Skip to main content
×
Home
    • Aa
    • Aa

Parasite variation and the evolution of virulence in a Daphnia-microparasite system

  • T. J. LITTLE (a1), W. CHADWICK (a1) and K. WATT (a1)
Abstract
SUMMARY

Understanding genetic relationships amongst the life-history traits of parasites is crucial for testing hypotheses on the evolution of virulence. This study therefore examined variation between parasite isolates (the bacterium Pasteuria ramosa) from the crustacean Daphnia magna. From a single wild-caught infected host we obtained 2 P. ramosa isolates that differed substantially in the mortality they caused. Surprisingly, the isolate causing higher early mortality was, on average, less successful at establishing infections and had a slower growth rate within hosts. The observation that within-host replication rate was negatively correlated with mortality could violate a central assumption of the trade-off hypothesis for the evolution of virulence, but we discuss a number of caveats which caution against premature rejection of the trade-off hypothesis. We sought to test if the characteristics of these parasite isolates were constant across host genotypes in a second experiment that included 2 Daphnia host clones. The relative growth rates of the two parasite isolates did indeed depend on the host genotype (although the rank order did not change). We suggest that testing evolutionary hypotheses for virulence may require substantial sampling of both host and parasite genetic variation, and discuss how selection for virulence may change with the epidemiological state of natural populations and how this can promote genetic variation for virulence.

Copyright
Corresponding author
*Corresponding author. Tel: +0131 650 7781. Fax: +0131 650 6564. E-mail: tom.little@ed.ac.uk
Linked references
Hide All

This list contains references from the content that can be linked to their source. For a full set of references and notes please see the PDF or HTML where available.

G. Almogy , N. Cohen , S. Stocker and L. Stone (2002). Immune response and virus population composition: HIV as a case study. Proceedings of the Royal Society of London, B 269, 809815.

J. B. Andre , J. B. Ferdy and B. Godelle (2003). Within-host parasite dynamics, emerging trade-off, and evolution of virulence with immune system. Evolution 57, 14891497.

H. J. Bremermann and J. Pickering (1983). A game-theoretical model of parasite virulence. Journal of Theoretical Biology 100, 411426.

J. J. Bull (1994). Virulence. Evolution 48, 14231437.

H.-J. Carius , T. J. Little and D. Ebert (2001). Genetic variation in a host–parasite association: Potential for coevolution and frequency dependent selection. Evolution 55, 11361145.

K. Choo , P. D. Williams and T. Day (2003). Host mortality, predation and the evolution of parasite virulence. Ecology Letters 6, 310315.

T. Day and S. R. Proulx (2004). A general theory for the evolutionary dynamics of virulence. American Naturalist 163, E40–.E63

J. C. De Roode , R. Pansini , S. J. Cheesman , M. E. H. Helinski , S. Huijben , A. R. Wargo , A. S. Bell , B. H. K. Chan , D. Walliker and A. F. Read (2005). Virulence and competitive ability in genetically diverse malaria infections. Proceedings of the National Academy of Sciences, USA 102, 76247628.

A. Duncan , S. E. Mitchell and T. J. Little (2006). Parasite-mediated selection in Daphnia: the role of sex and diapause. The Journal of Evolutionary Biology 19, 11831189.

C. Dye and C. R. Davies (1990). Glasnost and the great gerbil: virulence polymorphisms in the epidemiology of leishmaniasis. Trends in Ecology and Evolution 5, 237238.

D. Ebert (1998). Experimental evolution of parasites. Science 282, 14321435.

D. Ebert , H.-J. Carius , T. J. Little and E. Decaestecker (2004). The evolution of virulence when parasites cause host castration and gigantism. American Naturalist 164, s19s32.

D. Ebert , P. Rainey , T. M. Embley and D. Scholz (1996). Development, life cycle, ultrastructure and phylogenetic position of Pasteuria ramosa Metchnikoff 1888: rediscovery of an obligate endoparasite of Daphnia magna Straus. Philosophical Transactions of the Royal Society of London, B 351, 16891701.

F. Escriu , A. Fraile and F. García-Arenal (2003). The evolution of virulence in a plant virus. Evolution 57, 755765.

S. A. Frank (1996). Models of parasite virulence. Quarterly Review of Biology 71, 3778.

S. Gandon , M. J. Mackinnon , S. Nee and A. F. Read (2001). Imperfect vaccines and the evolution of pathogen virulence. Nature, London 414, 751755.

K. Grech , K. Watt and A. F. Read (2006). Host-parasite interactions for virulence and resistance in a malaria model system. Journal of Evolutionary Biology 19, 16201630.

K. N. Jensen , T. J. Little , A. Skorping and D. Ebert (2006). Empirical support for an optimal virulence in a castrating parasite. Plos Biology 4, e197. doi: 10.1371/journal.pbio.0040197.

T. Lefebvre , M. Sanchez , F. Ponton , D. Hughes and F. Thomas (2007). Virulence and resistance in malaria: who drives the outcome of infection. Trends in Parasitology 23, 299302.

M. Lipsitch and E. R. Moxon (1997). Virulence and transmissibility of pathogens: What is the relationship? Trends in Microbiology 5, 3137.

T. J. Little and D. Ebert (2000). The cause of parasitic infection in natural populations of Daphnia: the role of host genetics. Proceedings of the Royal Society of London, B 267, 20372042.

T. J. Little and S. C. Killick (2007). Evidence for a cost of immunity when the crustacean Daphnia magna is exposed to the bacterial pathogen Pasteuria ramosa. Journal of Animal Ecology 76, 12021207.

T. J. Little , K. Watt and D. Ebert (2006). Parasite-host specificity: experimental studies on the basis of parasite adaptation. Evolution 60, 3138.

M. J. Mackinnon and A. F. Read (1999). Genetic relationships between parasite virulence and transmission in the rodent malaria Plasmodium chabaudi. Evolution 53, 689703.

R. M. May and R. M. Anderson (1983). Epidemiology and genetics in the coevolution of parasites and hosts. Proceedings of the Royal Society of London, B 219, 281313.

I. Pagan (2007). The relationship of within-host multiplication and virulence in a plant-virus system. PLoS ONE 2, e786. doi: 10.1371/journal.pone.000786.

A. F. Read and L. H. Taylor (2001). The ecology of genetically diverse infections. Science 292, 10991102.

S. Sacristán , A. Fraile , MALPICA , J. M. and F. García-Arenal (2005). An analysis of host adaptation and its relationship with virulence in cucumber mosaic virus. Phytopathology 95, 827833.

A. D. Stewart , J. M. Logsdon and S. E. Kelley (2005). An empirical study of the evolution of virulence under both horizontal and vertical transmission. Evolution 59, 730739.

R. A. Weiss (2002). Virulence and pathogenesis. Trends in Microbiology 10, 314317.

Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Parasitology
  • ISSN: 0031-1820
  • EISSN: 1469-8161
  • URL: /core/journals/parasitology
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Keywords:

Metrics

Altmetric attention score