Experience and dominance in fish pairs jointly shape parasite avoidance behaviour

摘要: There is increasing evidence that the composition of a social group influences fitness its members. For example, member identities can determine exposure risk to contact-transmitted parasites and consequently impact health all Here, we propose may also affect host parasite propagules prevailing in environment via collective avoidance behaviours. We explored spatial trematode parasite, Diplostomum pseudospathaceum, using simplest form groups, pairs sea trout, Salmo trutta trutta. These showed either (1) between-group heterogeneity their experience with (both, one or neither previously exposed) matched dominance ranks (assessed through growth rates) (2) within-group previous ranks. show had recently been exposed spent significantly less time areas infection than which both individuals were unexposed. This result suggests improves avoidance. Among mixed history, was most pronounced when individual dominant over partner. conclude higher ranked direct movements history predicts pair's As efficiency directly related rate, our results suggest shape nonsocially transmitted parasites, ultimately fitness.