Do brain parasites alter host personality? — Experimental study in minnows

Behav Ecol Sociobiol (2014) 68:197–204 DOI 10.1007/s00265-013-1634-2

ORIGINAL PAPER

Do brain parasites alter host personality? — Experimental study in minnows Jukka Kekäläinen & Yi-Te Lai & Anssi Vainikka & Ilkka Sirkka & Raine Kortet

Received: 3 July 2013 / Revised: 10 September 2013 / Accepted: 11 September 2013 / Published online: 22 September 2013 # Springer-Verlag Berlin Heidelberg 2013

Abstract Despite that the existence of animal personalities is widely recognized, no consensus has been reached on the relative importance of different ecological factors behind their expression. Recently, it has been suggested that parasites may have a crucial role in shaping animal personalities, but only a very few studies have experimentally tested the idea. We infected Eurasian minnows (Phoxinus phoxinus ) with the brain-encysted trematode parasite, Diplostomum phoxini , and studied whether infection could modify the personality of their hosts. Our results show that D. phoxini infection did not affect the mean levels of boldness, activity or exploration, but infected minnows showed higher repeatability in boldness and activity, and reduced repeatability in exploration. We also found that D. phoxini may be able to break the associations (behavioral syndromes) between behavioral traits, but that this effect may be dependent on parasite intensity. Furthermore, the effect of D. phoxini infection on personality of the hosts was found to be nonlinearly dependent on infection intensity. Taken together, our results suggest that D. phoxini parasites may shape the personality of their hosts, but that behavioral consequences of ecologically relevant infection levels may be rather subtle and easily remain undetected if only the mean trait expressions are compared. Keywords Activity . Boldness . Exploration . Parasite . Personality . Phoxinus phoxinus

Communicated by J. Lindström J. Kekäläinen (*) : Y.1). Variation in behavioral trait-specific loadings was relatively low: the difference between highest and lowest loadings was always