Personality

Overview
 
 
Personality differences are widespread throughout the animal kingdom and represent individual behavioral variations that are consistent over time. They determine the way animals react to novel and challenging situations which affect resource acquisition, social interaction, survival and reproduction. Personalities have been well described and studied in freshwater fish and evaluated relative to ecological differences. However, despite important ecological and evolutionary consequences, nothing is known about personality variation in sharks and other large marine fishes. Recently we have begun a collaborative research project that combines long-term field and genetic data with modern analytical and ecological techniques to examine the causes and consequences of personality in a large marine fish, the lemon shark, Negaprion brevirostris.
  1. Underlying pattern of between-individual variation in behaviors (personalities) and between-individual correlations in behaviors (behavioral syndromes): Which captive trials will reveal personality: exploration of a novel environment or object, social interaction, reaction to frightening stimulus?  Are these different personality traits related to each other, demonstrating behavioral syndromes? Do captive personality traits reflect behavior in the wild?
  2. Ecological correlates of personality variation: How do differences in prey and predator distribution and abundance shape variation in juvenile lemon shark personality? Are dietary preferences associated with personality traits?  
  3. Association between personalities and variation in life-history traits and fitness: Is personality heritable? How do mortality and growth of juvenile lemon sharks correspond to behavioral types or syndromes? Does this correspondence change over ontogeny and/or ecological conditions?

The recent boom in personality studies comes from its far reaching implications for both ecology and evolutionary biology. While the importance of biodiversity and genetic diversity have long been considered as key factors for conservation and population management, until recent behavioral diversity has not been given the same importance. This late discovery of behavioral diversity in animal populations is strongly related to behavioral evolutionary theory. Indeed it has always been thought that natural selection will push towards an optimal behavior leading to the reduction of diversity. However, personality framework implies that natural selection creates and maintains this behavioral diversity. Neglecting this fact could have tremendous impact on conservation. For instance, it has been shown that regular fishing techniques can select for bolder, fast growing and reproductive individuals leaving slow growing and slow recovering populations. Therefore, understanding the causes and consequences of behavioral diversity / personality should become a priority in future conservation plans.

Investigating the causes (i.e. genetics, environment and experience) and consequences (i.e. growth and survival) of personality demands a lot of experimentation. We have designed a series of experiments that enable us to assess six sharks for sociability and exploration per day (Research Techniques - Captive Experiments):
  1. In 2012 we tested 121 individual juvenile lemon sharks (range 60-100 cm, total length) 80 of whom underwent repeated tests.  
  2. Preliminary analyses indicate that juvenile lemon sharks from two nurseries in Bimini show repeatability in their activity in a novel environment and in sociality.
  3. We also identified a behavioral syndrome in juvenile lemon sharks from one nursery in which activity and sociality were negatively correlated (r = -0.4, n = 48; Fig 1). This is the first demonstration of behavioral syndromes in chondrichthyan fishes (see figure below).

Michael Scholl, CEO of the Save Our Seas Foundation, created this aerial montage of our shark holding pens in North Sound nursery and the ensuing video analysis that takes place back in the lab. We created these pen to conduct observational experiments on shark social behavior and to determine personality traits like boldness or shyness within individual sharks.  

Wilson ADM, Krause J (2012) Personality and metamorphosis: is behavioral variation consistent across ontogenetic niche shifts? Behavioral Ecology doi: 10.1093/beheco/ars123
 
Wilson ADM, Krause S, Dingemanse NJ, Krause J (2012) Network position: a key component in the characterization of social personality types. Behavioral Ecology and Sociobiology 67:1: 163-173
 
Dingemanse NJ, Dochtermann NA (2013) Quantifying individual variation in behavior: mixed-effect modeling approaches, Journal of Animal Ecology 82: 39-54.
Principal Investigator
Jean Sebastien Finger - Humboldt University, DE
 
MSc Project Student
Clement Chazot - ISARA Institution of Agriculture, Food and Environment, Lyon FR
Felicie Dhellemmes- University of ISA Lille, FR
 
Collaborators
Dr. Samuel H Gruber - University of Miami, US
Dr. Tristan Guttridge - Cardiff University, UK
Dr. Demian Chapman - Stony Brook University, US
Prof. Jens Krause - Humboldt University, DE
Dr. Ned A Dochtermann - North Dakota State University, US
Dr. Nigel Hussey - Windsor University, CA
Dr. Alexander DM Wilson  - Humboldt University, DE
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