A unique opportunity to study fertility and maternal investment in the critically endangered kakapo (Strigops habroptilus)

研究极度濒危鸮鹦鹉（Strigops habroptilus）的生育力和母性投资的独特机会

基本信息

批准号：
NE/T00200X/1
负责人：
Nicola Hemmings
金额：
$ 6.37万
依托单位：
University of Sheffield
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2019
资助国家：
英国
起止时间：
2019 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FT00200X%2F1
关键词：
unique opportunity study fertility maternal

项目摘要

The kakapo (Strigops habroptilus) is a critically endangered flightless parrot native to New Zealand. Only 147 currently exist in the world, all managed on predator-free offshore islands by the New Zealand Department of Conservation's Kakapo Recovery Team. Managing the recovery of the population is challenging: kakapo only breed when conditions are good, and when they do, approximately 70% of their eggs fail to hatch. Of these unhatched eggs around 75% appear to be 'infertile' - that is, they show no sign of development. However, undeveloped eggs can result either from (i) fertilisation failure, potentially caused by insufficient or poor quality sperm, or (ii) early embryo death, which may be linked to poor female condition, inbreeding, or the environment. It is difficult to distinguish unfertilised eggs from those that have suffered early embryo death, but we have previously established methods for doing this, allowing us to identify and mitigate the underlying causes of hatching failure.Kakapo breeding is highly unpredictable, being dependent on abundant food from several tree species with irregular fruiting cycles. Kakapo breeding seasons occur on average every 2-4 years and fewer than 50% of females typically lay eggs. There have been only three major breeding seasons - where the majority of females attempted to breed - in the last 20 years. This year (2019), exceptional ecological conditions have induced record-breaking reproductive rates, with over 90% of females laying eggs before the breeding season was even predicted to start. The Kakapo Recovery Team recently reported the first 5-egg clutch on record, and an unprecedented second round of nesting is expected later in the season. Until now, the kakapo's small population size and slow reproductive rate has limited our understanding of its reproductive biology, but this season's extremely unusual circumstances provide a once-in-a-generation opportunity to obtain the sample sizes required to address crucial questions about the causes of reproductive failure in this critically endangered bird.Our proposed research will analyse all unhatched kakapo eggs produced this season, using our own established methods for determining whether hatching failure is due to fertilisation failure or early embryo mortality. We will quantify the number of sperm that reach ova to assess whether fertilisation failure is caused by a lack of sperm, and identify the developmental stage at which embryos die, with the aim of linking this to external causes. Finally, we will quantify how kakapo females differ in reproductive behaviour and investment by recording the number, size, and timing of eggs laid, and collecting data on how females care for their offspring. We will then assess how these traits are related to fertility, embryo survival, chick development, and other factors such as age, condition, and reproductive history, for which data are available from long-term monitoring by the Kakapo Recovery Team. This work will be crucial for planning the future management of this iconic species, and will substantially improve our broader understanding of reproductive problems in birds.

Kakapo（Strigops Habroptilus）是新西兰本地的极度濒临灭绝的无飞鹦鹉。目前只有147个存在于世界上，全部由新西兰保护局的卡卡波恢复团队管理。管理人口的恢复是具有挑战性的：卡卡波只有在情况良好的情况下繁殖，而当他们这样做时，大约70％的卵无法孵化。在这些未触及的卵中，约75％的卵似乎是“不育”的 - 也就是说，它们没有发育的迹象。但是，未发育的卵可能是由于（i）受精衰竭而导致的，可能是由于精子不足或质量不足引起的，或者（ii）早期胚胎死亡可能与女性状况不佳，近交或环境有关。很难将未剥皮的鸡蛋与遭受早期胚胎死亡的卵区分开，但是我们以前已经建立了这样做的方法，从而使我们能够识别并减轻孵化失败的根本原因。Kakapo育种非常不可预测，这是无法预测的，它依赖于具有符合规范的Fruiting Cycles的几种树种的丰富食物。卡卡波繁殖季节平均每2-4年发生一次，而女性中不到50％的繁殖季节通常产卵。在过去的20年中，只有三个主要的繁殖季节 - 大多数女性试图繁殖。今年（2019年），特殊的生态状况引起了创纪录的生殖率，甚至预计繁殖季节之前，有超过90％的女性在繁殖季节之前产卵。 Kakapo Recovery Team最近报道了有记录的第一个5-EGG离合器，预计本赛季晚些时候将有前所未有的第二轮筑巢。 Until now, the kakapo's small population size and slow reproductive rate has limited our understanding of its reproductive biology, but this season's extremely unusual circumstances provide a once-in-a-generation opportunity to obtain the sample sizes required to address crucial questions about the causes of reproductive failure in this critically endangered bird.Our proposed research will analyse all unhatched kakapo eggs produced this season, using our own established methods for determining whether孵化失败是由于受精衰竭或早期胚胎死亡率引起的。我们将量化到达OVA的精子数量，以评估受精失败是否是由于缺乏精子引起的，并确定胚胎死亡的发育阶段，目的是将其与外部原因联系起来。最后，我们将通过记录产卵的数量，大小和时间来量化Kakapo女性在生殖行为和投资方面的差异，并收集有关女性如何照顾其后代的数据。然后，我们将评估这些特征如何与生育能力，胚胎生存，鸡发育以及其他因素（例如年龄，状况和生殖历史）相关，这些因素可从Kakapo恢复团队的长期监测中获得数据。这项工作对于计划这种标志性物种的未来管理至关重要，并将大大提高我们对鸟类生殖问题的广泛理解。