Lac Hertel

Fussmann Lab
Department of Biology

Brachionus LogoTrinidadBrachionus Logo

Funded through an NSERC-SRO grant we are studying eco-evolutionary dynamics in the field, with organisms that are embedded in their natural environment.

Ecology and evolution of parasite-host relationships in streams in Trinidad

Guppy Guppies (Poecilia reticulata) in a Trinidad stream © Paul Bentzen

The theme

Parasite infections shape the evolution and ecology of fishes, but we have little understanding of how rapidly changes in parasite levels lead to changes in populations, communities and ecosystems. We now start to investigate these questions through collaboration with a FIBR research initiative funded by the National Science Foundation (NSF) of the United States.

This NSF project involves experimental manipulations of whole stream ecosystems on the tropical island of Trinidad. In particular, guppies (a small and prolific freshwater fish) will be introduced from streams characterized by high predation and parasitism into formerly guppy-free streams characterized by low predation and parasitism. Very detailed monitoring by the NSF team following this introduction will enable a detailed investigation of the speed of evolutionary change in the guppies and any consequences for interacting species and for the ecosystem. The NSF project focuses entirely on the effects of predation, whereas we will add the parasite dimension.

Worm Gyrodactylus, dominant ectoparasite of guppies (picture courtesy of Joanne Cable)
The questions
  • How do interactions between fish and their parasites and predators influence evolution and ecology in whole stream ecosystems?
  • What are the infection levels of guppies in relation to predation regime, genetic diversity and parasite species across sites in Trinidad?
  • How do resistance and tolerance against parasite infections evolve?
  • Are survival, resistance and tolerance to parasites related to particular patterns of molecular genetic variation?
Guppy Colourful guppies on a measuring grid © Andrew Hendry
The system

We combine four major research approaches: field surveys, field experiments, lab assays, and genetic analyses (microsatellites and MHC Class IIB alleles).

The field research takes place in Trinidad. The focal organisms are guppies (Poecilia reticulata) that live in streams at varying levels of predation pressure and parasite infection. Their dominant parasites are two species of a monogenean ectoparasite of the skin and fins, Gyrodactylus turnbulli and Gyrodactylus bullatarudis.


Andrew fishing The Trinidad field team: Felipe D, Gregor, Andrew, Lari, Felipe P., Paul, Ian Paterson (Paul's tech) © Andrew Hendry
The people

This is a collaborative research project between McGill University (Prof. Andrew Hendry, Prof. Marilyn Scott, Prof. Gregor Fussmann), Dalhousie University (Prof. Paul Bentzen) and the FIBR Guppy project with its PI Prof. David Reznick.

Grad students Felipe Dargent and Felipe Pérez-Jvostov have started on the project in Sept. 2008; Lari Delaire joined us in Jan. 2009. Lyndsey Baillie started in May 2009 as an MSc student in the Bentzen lab at Dalhousie.

Senior research scientist Dr. David Marcogliese (Environment Canada) and Prof. Indar Ramnarine are advisors and student committee members on this project.


Guppy ... and more guppies © Paul Bentzen
The funding