Using bioacoustic data to test species limits in an Indo-Pacific island radiation of Macropygia cuckoo doves

Abstract

The characterization of species limits and diversification patterns across the geographically complex Indo-Pacific region has presented biogeographers and evolutionary biologists with great challenges. In the present study, we investigated the brown cuckoo dove (Macropygia amboinensis s.l.) species complex, whose distribution spans this entire region. We analyzed whether bioacoustic data are congruent with previous plumage-based classifications and whether glacial land bridges have impacted bioacoustic diversification in these doves. Using an unusually large vocal dataset of > 300 recordings from over 30 islands and 24 taxa, we analyzed 29 bioacoustic frequency and temporal parameters and tested for a correlation between geographical and bioacoustic distances. We found a weak correlation between geographical and bioacoustic distances. We identified numerous lineages that are bioacoustically distinct and proposed their elevation to the species level, leading to a doubling of the number of species in this complex and indicating a high proportion of cryptic species-level diversity that has previously gone unrecognized.