Personality Influences Risk of Parasitism in Fish.

Area of Science:

• Ecology
• Parasitology
• Animal Behavior

Background:

• The influence of host personality on parasite infection dynamics is an understudied area in host-parasite interactions.
• Individual variation in behavior, such as boldness and shyness, may affect exposure to infectious agents.

Purpose of the Study:

• To investigate the relationship between fish personality (bold vs. shy) and infection rates by the trematode Diplostomum pseudospathaceum.
• To determine if individual differences in parasite burden are consistent across successive infections.

Main Methods:

• Experiments were conducted using young-of-the-year Oncorhynchus mykiss (rainbow trout) as the second intermediate host.
• Fish were exposed to cercariae of the trematode Diplostomum pseudospathaceum.
• Infection rates and parasite burdens were assessed, with repeated infections to test for persistence.

Main Results:

• A positive correlation was observed between the outcomes of consecutive infections, indicating persistent individual differences in susceptibility.
• More active ('bold') fish exhibited different infection rates compared to less active ('shy') fish.
• Parasite accumulation with successive infections led to an aggregated distribution of D. pseudospathaceum among hosts.

Conclusions:

• Persistent individual differences in parasite burden among fish influence their vulnerability to infection and predation.
• Parasites play a significant role as a selective pressure in natural fish populations.
• Host personality is a crucial factor modulating host-parasite interactions and population dynamics.