Demographic drivers of reproductive failure in a threatened bird: Insights from a decade of data

• 成果类型: Article
• 署名作者: Morland, Fay; Ewen, John G.; Santure, Anna W.; Brekke, Patricia; Hemmings, Nicola
• 署名单位: University of Sheffield; Zoological Society of London; University of Otago; University of Auckland
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-10889
• DOI: 10.1073/pnas.2319104121
• 发表日期: 2024-09-03
• 关键词: hatching failure; sex-ratio; unhatched eggs; genetic similarity; inbreeding depression; extrapair paternity; island populations; sperm competition; embryo mortality; house sparrow

摘要

Hatching failure affects up to 77% of eggs laid by threatened bird species, yet the true prevalence and drivers of egg fertilization failure versus embryo mortality as underlying mechanisms of hatching failure are unknown. Here, using ten years of data comprising 4,371 eggs laid by a population of a threatened bird, the hihi (Notiomystis cincta), we investigate the relative importance of infertility and embryo death as drivers of hatching failure and explore population- level factors associated with them. We show that of the 1,438 eggs that failed to hatch (33% of laid eggs) between 2010 and 2020, 83% failed due to embryo mortality, with the majority failing in the early stages of embryonic development. In the most comprehensive estimates of infertility rates in a wild bird population to date, we find that fertilization failure accounts for around 17% of hatching failure overall and is more prevalent in years where the population is smaller and more male biased. Male embryos are more likely to die during early development than females, but we find no overall effect of sex on the successful development of embryos. extra- pair offspring; however, we find no effect of inbreeding nor extra- pair paternity on embryo mortality. Accurately distinguishing between infertility and embryo mortality in this study provides unique insight into the underlying causes of reproductive failure over a long- term scale and reveals the complex risks of small population sizes to the reproduction of threatened species.