Jan Stefka& Vince Smith

A hitchhikers guide to the Galápagos

Co-phylogeography of Galápagos mockingbirds and their parasites

BALTRASouth Seymour

BARTOLOMÉBartholomew

ESPAÑOLAHood

FERNANDINANarborough

FLOREANACharles

GENOVESATower

ISABELAAlbemarle

MARCHENABindloe

NORTH SEYMOUR

PINZÓNDuncan

PINTAAbingdon

RÁBIDAJervis

SAN CRISTÓBALChatham

SANTA CRUZIndefatigable

SANTA FÉBarrington

SANTIAGOSan Salvador

0 100(km)

0 60(m)

The Galapágos archipelago

5-9 MYA

c. 2-3 MYA

7.000 YA

Further SEup to 80 MYA?

c. 1-2 MYA

0 100(km)

0 60(m)

The progression rule

YoungestIslands

OldestIslands

Patterns of colonization & diversification linked to geological history

Shallowestnode coalescences

Deepestnode coalescences

BALTRASouth Seymour

BARTOLOMÉBartholomew

ESPAÑOLAHood

FERNANDINANarborough

FLOREANACharles

GENOVESATower

ISABELAAlbemarle

MARCHENABindloe

NORTH SEYMOUR

PINZÓNDuncan

PINTAAbingdon

RÁBIDAJervis

SAN CRISTÓBALChatham

SANTA CRUZIndefatigable

SANTA FÉBarrington

SANTIAGOSan Salvador

0 100(km)

0 60(m)

Galapágos endemics

Galapágos mockingbirds

Mimus spp.

Host systematics

Host mockingbirdsMimus sp.

traditional taxonomy

M. trifasciatusFloreana M. macdonaldi

Hood

M. parvulus

M. melanotisSan Cristobal

East

S.East

Middle+North

West

mtDNA (Arbogast et al, 2006), colonization 1.6-5.5 MYA

mtDNA phylogeny

Galapágos mockingbirds

2004-2008

14 Islands

• Mist nets & potter traps• Wing vein puncture• Ectoparasites collected by dust ruffling

Mockingbird ectoparasites

Amblyceran louseMyrsidea nesomimi11 islands

Ischnoceran louseBrueelia galapagensis6 (smaller) islands

Analgid miteAnalges sp.11 islands

Myrsidea

Brueelia

Analges

Questions

Analges Myrsidea MockingbirdsBrueelia

• Are the host & ectoparasite evolutionary histories congruent?

• Where there is discordance, can we explain it

Biogeography

• To what extent do these diversifications match the successional origins of the islands (progression rule)

• What are the evolutionary histories of these lineages

Data• Homologous 1050 bp fragment COI sequenced in the

mockingbirds and all 3 parasite taxa + outgroups • Complementary nuclear EF1α sequenced in Brueelia &

Analges (not informative in Myrsidea)• 400 Mimus individuals covering the 11 sampled islands

genotyped using microsatellites

Analyses• NJ, ML and BI phylogenetic analyses • Haplotype network built using TCS• Mockingbird microsats analysed via Bayesian clustering

algorithm in Structure• *BEAST to compare mutation rates, infer a multi-species tree

from gene trees, & estimate dates of speciation• GeoPhylo and Google Earth to visualize genetree congruence

Mockingbirds

COI

• 107 sequences (25 haplotypes)

• Island populations often single haplotypes (Floreana)

• Largely congruent with traditional taxonomy

• Basal split separates SE pop. from rest

• No regular migration between islands (Structure analysis)

• Incongruence with ectos must have another explanation (eg ancestral polymorphism)

ML tree

SE

Feather mites (Analges)

COI

• 86 sequences (71 haplotypes), most diverse ecto.

• Haplotypes exclusive to each island (*GbE)

• Broadly maps to host phylogeny, SE clade @ root

• Fastest mutation rate (9x Mimus)

SE

Amblyceran lice (Myrsidea)

COI

• 98 sequences (37 haplotypes)

• Broadly maps to host phylogeny, basal SE clade

• Island groups monophyletic & well supported

• But less pop. structure than mites

• Several haplotypes shared across islands

• Champion & Santa Fe relationship (recent migration perhaps by unknown louse vector)

• Mutation rate approx 2x Mimus

Ischnoceran lice (Brueelia)

SENW

• Dispersal via hitchhiking on hippoboscids?• B. galapagensis ‘contaminant’ on Small Ground Finch • Inter-island migration of Small Ground Finch with

hippoboscids carrying lice? Geospiza fuliginosa

• 45 sequences (8 haplotypes)• Very low levels of genetic diversity• Island populations comprise 1-3 haplotypes• Some genetic isolation between islands

Cophylogeny

• Wide confidence intervals on node ages• Indicative of the sequence of speciation • SE split 1.53 Mya on multi-species tree • Multi-species tree agrees with traditional Mockingbird taxonomy &

geological history• Incongruence best seen in Google Earth visualization

*BEAST (node age & multi-species tree)Single calibration - Espanola (mean 2.9 Mya, SD 0.9)

Geophylogeny

• GeoPhylo• ML gene trees • Lat. long. data• KML file• Google Earth

http://tinyurl.com/3pxboyuGoogle Earth

Summary• Evolutionary histories of Mimus & 2 ectoparasites

(Analges & Myrsidea) broadly congruent• These diversifications can be explained by the

successional origins of the islands (progression rule) and co-diversification of ectoparasite lineages

• Low genetic variability & lack of co-phylogeographic congruence in one ectoparasite lineage (Brueelia)

• May be explained by life history traits of Brueelia linked to phoretic dispersal

Read more shortly at:Stefka et al 2011. A hitchhikers guide to the Galapagos: co-phylogeography of Galapagos mockingbirds and their parasites. BMC Evolutionary Biology (accepted pending revision)

Acknowledgements

...and Douglas Adams

Paquita Hoeck and Lukas Keller (Zoological Museum, University of Zurich, Switzerland) who provided host and parasite samples and some microsat. data.

European Union FP7 Marie Curie Fellowship program.