How mountains, rivers and hybridization drove the evolution of the Blue-crowned Manakin

Genetic study identifies four main lineages within this small songbird species.

Evolution never stops. Populations keep changing over time. Occasionally, a geographic barrier arises or a new behavior originates, resulting in some degree of reproductive isolation between the changing populations. Wait long enough and you might end up with different species. And then, the cycle repeats, culminating in the beautiful biodiversity we see today. A recent study in the journal Zoologica Scripta used genetic data to reconstruct the evolutionary history of the Blue-crowned Manakin (Lepidothrix coronata).

Lepidothrix coronata

How many species of Blue-crowned Manakin are there? © Ltoniolo | Wikimedia Commons

 

Four Lineages

Camila Alves Reis and her colleagues analyzed several nuclear and mitochondrial genes to unravel the evolutionary relationships between Blue-crowned Manakins from different locations across South America. These analyses revealed four main lineages. How these lineages arose is an exciting story of rising moutains, expanding rivers and hybridization. Time for an evolutionary bedtime story.

Our story begins about 1.8 million years ago when the northern part of the Andes is forming. The slow build-up of this mountain chain splits the range of the ancestral Blue-crowned Manakin in two. A nothern population (dubbed TA, for Trans-Andean) is separated from a southern population, both going their own evolutionary ways. The TA lineage currently includes two subspecies (velutina and minuscula) based on mitochondrial DNA from another study.

manakin_map

The four main lineages (names TA, A, B and C) and the sampling locations. From: Reis et al. (2019) Zoologica Scripta

 

Rivers and Hybrids

Let’s follow the fate of the southern population, which consequently splits into three distinct lineages. Timing when these lineages formed and estimating their ancestral ranges indicates an important role for different Amazonian rivers. The authors nicely summarize the situation (also see the figure below): “(a) lineage A is delimited to the south by the left margin of the Japurá River, which corresponds to the Imeri and Jaú centres of endemism; (b) lineage B is found between the right (southern) margin of the Japurá River and the northern margin of the Solimões (Amazon), within the Napo centre of endemism; and (c) lineage C is located in the Inambari centre of endemism, to the south of the Amazon‐Solimões.”

There is, however, something peculiar about lineages B and C. The analyses in this study (based on nuclear and mtDNA) suggest that lineage C is the oldest group, whereas lineages A and B cluster together. Other studies (using only mtDNA) reported that lineages B and C are closely related. The disagreement between the nuclear and mitochondrial genes is most likely due to an ancient hybridization event. Birds from lineages B and C hybridized, resulting in the transfer of mtDNA between these lineages. This phenomenon – mitochondrial capture – has been described in numerous other bird species, including another group of manakins (see this blog post)

zsc12395-fig-0005-m

Reconstruction of ancestral ranges highlights the importance of Amazonian rivers. From: Reis et al. (2019) Zoologica Scripta

 

Plumage Patterns

Finally, the researchers uncovered some more fine-grained population structure within the different lineages. In contrast to the main lineages, which were delinated by the Andes or major rivers, these sublineages were not separated by obvious physical barriers. Interestingly, the two subgroups in lineage C (C1 and C2) show differences in plumage patterns: “Subclade C1 was represented primarily by males with completely green plumage or intermediate plumage, that is, typically green underparts and black upper body, whereas subclade C2 included males with completely green or black plumage (not co‐occurring), and some males with intermediate plumage.” These birds might be in the process of further diversification based on plulage patterns. Or they might form a secondary contact zone where two formerly distinct lineages are merging. More research in this area is needed to figure this out. The story continues…

blue-crowned_manakin-2

A Blue-crowned Manakin with green plumage. © Michell Leon | Peruaves

 

References

Cheviron, Z.Hackett, S. J., & Capparella, A. P. (2005). Complex evolutionary history of a Neotropical lowland forest bird (Lepidothrix coronata) and its implications for historical hypotheses of the origin of Neotropical avian diversityMolecular Phylogenetics and Evolution36(2), 338357.

Reis, C. A., Dias, C., Araripe, J., Aleixo, A., Anciães, M., Sampaio, I., Schneider, A. & do Rêgo, P. S. (2020). Multilocus data of a manakin species reveal cryptic diversification moulded by vicariance. Zoologica Scripta49(2), 129-144.

 

This paper has been added to the Pipridae page.

 

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