GeographyofSpecia/on
Modelsofspecia-onhavetradi-onallybeenorganizedbasedongeography
•  Allopatricspecia/on
-Vicariantspecia/on
-Peripatricspecia/on
•  Parapatricspecia/on
•  Sympatricspecia/on
Thegeographyofspecia/onhasbeenhotlydebated:
Doesspecia/onrequirecompletegeographicisola/on,orcanitoccurinpopula/ons
thatexchangegenestoalimitedextent(parapatric)orfreely(sympatric)?
1
GeographyofSpecia/on
1.  AllopatricSpecia-on–Vicariantspecia-on
Theevolu/onofreproduc/veisola/onduringgeographicisola/on
Haslongbeenrecognizedasaprinciplemechanismofspecia/on,
butchampionedbyErnstMayr(e.g.,Mayr1963).
2
GeographyofSpecia/on
1.  AllopatricSpecia-on–Vicariantspecia-on
Vicariance:establishmentofabarriersepara/ngpopula/onsthatwerealreadypresent
Geographicsepara/onofpopula/onscanoccurthroughclima/cor
geologicalevents(e.g.,eleva/onoflandbridges,glacia/on,forma/onof
mountains,con/nentaldriQ)
3
GeographyofSpecia/on
1.  AllopatricSpecia-on
Biogeographicalobserva/ons:
1) Allopatryofsisterspecies
Bonefishesoccurintropicalsandflatsacrosstheglobe
Onceclassifiedasasinglepantropicalspecies,based
4
onconservedmorphological/ecologicaltraits
GeographyofSpecia/on
1.  AllopatricSpecia-on
Biogeographicalobserva/ons:
1) Allopatryofsisterspecies
PhylogenyofAlbulamtDNAhaplotypes
Sisterspeciesandcladesareallopatric
MostdivisionsaYributedtogeological
andoceanographicboundaries
(e.g.,mid-Atlan/cexpanse,SundaShelf)
(Colbornetal.2001)
5
GeographyofSpecia/on
1.  AllopatricSpecia-on
Biogeographicalobserva/ons:
2) Geographicconcordanceofspeciesrangeboundariesandhybridzones
red-shaQedflicker(west)
yellow-shaQedflicker(east)
Bullock’soriole(west)
Bal/moreoriole(east)
6
GeographyofSpecia/on
1.  AllopatricSpecia-on
Biogeographicalobserva/ons:
3) Theabsenceofsisterspecieswhereisola/onwasunlikely
•  Noevidenceforsisterbirdspecieson51oceanicislandssurveyed
byCoyne&Price(2000)
•  Nosisterlizardspeciesonthethesmallestislands(<3000km2)in
theCaribbean(Losos&Schluter2000)–althoughintra-island
specia/onoccurredonlargeislands
7
GeographyofSpecia/on
Galapagosarchipelago,withnumberof
Darwin’sFinchspeciesbreedingoneachisland,
andaphylogenyofDarwin’sFinchesshowing
rela/ontomainlandancestor.
(Lomolinoetal.2010)
8
GeographyofSpecia/on
Specia/oncycleinDarwin’sFinchescomprisesthreesteps:
1)  Coloniza/onofthearchipelago
2)  Establishmentofallopatric
popula/ons
3)  Establishmentofsympatry
(Grantetal.1996)
9
GeographyofSpecia/on
GeologicalhistoryoftheGalapagosarchipelagooverthelast3Ma,
sincethe/metheywerecolonizedbyancestralDarwin'sFinches
present
2MaBP
1MaBP
3MaBP
(Grantetal.1996)
10
GeographyofSpecia/on
GeologicalhistoryoftheGalapagosarchipelagooverthelast3Ma,
sincethe/metheywerecolonizedbyancestralDarwin'sFinches
present
2MaBP
1MaBP
3MaBP
(Grantetal.1996)
11
GeographyofSpecia/on
GeologicalhistoryoftheGalapagosarchipelagooverthelast3Ma,
sincethe/metheywerecolonizedbyancestralDarwin'sFinches
present
2MaBP
1MaBP
3MaBP
(Grantetal.1996)
12
GeographyofSpecia/on
GeologicalhistoryoftheGalapagosarchipelagooverthelast3Ma,
sincethe/metheywerecolonizedbyancestralDarwin'sFinches
present
2MaBP
1MaBP
3MaBP
(Grantetal.1996)
13
GeographyofSpecia/on
Accumula/onofDarwin'sFinchspeciesinrela/ontotheincreaseinnumber
ofGalapagosislands
islandsinthe
Galapagos
Darwin’sFinch
species
14
GeographyofSpecia/on
HoneycreepersontheHawaiianarchipelago
K
O
M
H
OG=OutGroup
(Lomolinoetal.2010)
15
GeographyofSpecia/on
Bodysize(PC1)
Widthofwingbar(mm)
1.  AllopatricSpecia-on
Biogeographicalobserva/ons:
4) Increasedreproduc/veisola/onwithincreasedgeographicdistance
Siberianpopula/onsofgreenishwarbler
(YKandST)areamongthemostdivergentin
plumage(i.e.,wingbarwidth)andgene/cs,
notshown,butsimilarinbodysize
(Irwinetal.2001)
16
GeographyofSpecia/on
PC2-Increasing
frequencyrange
1.  AllopatricSpecia-on
Biogeographicalobserva/ons:
4) Increasedreproduc/veisola/onwithincreasedgeographicdistance
PC1-Increasinglengthofsong,
numberofunitsandtypes
Siberianpopula/onsofgreenishwarbler
(TLandBK)areamongthemostdivergentin
songs(morecomplex),Himalayan
popula/onshavesimilarsongs(simplest)
(Irwinetal.2001)
17
GeographyofSpecia/on
2.  PeripatricSpecia-on–aspecialkindofallopatricspecia/on,usually
dueto“foundereffect”andhighgene/cdriQ
18
GeographyofSpecia/on
2.  PeripatricSpecia-on
CocosIsland
CocosFinch
(Pinaroloxiasinornata)
Mostcloselyrelatedto
cladeoftreefinchesin
Galapagos
19
GeographyofSpecia/on
3.  ParapatricSpecia-on–variablepopula/onsdivergealongselec/vegradient
20
GeographyofSpecia/on
3.  ParapatricSpecia-on
Howdoweknowthisisallopatricandnotparapatricspecia/on?
red-shaQedflicker(west)
yellow-shaQedflicker(east)
Bullock’soriole(west)
Bal/moreoriole(east)
21
GeographyofSpecia/on
3.  ParapatricSpecia-on
Pleistoceneglacialperiod
ScenarioI
ScenarioII
Whichscenario(IorIIatright)iscompa/blewithallopatric
specia/onof3sisterspeciespairsdrivenbyPleistoceneglacia/ons?
22
GeographyofSpecia/on
4.  SympatricSpecia-on
23
GeographyofSpecia/on
4.  SympatricSpecia-on
Twofundamentalproblemsforsympatricspecia/on:
1.  Divergentselec/oniscounteractedbygeneflow
•  solu/on:evolu/onofassorta/vema/ng,orcloselinkagebetween
reproduc/velyisolatedgenes
2.  Coexistenceinsteadofcompe//veexclusion
•  solu/on:specia/onisdrivenbyecologicaldivergence
24
GeographyofSpecia/on
4. SympatricSpecia-on
Criteriaforconcludingthatspecia/onoccurredinsympatry
(fromCoyne&Orr2004):
1. Speciesmustbelargelyorcompletelysympatric
2. Thespeciesmusthavesubstan/al(gene/cally-based)reproduc/ve
isola/on
3. Thesympatricspeciesmustbesisterspecies
4. Thebiogeographichistoryofthespeciesmustmakeanallopatricphase
veryunlikely
25
GeographyofSpecia/on
4.  SympatricSpecia-on
Casesofsympatricspecia/on?
•  Darwin’sFinches
•  S/cklebackspeciespairs
•  CichlidfishinAfricanlakes
•  AfricanIndigobirds
26
GeographyofSpecia/on
4.  SympatricSpecia-on–cichlidfishesinAfrica.
Here,distribu/onandphylogenycombineto
suggestsympatricspecia/on
CichlidfishinAfricanlakes
Lake
Area(km2)
Endemiccichlid
species
Maximumageof Majorfish
lake
lineage
Victoria
68635
~500
0.75myr
Haplochromine
Malawi
29604
659-1000
2myr
Haplochromine
Tanganyika
32893
170-250
12myr
Several
Nabugabo
29
5
0.004myr
Haplochromine
BarombiMbo
4
11
1myr
Tilapiine
Bermin
0.6
9
2.5myr
Tilapiine
27
GeographyofSpecia/on
4.  SympatricSpecia-on
LakeMalawiwasinvadedbyariverinegeneralist
~700000yearsago
Commonancestorsubsequentlydivergedinto
sand-dwellingandrock-dwellinglineages
(Lomolinoetal.2010)
28
(fromDanley&Kocher2001)
GeographyofSpecia/on
4.  SympatricSpecia-on
Rock-dwellinglineagedivergedinto~12generadis/nguished
primarilyontrophicmorphology,sugges/ngtheimportanceof
trophiccompe//onduringradia/on
Subsequently,~25speciespergenusdiverged
presumablyinresponsetosexualselec/onvia
femalechoiceformalecolourpaYern.
(Lomolinoetal.2010)
29
(fromDanley&Kocher2001)
GeographyofSpecia/on
4.  SympatricSpecia-on
Selec/onfixedopsinproteins
withdifferentlightabsorbance
proper/es
Divergentvisualsystem
coincideswithdivergentmale
breedingcolora/on
waterclarity
(fromTeraietal.2006)
30
21. Telford, M. J., Lockyer, A. E., Cartwright-Finch, C. & Littlewood, D. T. J. Combined large and small
subunit ribosomal RNA phylogenies support a basal position of the acoelomorph flatworms. Proc.
R. Soc. Lond. B 270, 1077–1083 (2003).
cies among seven indigobird species in West Africa (samples from
Cameroon and Nigeria) and four species in southern Africa
(samples from Zimbabwe, Zambia, Malawi and South Africa).
Figure 2 shows unrooted mtDNA haplotype trees for indigobirds.
Species within each region share a set of closely related haplotypes,
with overall diversity similar to that typically found within a single
avian species. For example, a maximum divergence of 2.1% between
GeographyofSpecia/on
Supplementary Information accompanies the paper on www.nature.com/nature.
Acknowledgements We thank M. Akam and R. Jenner for comments on the manuscript, I. Ruiz
Trillo for sharing unpublished results, and the scientists of Kristineberg Marine Station for help in
sample collection. We are grateful for support from the Wellcome Trust to M.J.T. and to D.T.J.L.
4.  SympatricSpecia-on
Indigobirds(Viduasp.)
..............................................................
Host-specificbroodparasites
Competing interests statement The authors declare that they have no competing financial
interests.
Correspondence and requests for materials should be addressed to M.J.T. ([email protected]).
Newly determined sequences have been submitted to GenBank under accession numbers
AY291292–AY291293.
Speciation by host switch in
brood parasitic indigobirds
-  Maleindigobirdsmimichostsongs
Michael D. Sorenson1,2, Kristina M. Sefc1 & Robert B. Payne2,3
1
Department of Biology, Boston University, Boston, Massachusetts 02215, USA
Museum of Zoology and 3Department of Ecology and Evolutionary Biology,
University of Michigan, Ann Arbor, Michigan 48109, USA
-  Femalesusethesesongstochooseboth
A growing body of empirical and theoretical work supports the
theirmatesandtheneststheyparasi/ze
plausibility of sympatric speciation , but there remain few
2
.............................................................................................................................................................................
1–3
examples in which all the essential components of the process
are well understood. The African indigobirds Vidua spp. are
host-specific brood parasites. Indigobird nestlings are reared
along with host young, and mimic the mouth markings of their
respective hosts4–6. As adults, male indigobirds mimic host
song4–7, whereas females use these songs to choose both their
mates and the nests they parasitize8. These behavioural mechanisms promote the cohesion of indigobird populations associated with a given host species, and provide a mechanism for
reproductive isolation after a new host is colonized. Here we
show that all indigobird species are similar genetically, but are
significantly differentiated in both mitochondrial haplotype and
nuclear allele frequencies. These data support a model of recent
sympatric speciation. In contrast to the cuckoo Cuculus canorus,
in which only female lineages are faithful to specific hosts9,10, host
switches have led to speciation in indigobirds because both males
and females imprint on their hosts8,11.
-  Providesmechanismforreproduc/ve
isola/onaQeranewhostiscolonized
Figure 1 Examples of morphological variation between indigobird species. Nestling
mouth markings in V. camerunensis (a) and V. chalybeata (b) mimic the young of their
firefinch hosts, L. rara and L. senegala, respectively. Dark wing and plumage31
in V.
chalybeata from West Africa (c). Pale wing and green plumage in V. raricola (d). White bill
Sorensenetal.2003
GeographyofSpecia/on
Viewingmodesofspecia/onalongacon/nuum
GeographicModesofSpecia/on
sympatric
allopatric/
peripatric
parapatric
Very
low
Exchangeofindividuals
(geneflow)
Very
high
32
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