Coevolution Session 1f Evolution Meetings – Chico 2003.

Coevolution

Session 1f

Evolution Meetings – Chico 2003

Ancient Mariners & Recent Stowaways:

the coevolution of seabirds & their lice

Division of Environmental and Evolutionary BiologyInstitute of Biomedical and Life Sciences

Graham Kerr BuildingUniversity of Glasgow

Scotland

Vincent S. Smith & Roderic D.M. Page

Parasites… ancient associates or recent acquisitions?

time

Cospeciation

Extinction

In situ radiation

Serial colonisation

Recent colonisation

Diversification byhost switching

Host

ParasiteTime is

important!

The Hosts & Parasites

Feather lice(Insecta: Phthiraptera)

Tubenose seabirds(Aves: Procellariiformes)

Tubenose seabirds are very lousy!

Ischnocera

Charadriiformes

Procellariiformes

Num

ber

of lo

use

spec

ies

Proce

llariif

ormes

Charadriif

ormes

0

1

2

3

4

5

6Ischnocera

Analysis

ii. Rates smoothing• nonparametric rate smoothing using r8s (Sanderson, 2003)• perform on 100 trees drawn from Bayesian chain

iii. Calibration• assume that cospeciating host/parasites are likely to be the same age• penalised likelihood to estimate the relative age of the other nodes

i. Host/parasite phylogenies• mitochondrial 12s rRNA, COI & Cyt. B• Bayesian analysis (trees sampled every 1000 generations after ‘burnin’)

Albatross-louse cophylogeny

0.01

Macronectes giganteus

Diomedea epomophora

Diomedea exulans

Diomedea gibsoni

Diomedea antipodensis

Phoebastria nigripes

Phoebastria irrorata

Thalassarche chrysostoma

Thalassarche melanophris

Thalassarche cauta

Thalassarche bulleri

Phoebetria palpebrata0.1

Paraclisis obscura

Paraclisis hyalina NZ AP16

Paraclisis hyalina FD03

Paraclisis hyalina GLA901

Paraclisis hyalina GLA896

Paraclisis confidens

Paraclisis miriceps

Paraclisis diomedeae FD07


Paraclisis diomedeae GLA529

Paraclisis diomedeae NZ AP21


Hosts:Albatrosses

Parasites:Feather Lice

Page et al (in press)Mol. Phyl. Evol.

Analysis

v. Tree mapping• identify comparable nodes in the host & parasite tree• compare ages of nodes

ii. Rates smoothing• nonparametric rate smoothing using r8s (Sanderson, 2003)• perform on 100 trees drawn from Bayesian chain

iii. Calibration• assume that cospeciating host/parasites are likely to be the same age• penalised likelihood to estimate the relative age of the other nodes

iv. Sensitivity analyses• rate smoothing is sensitive to choice of smoothing parameter • we varied the log of the parameter for each of the 100 bird/louse trees

i. Host/parasite phylogenies• mitochondrial 12s rRNA, COI & Cyt. B• Bayesian analysis (trees sampled every 1000 generations after ‘burnin’)

Procellariiform-louse tanglegram

0.1 substitutions per site



Diomedea exulans

1.00

1.00

1.00

Pelagodroma marina

0.60


Daption capense

1.00

Puffinus gravis

Puffinus griseus

1.00

Puffinus pacificus

1.00

Puffinus huttoni

0.96

Calonectris diomedea

1.00

Procellaria westlandica

1.00

Pelecanoides georgicus

Lugensa brevirostris

Pachyptila vittata

Pachyptila turtur

1.000.60

0.94

0.33

Pterodroma inexpectata

Pterodroma cooki

1.00

0.44

1.00

0.95

Paraclisis diomedeae


Paraclisis hyalina

Paraclisis hyalina1.00

Paraclisis obscura 1.00

1.00

0.99

Perineus concinnoides

Harrisoniella hopkinsi

1.00

0.77

Pelmatocendra enderleini

0.35

Halipeurus pelagicus

Halipeurus diversusHalipeurus gravis

Halipeurus spadix0.82

Halipeurus abnormis

Halipeurus consimilis

1.00

0.99

0.73

0.98

0.70

Naubates harrisoni

Naubates fuliginosus 1.00

1.00

Pseudonirmus gurlti

1.00

Naubates pterodromi 0.69

0.30

0.18

Bedfordiella unica

1.00

0.1 substitutions per site

Diomedea epomophora

Halipeurus turtur

Naubates prioniNaubates prioni

0.67

Bayesian inference(12s rRNA, COI & Cyt. B)

Are procellariformlice as old as their hosts?

• Age estimates relatively constant across a range of smoothing parameters

• Radiation of procellariform lice is slightly more recent than that of their hosts

log 10 smoothing

3

2 .5

2

1 .5

1

0 .5

0

0 0 .5 1 1 .5 2 .52 3

Procellariiformesre

lativ

e a

ge

Procellariform birds 2-2.5 times older than albatrosses

0

3

2 .5

2

1 .5

1

0 .5

0 0 .5 1 1.5 2 .52 3

Feather lice

log 10 smoothing

rela

tive

ag

e

Feather lice 1.75-2.25 times older than albatross lice

Bird-Louse Ages



Diomedea exulans

Diomedea epomophora

Pelagodroma marina


Daption capense



Pachyptila vittata

Pachyptila turtur


Pterodroma cooki

Pygoscelis adeliae

Eudyptula minor

Gavia arctica

Gavia immer

Puffinus griseus

Puffinus gravis

Puffinus huttoni





Diomedea exulans

Diomedea epomophora

Pelagodroma marina


Daption capense



Pachyptila vittata

Pachyptila turtur


Pterodroma cooki

Pygoscelis adeliae

Eudyptula minor

Gavia arctica

Gavia immer

Paraclisis diomedeae


Paraclisis hyalina

Paraclisis hyalina

Paraclisis obscura

Naubates harrisoni

Naubates fuliginosus

Puffinus griseus

Puffinus gravis

Puffinus huttoni



Halipeurus pelagicus

Halipeurus diversus

Halipeurus gravis

Halipeurus spadix

Halipeurus abnormis

Halipeurus consimilis

Halipeurus turturi

Naubates prioni

Naubates prioni

Naubates pterodromi

Perineus concinnoides

Harrisoniella hopkinsi

relative age relative age123 0 0 1 2 0 1 2

• How do we account for this?

?

Relative Age of Host-Parasite Clades

0

0.5

1

1.5

2

2.5

0 0.5 1 1.5 2 2.5

Host Age

Lous

e A

ge

Petrels & Halipeurus

Procellariformes & Philoceanus-complex

• Lice ¾ of the age of their hosts!

• i.e lice are slightly younger than we might expect if they are “cospeciating”

Conclusions

i. Is this discrepancy real?• Are the assumptions behind the calibration point correct

Calibration Correction?Hosts:Albatrosses

Parasites:Feather Lice

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0.02 0.04 0.06 0.08 0.1 0.12

Host divergence

Lou

se d

iver

gen

ce Delayed cospeciation

i.e. Paraclisis speciating slightly after their hosts

Conclusions

iii. Do we need to redefine “cospeciation”• Is the expectation of temporal congruence always correct in

cospeciating lineages?

i. Is this discrepancy real?• Are the assumptions behind the calibration point correct

ii. If it is real, what does it mean?• Gene flow briefly persists between lice after speciation of the host?• Failure of lice to speciate (Johnson et al, 2003)• Aren’t we really dating gene coalescent times anyway?

(Rannala & Michalakis, 2002)

Acknowledgements

• Martyn Kennedy & Rob Cruickshank

• Wellcome Trust

Coevolution Session 1f Evolution Meetings – Chico 2003.

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Transcript of Coevolution Session 1f Evolution Meetings – Chico 2003.