Population structure and inter-species admixture within a likely extinct yet formerly widespread Hawaiian honeycreeper.

The Hawaiian honeycreepers simultaneously represent one of the mostspectacular avian adaptive radiations and are one of the most endangeredavian groups. This clade’s few geographically widespread species canserve as a model to understand population-level processes shapingdifferentiation and characterizing decline. One such species is the likelyextinct ʻōʻū (Psittirostra psittacea), a parrot-like beaked honeycreeperwith a frugivorous feeding ecology. We compiled morphological andhybridization-captured ancient DNA datasets for the ʻōʻū from museumspecimens from across the Hawaiian archipelago. We find (i) genomicdifferentiation among ʻōʻū from Kauaʻi, Lānaʻi, and the remainingHawaiian Islands and (ii) a larger phenotype on Kauaʻi and smaller MauiNui morphological phenotypes. While the differentiated population onKauaʻi is likely a result of Kauaʻi’s geographical isolation, the divergentpopulation on Lānaʻi is harder to explain by biogeography alone. Thus, weinvestigated whether the unexpected divergence of Lānaʻi ʻōʻū could beattributed to inter-species admixture with the geographically overlapping,now extinct ‘parrot-billed’ Lānaʻi hookbill (Dysmorodrepanis munroi) or acritically endangered Maui endemic, the kiwikiu (Pseudonestor xanthophrys).We detect significant admixture between the Lānaʻi ʻōʻū population andthe Lānaʻi hookbill, possibly explaining the observed population structureand associating interspecific breeding with populations on the precipice ofextinctio

Project(s)

Priority 4: Accelerated Taxonomy

Funder

Funder name	Awards
Research England, United Kingdom	Expanding Excellence in England (E3) Fund
Smithsonian Institution, United States	Buck Fellowship
National Science Foundation, United States	DEB-1717498
Beeson Fund, United States