Is host specificity the cause or the consequenceof parasite diversification:

lessons from the population genetics of lice andhelminths

Štefka, Jan1,2

1Natural History Museum, Cromwell Road, London, UK2Faculty of Science, University of South Bohemia and Biology Centre ASCR, České Budějovice, CZ

Evolution of novel taxa in parasites:host specificity vs. geografic distribution.

• Host specificity and speciation in metazoan parasites– What is host specificity– Why bother– Established framework?

• Timescale: long vs. short evolutionary periods

Estimate the amount of co-speciations vs. host switches

Timescale: long vs. short evolutionary periods

Evolution of novel taxa in parasites:host specificity vs. geografic distribution.

• Speciation and host specificity

• Timescale: long vs. short evolutionary periods

• Careful choise of model taxa (complexity of life-cycles andpopulation histories…)

Štefka et al, in prep.

The importance of geography

N. trifasciatus N. macdonaldi

N. parvulus

traditional taxonomymtDNA phylogeny

N. melanotis

N. trifasciatus N. macdonaldi

N. parvulus

traditional taxonomymtDNA phylogeny

N. melanotis

Myrsidea sp.98 specimens, 37 haps

N. parvulus

N. melanotis

N. trifasciatus

N. macdonaldi

N. trifasciatus

Analges sp. (Acari, Astigmata)87 specimens, 71 haps

N. parvulus

N. trifasciatus

N. melanotis

N. macdonaldi

5-9 MYAapprox. 5 MYA

7.000 YA

approx. 2-3 MYA

5-9 MYAapprox. 5 MYA

7.000 YA

Progression rule

approx. 2-3 MYA

Polyplax serrata

genus Apodemus

A. sylvaticusA. flavicollis

?

Michaux et al., 2003, 2005

northern border of A. sylvaticus range

A. sylvaticus A. flavicollis A. agrarius A. uralensis

A. agrariusA. uralensis

A. flavicollis

A. flavicollisA. sylvaticus

colonization vs.

duplication ? COIHaplotypes+EF1α

A

B

C

Štefka and Hypša, 2008Martinů et al, in prep.

B

A

colonization

B

A

duplication

molecular dating-Clade A/B 1.5 Mya (1.4-1.6)-Hosts Af/As 4 Mya

Host specificity arose in allopatry

Ligula intestinalis s.l.

Tunisia

Tunisia

A

B

Sympatric lineages,different host. spec.

Mutual def. hosts

Bouzid et al, 2008, Int. J. Parasitol.Bouzid et al, in prep.

COI+COBhaplotypes

Europe/Gobio TunisiaAlgeria/BarbusEurope X

B. humilisB. intermediusB. tsanensis

B. brevicephalus

Compatible with mtDNA

Structure 2.2; 338 tapeworms

Štefka et al., 2009, Mol. Ecol.

Lake Tana(Ethiopia)

• Host specificity arose in allopatry in P. serrata

• More complex picture in L. intestinalis: some lineages arising inallopatry vs. ongoing host-dependant speciation in others.

• Host specificity is at least in some cases a product of speciationprocesses not the motor of speciation in parasites.

Conclusions

Acknowledgements:This work was supported by Grant Agency of the Czech Republic (projectNo. 206/08/1019) and by Marie Curie Fellowship (project Galápagos, no.235123, FP7-PEOPLE-IEF-2008).

Thanks to: Václav HypšaFaculty of Science, USB, Č. Budějovice Czech Rep.

Vince SmithEntomology Dept., NHM, London

UK

Wafa BouzidUniversité P. Sebatier, Toulouse

France

Jana MartinůFaculty of Science, USB, Č. Budějovice

Czech Rep.