Impacts of Selective Predation on Infection Prevalence and Host Susceptibility

Area of Science:

• Ecology
• Evolutionary Biology
• Parasitology

Background:

• Predation significantly influences ecological processes, including host-parasite interactions.
• Selective predation, where predators target specific prey, can alter prey populations and evolutionary pressures.
• While many studies focus on predators consuming infected prey, some predators preferentially consume uninfected individuals, impacting host-parasite dynamics differently.

Purpose of the Study:

• To investigate how different types of selective predation (on infected, uninfected, or random prey) affect host-parasite infection dynamics and host evolution.
• To understand the consequences of predator prey selectivity strategies on host fitness and parasite transmission.

Main Methods:

• Utilized a laboratory model system: Daphnia dentifera infected with the fungus Metschnikowia bicuspidata.
• Artificially manipulated selective predation by removing infected, uninfected, or randomly selected prey over 8-9 generations.
• Monitored population demographics, infection prevalence, and host susceptibility weekly and post-experiment.

Main Results:

• No significant differences in host abundance or overall infection prevalence were observed across predation treatments after 6 weeks.
• Counterintuitively, populations with selective predation on infected individuals showed a higher abundance of infected hosts.
• Populations with selective predation on uninfected individuals exhibited increased host susceptibility to infection after standardized parasite exposure.

Conclusions:

• Selective predation strategies can unexpectedly alter infected host abundance and influence host evolution.
• Predators preferentially consuming uninfected prey may inadvertently increase disease prevalence and drive adaptive evolution in host populations.
• Understanding predator selectivity is crucial for predicting host-parasite dynamics and evolutionary trajectories.