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Molecular determination of sex-ratio in Yellowhammer Emberiza citrinella offspring

journal contribution
posted on 1999-01-01, 00:00 authored by A Pagliani, Patricia LeePatricia Lee, R Bradbury
Theory predicts skewed offspring sex-ratios in a range of situations in which the economics of producing the two sexes differ. Offspring sex-ratio skews in birds are relatively scarcely observed compared to other taxa. This could be because avian molecular sexing techniques, which allow young birds to be sexed, have only recently become available. Alternatively, birds may be largely constrained from adaptively manipulating the sex-ratio of their offspring. We used a recently-developed molecular sexing technique for birds to sex 420 Yellowhammer Emberiza citrinella offspring from 168 clutches found in Oxfordshire. Clutch sex-ratio of the population did not depart from the expected binomial distribution, and there was no variation in clutch sex-ratio with laying date, breeding attempt, or a variety of habitat variables which were predicted to differentially affect the survival and future reproductive success of offspring of the two sexes. There was no difference in size or growth rate of the sexes and nestling mortality was not sex-biased. Hence, although we can identify possible advantages of manipulating the sex-ratio in this species, it seems not to be used as a breeding strategy. Given the lack of consistent evidence for skewed avian offspring sex-ratios, more experimental work is required to determine whether, and how, birds may adaptively manipulate their offspring sex-ratio.

History

Journal

Journal of avian biology

Volume

30

Issue

3

Pagination

239 - 244

Publisher

Wiley

Location

London, England

ISSN

0908-8857

eISSN

1600-048X

Language

eng

Notes

September

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

1999, Wiley