Related Experiment Videos
Host manipulation by Ligula intestinalis: accident or adaptation?
S P Brown1, G Loot, B T Grenfell
1Department of Zoology, University of Cambridge, UK. brown@isem.univ-montp2.fr
Parasitology
|November 27, 2001
Summary
Parasitic manipulation of fish hosts, like Ligula intestinalis in roach, alters behavior for transmission. Larger parasites have a greater impact, suggesting adaptive strategies.
Area of Science:
- Parasitology
- Behavioral Ecology
- Evolutionary Biology
Background:
- Complex life-cycle parasites often manipulate host phenotypes to increase transmission.
- Distinguishing adaptive manipulation from incidental infection effects is crucial.
Purpose of the Study:
- To investigate the impact of the macroparasite Ligula intestinalis on the behavior of its intermediate fish host, roach (Rutilus rutilus).
- To differentiate between adaptive host manipulation and incidental effects of infection.
Main Methods:
- Utilized field data from a natural system.
- Applied statistical and analytical tools, including generalized linear models.
- Employed game-theoretic models to explore adaptive manipulation strategies.
Main Results:
- Both the presence and intensity of Ligula intestinalis infection significantly altered roach behavior.
- Infected fish exhibited a preference for the lake-edge during autumn.
- Parasite size influenced the host's behavioral modification, with larger parasites having a disproportionate effect.
Conclusions:
- Ligula intestinalis actively manipulates roach behavior, favoring transmission.
- Parasite size-dependent manipulation offers a potential evolutionary strategy.
- The findings challenge the 'incidental effect' hypothesis, highlighting functional impacts of parasites.