Personality differences in two minnow populations that differ in their parasitism and predation risk

Raine Kortet,Yi-Te Lai,Jukka Kekã¤Lã¤Inen,Ilkka Sirkka,Anssi Vainikka

doi:10.3389/fevo.2015.00009

Abstract

Animals are often individually consistent in their behavior, not only over time, but also across different functional contexts. Recent research has focused on phenotypic and evolutionary mechanisms explaining such personality differences through selection. Parasitism and predation induce important mortality and fitness costs, and are thus the main candidates to create and maintain personality differences in the wild. Here, we present data on the behavioral consistency of the Eurasian minnow (Phoxinus phoxinus) from two populations that live in different tributaries of the same river, but whose ecological environment differs fundamentally with regard to predation and parasitism. We experimentally demonstrate that minnow in both study populations are consistent in their boldness and activity. However, the two study populations differ notably: in the high predation and parasitism risk population fish show higher mean boldness, but tend to be less active than fish in low predation and parasitism risk population. Parasite (Diplostomum phoxini) load was negatively, but not statistically significantly, associated with fish activity level. Our study suggests that parasitism and predation are likely important agents in the ecology and evolution of animal personalities.

Highlights

Over the last decade there has been considerable interest in animal personalities (e.g., Bell, 2007; Sih et al, 2012; Carere and Maestripieri, 2013; Kortet et al, 2014)
In our previous experimental work, we have demonstrated that minnows infected by the trematodean parasite Diplostomum phoxini show higher repeatability in boldness and activity, and reduced repeatability in exploration compared to non-infected fish (Kekäläinen et al, 2014a)
We found that minnow were individually consistent in boldness and activity in both of the study populations, while the populations did not differ in the repeatability of behavior

Summary

Introduction

Over the last decade there has been considerable interest in animal personalities (e.g., Bell, 2007; Sih et al, 2012; Carere and Maestripieri, 2013; Kortet et al, 2014). Several mechanisms have been proposed to explain how personality variation is maintained in animal populations over evolutionary time These mechanisms include, for example, the asset protection principle, i.e., behaviorally mediated trade-offs between current vs future reproduction (Wolf et al, 2007), related growth-mortality trade-offs (Stamps, 2007; Biro and Stamps, 2008), positive feedback loops and state-dependent behavior (McElreath et al, 2007; Luttbeg and Sih, 2010) and variation in costly cognition (Niemelä et al, 2013). These mechanisms are not necessarily mutually exclusive. They are based on additive and interacting environmental factors such as predation and parasitism that affect the costs and benefits of certain behaviors in various ways

Objectives

Methods

Results

Conclusion