1. Is host specificity the cause or the consequence
of parasite diversification:
lessons from the population genetics of lice and
helminths
Štefka, Jan1,2
1Natural History Museum, Cromwell Road, London, UK
2Faculty of Science, University of South Bohemia and Biology Centre ASCR,
České Budějovice, CZ

2. 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

3. Timescale: long vs. short evolutionary periods
Estimate the amount of co-speciations vs. host switches

4. 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 and
population histories…)

5. The importance of geography
Štefka et al, in prep.

6. traditional taxonomy
mtDNA phylogeny
N. parvulus
N. melanotis
N. trifasciatus N. macdonaldi

7. traditional taxonomy
mtDNA phylogeny
N. parvulus
N. melanotis
N. trifasciatus N. macdonaldi

8. Myrsidea sp.
98 specimens, 37 haps
N. trifasciatus
N. parvulus
N. trifasciatus
N. melanotis
N. macdonaldi

9. Analges sp. (Acari, Astigmata)
87 specimens, 71 haps
N. parvulus
N. trifasciatus
N. melanotis
N. macdonaldi

10. 7.000 YA
approx. 2-3 MYA
approx. 5 MYA
5-9 MYA

11. 7.000 YA
approx. 2-3 MYA
approx. 5 MYA
5-9 MYA
Progression rule

12. Polyplax serrata
genus Apodemus

13. Michaux et al., 2003, 2005
?
A. sylvaticus
A. flavicollis

14. northern border of A. sylvaticus range
A. sylvaticus A. flavicollis A. agrarius A. uralensis

15. A
A. flavicollis
A. sylvaticus
colonization
COI vs.
Haplotypes B duplication ?
+
EF1α
A. flavicollis
C A. agrarius
A. uralensis
Štefka and Hypša, 2008
Martinů et al, in prep.

16. A
colonization
B
molecular dating
-Clade A/B 1.5 Mya (1.4-1.6)
-Hosts Af/As 4 Mya
A
duplication
B Host specificity arose in allopatry

17. Ligula intestinalis s.l.

19. A
Tunisia
Sympatric lineages,
different host. spec.
B
Mutual def. hosts Tunisia
COI+COB
haplotypes
Bouzid et al, 2008, Int. J. Parasitol.
Bouzid et al, in prep.

20. Structure 2.2; 338 tapeworms
Europe Europe/Gobio TunisiaAlgeria/Barbus
X
Compatible with mtDNA Lake Tana
(Ethiopia)
B. humilis B. tsanensis
B. intermedius
B. brevicephalus
Štefka et al., 2009, Mol. Ecol.

21. Conclusions
• Host specificity arose in allopatry in P. serrata
• More complex picture in L. intestinalis: some lineages arising in
allopatry vs. ongoing host-dependant speciation in others.
• Host specificity is at least in some cases a product of speciation
processes not the motor of speciation in parasites.

22. Václav Hypša
Thanks to: Faculty of Science, USB, Č. Budějovice
Czech Rep.
Jana Martinů
Faculty of Science, USB, Č. Budějovice Vince Smith
Czech Rep. Entomology Dept., NHM, London
UK
Wafa Bouzid
Université P. Sebatier, Toulouse
France
Acknowledgements:
This work was supported by Grant Agency of the Czech Republic (project
No. 206/08/1019) and by Marie Curie Fellowship (project Galápagos, no.
235123, FP7-PEOPLE-IEF-2008).