247-254. https://doi.org/10.1111/j.0030-1299.2004.12997.x <https://doi.org/10.1111/j.0030-1299.2004.12997.x> Biology and Microbiology Ecology and Environment Publication - Article PeerReviewed 2004 ftnerc https://doi.org/10.1111/j.0030-1299.2004.12997.x 2023-02-04T19:27:47Z Northern giant petrels (Macronectes halli) are among the largest and most sexually size dimorphic species of seabirds, with females being only 80% the mass of males. Both sexes scavenge on seal and penguin carrion in the sub-Antarctic ecosystem, but during the breeding season females also feed extensively on other marine food resources and show more pelagic habits than males. The outstanding sexual segregation in foraging and feeding ecology in northern giant petrels suggests that mechanisms maintaining sexual size dimorphism by ecological factors may be operating. I evaluated this possibility by examining ecological correlates with body size and by static allometry analyses. Fledging sex ratio in four consecutive years did not depart from parity. There was no assortative mating by size neither association between the male size with the breeding performance. By contrast, smaller females raised their chick in better condition. Moreover, bill size showed a size dimorphism beyond that expected by body size dimorphism, i.e. when controlling for body mass, males showed relatively longer bill than females. This trait did not deviate from isometry with respect to body size and its phenotypic variability was low, suggesting that the disproportionately large bill of males is related to their more scavenging life style compared to females. In general, the increase and maintenance of sexual size dimorphism in giant petrels is more consistent with an ecological causation rather than a result of sexual selection. Article in Journal/Newspaper Antarc* Antarctic Giant Petrels Natural Environment Research Council: NERC Open Research Archive Antarctic Oikos 105 2 247 254 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
topic |
Biology and Microbiology Ecology and Environment |
spellingShingle |
Biology and Microbiology Ecology and Environment González-Solís, Jacob Sexual size dimorphism in northern giant petrels: ecological correlates and scaling |
topic_facet |
Biology and Microbiology Ecology and Environment |
description |
Northern giant petrels (Macronectes halli) are among the largest and most sexually size dimorphic species of seabirds, with females being only 80% the mass of males. Both sexes scavenge on seal and penguin carrion in the sub-Antarctic ecosystem, but during the breeding season females also feed extensively on other marine food resources and show more pelagic habits than males. The outstanding sexual segregation in foraging and feeding ecology in northern giant petrels suggests that mechanisms maintaining sexual size dimorphism by ecological factors may be operating. I evaluated this possibility by examining ecological correlates with body size and by static allometry analyses. Fledging sex ratio in four consecutive years did not depart from parity. There was no assortative mating by size neither association between the male size with the breeding performance. By contrast, smaller females raised their chick in better condition. Moreover, bill size showed a size dimorphism beyond that expected by body size dimorphism, i.e. when controlling for body mass, males showed relatively longer bill than females. This trait did not deviate from isometry with respect to body size and its phenotypic variability was low, suggesting that the disproportionately large bill of males is related to their more scavenging life style compared to females. In general, the increase and maintenance of sexual size dimorphism in giant petrels is more consistent with an ecological causation rather than a result of sexual selection. |
format |
Article in Journal/Newspaper |
author |
González-Solís, Jacob |
author_facet |
González-Solís, Jacob |
author_sort |
González-Solís, Jacob |
title |
Sexual size dimorphism in northern giant petrels: ecological correlates and scaling |
title_short |
Sexual size dimorphism in northern giant petrels: ecological correlates and scaling |
title_full |
Sexual size dimorphism in northern giant petrels: ecological correlates and scaling |
title_fullStr |
Sexual size dimorphism in northern giant petrels: ecological correlates and scaling |
title_full_unstemmed |
Sexual size dimorphism in northern giant petrels: ecological correlates and scaling |
title_sort |
sexual size dimorphism in northern giant petrels: ecological correlates and scaling |
publisher |
Blackwell |
publishDate |
2004 |
url |
http://nora.nerc.ac.uk/id/eprint/12170/ http://onlinelibrary.wiley.com/doi/10.1111/j.0030-1299.2004.12997.x/full |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic Giant Petrels |
genre_facet |
Antarc* Antarctic Giant Petrels |
op_relation |
González-Solís, Jacob. 2004 Sexual size dimorphism in northern giant petrels: ecological correlates and scaling. Oikos, 105 (2). 247-254. https://doi.org/10.1111/j.0030-1299.2004.12997.x <https://doi.org/10.1111/j.0030-1299.2004.12997.x> |
op_doi |
https://doi.org/10.1111/j.0030-1299.2004.12997.x |
container_title |
Oikos |
container_volume |
105 |
container_issue |
2 |
container_start_page |
247 |
op_container_end_page |
254 |
_version_ |
1766214941645209600 |