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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.