I have always wondered why different animals behave the way they do because they seem to differ strikingly in character and temperament. Not just that, animals within a single population also seem to act differently from one another. Thanks to scientific studies, I will soon find answers to my barrage of questions. Just recently, it has become evident that personalities are a widespread phenomenon in the animal kingdom. Animals as diverse as spiders, mice and squids appear to have personalities. Personality differences have been described in more than 60 species, including primates, rodents, birds, fish, insects and mollusks.
Why do different personality types exist within a single population given that, at first sight, one would expect one type to be more successful than another? Why are individuals not more flexible considering that personality rigidity sometimes leads to seemingly inefficient behaviour? Why do we find the same types of traits correlated with each other in very different kinds of animals?
New work by Max Wolf (University of Groningen; currently at the Santa Fe Institute), Santa Fe Institute Postdoctoral Fellow Sander van Doorn, Franz Weissing (University of Groningen), and Olof Leimar (Stockholm University) offers an explanation for the evolution of animal personalities.
Max Wolf et al argue that in many cases, personalities are shaped by a simple underlying principle: the more an individual stands to lose (in terms of future reproduction) the more cautiously it is likely to behave, in all kinds of situations and consistently over time.
They begin with two basic observations. Firstly, variation in personalities is often structured according to differences in the overall willingness to take risks. Secondly, individuals are often confronted with a trade-off between current and future reproduction: the more an individual currently invests in reproduction, the less the resources left to invest in future opportunities, and vice versa.
Method
The authors use a mathematical model to demonstrate that this fundamental trade-off can give rise to populations where some individuals put more emphasis on future reproduction than others. Individuals who invest in future reproductive success eventually evolve into risk-aversive beings in different behavioural contexts (e.g. encounters with predators and aggressive interactions), whereas individuals who put emphasis on current reproductive success evolve a more risk-prone personality.
Via: Physorg
