Nestling Sex Ratios in the Yellow-naped Amazon: No Evidence for Adaptive Modification
نویسندگان
چکیده
Many birds, including some parrots, may adjust the sex ratio of their offspring in relation to the relative fitness benefits of sons and daughters. We investigated nestling sex ratios in Yellow-naped Amazons (Amazona auropalliata) using a molecular sexing technique that amplifies intronic regions of the CHDW and CHD-Z genes in birds. We examined all nestlings in 37 complete clutches comprising 77 chicks. The overall nestling sex ratio did not differ from unity. Sex allocation was not associated with hatch date, sequence of hatching, or clutch size. We also found no difference in sex ratio between two regional dialects. Female Yellow-naped Amazons may be unable to control their hatchling sex ratio. Alternatively, there may be no fitness benefits to females producing more of one sex in relation to the factors we measured here.
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