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Successful same-sex pairing in Laysan albatross
Lindsay C Young1, Brenda J Zaun, Eric A Vanderwerf
1Ecology, Evolution and Conservation Biology Program, Department of Zoology, University of Hawaii, Honolulu, HI 96822, USA. lindsayc@hawaii.edu
Biology Letters
|May 29, 2008
Summary
Unrelated female Laysan albatross form long-term pairs and cooperatively breed due to a skewed sex ratio. This social structure shift demonstrates cooperation in a monogamous species, offering a better breeding alternative.
Area of Science:
- Animal Behavior
- Evolutionary Biology
- Conservation Science
Background:
- Cooperative breeding is rare in unrelated same-sex pairs.
- It's often explained by kin selection or altruism.
- Laysan albatross exhibit unique social structures.
Purpose of the Study:
- Document long-term pairing of unrelated female Laysan albatross.
- Investigate the role of skewed sex ratios in cooperative breeding.
- Understand the evolution of social behavior in monogamous species.
Main Methods:
- Observed Laysan albatross pairs on Oahu over several years.
- Determined pair composition (male-female, female-female).
- Assessed breeding success and genetic relatedness of offspring.
Main Results:
- 31% of pairs were female-female, with a 59% female sex ratio due to immigration.
- Female-female pairs had lower, but still beneficial, fledging success compared to male-female pairs.
- In successful long-term female-female pairs, offspring were genetically related to both females.
Conclusions:
- Skewed sex ratios can drive social structure changes and cooperative breeding in monogamous species.
- Cooperative breeding in female-female Laysan albatross pairs provides a viable reproductive strategy.
- Accurate genetic sexing is crucial for studying monomorphic species.
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