Bayesian inference supports the host selection hypothesis in explaining adaptive host specificity by European...

Area of Science:

• Ecology
• Parasitology
• Evolutionary Biology

Background:

• Generalist parasites infect multiple host species, but temporal patterns of host specificity are understudied.
• Understanding these patterns is crucial for assessing parasite impact and evolutionary selection on hosts.

Purpose of the Study:

• To investigate the temporal dynamics of European bitterling (Rhodeus amarus) infection in four freshwater mussel species over three spawning seasons.
• To examine how host specificity changes throughout the bitterling spawning period.

Main Methods:

• A Bernoulli Generalized Additive Mixed Model with Bayesian inference was employed.
• Data were collected across multiple mussel populations over three years.

Main Results:

• The mussel species *Unio pictorum* was utilized throughout the entire European bitterling spawning season.
• As the season advanced, bitterling increasingly preferred other, less suitable mussel species.
• Shifts in host use correlated with density-dependent mortality in already infected preferred hosts.

Conclusions:

• European bitterling exhibit plasticity in host specificity, aligning with host selection hypotheses.
• This temporal host switching influences host population dynamics and imposes varying selection pressures.
• The bitterling-mussel interaction demonstrates unique temporal host dynamics compared to avian brood parasitism.