Social selection parapatry in Afrotropical sunbirds

Research output: Contribution to journalJournal articleResearchpeer-review

Jay P. McEntee, Joshua V. Peñalba, Chacha Werema, Elia Mulungu, Maneno Mbilinyi, David Moyer, Louis André Hansen, Jon Fjeldså, Rauri C. K. Bowie

The extent of range overlap of incipient and recent species depends on the type and magnitude of phenotypic divergence that separates them, and the consequences of phenotypic divergence on their interactions. Signal divergence by social selection likely initiates many speciation events, but may yield niche-conserved lineages predisposed to limit each others’ ranges via ecological competition. Here, we examine this neglected aspect of social selection speciation theory in relation to the discovery of a nonecotonal species border between sunbirds. We find that Nectarinia moreaui and Nectarinia fuelleborni meet in a ∼6 km wide contact zone, as estimated by molecular cline analysis. These species exploit similar bioclimatic niches, but sing highly divergent learned songs, consistent with divergence by social selection. Cline analyses suggest that within-species stabilizing social selection on song-learning predispositions maintains species differences in song despite both hybridization and cultural transmission. We conclude that ecological competition between moreaui and fuelleborni contributes to the stabilization of the species border, but that ecological competition acts in conjunction with reproductive interference. The evolutionary maintenance of learned song differences in a hybrid zone recommend this study system for future studies on the mechanisms of learned song divergence and its role in speciation.

Original languageEnglish
JournalEvolution
Volume70
Issue number6
Pages (from-to)1307-1321
Number of pages15
ISSN0014-3820
DOIs
Publication statusPublished - Jun 2016

    Research areas

  • Bird song, cline, hybrid zone, HZAR, sexual selection, species borders

ID: 173804418