Low hatching success in the critically endangered kākāpō (Strigops habroptilus) is driven by early embryo mortality not infertility

Abstract

In many endangered species, reproductive failure is a major barrier to recovery. The critically endangered kākāpō (Strigops habroptilus) exemplifies this challenge: 61% of their eggs fail to hatch, and of these 73% show no sign of development. Undeveloped eggs have previously been attributed to male infertility, but recent studies of non-threatened bird species suggest fertilisation failure is rare in the wild. The underlying causes of fertilisation failure and embryo death differ, so distinguishing between them is essential for effective conservation management. Here we show that the majority (72%, n=124) of undeveloped kākāpō eggs are fertilised, and combine this with conservation programme data on natural copulations, artificial inseminations, and paternity of developed eggs, to generate the most precise estimate to date of fertility in a wild population. We also demonstrate, for the first time in a wild bird, that artificial insemination results in greater numbers of sperm reaching the egg.

Expanding the conservation genomics toolbox: Incorporating structural variants to enhance genomic studies for species of conservation concern

“…Similarly, a large inversion resulting in a supergene underlies significant morphological and behavioural differences among white‐striped and tan‐striped morphs in White‐throated sparrows, with aggressiveness being monogenic in the white‐striped morph (Merritt et al, 2020 ). Although many fitness traits are likely to be polygenic, including traits of conservation interest such as disease susceptibility, reduced fertility and developmental abnormalities (e.g., Moran et al, 2021 ; Murchison et al, 2012 ; Roelke et al, 1993 ; Savage et al, 2020 preprint), those impacted by supergenes are likely to have relatively simple inheritance patterns which will enable their characterization and management.…”

Expanding the conservation genomics toolbox: incorporating structural variants to enhance genomic studies for species of conservation concern

“…For intensively managed threatened species, complex traits of conservation interest include, but are not limited to, disease susceptibility, reduced fertility and developmental abnormalities (e.g., Moran et al, 2021;Murchison et al, 2012;Roelke, Martenson, & O'Brien, 1993;Savage, Crane, Team, & Hemmings, 2020).…”

Expanding the conservation genomics toolbox: incorporating structural variants to enhance genomic studies for species of conservation concern

“…Similarly, a large inversion resulting in a supergene underlies significant morphological and behavioral differences among white-striped and tan-striped morphs in White-throated sparrows, with aggressiveness being monogenic in the white-striped morph (Merritt et al, 2020). Although many fitness traits are likely to be polygenic, including traits of conservation interest such as disease susceptibility, reduced fertility and developmental abnormalities (e.g., Moran et al, 2021;Murchison et al, 2012;Roelke, Martenson, & O'Brien, 1993;Savage, Crane, Team, & Hemmings, 2020), those impacted by supergenes are likely to have relatively simple inheritance patterns which will enable their characterization and management.…”