What it Takes to Be a Fish: Behavioural Patterns, Mechanisms and Implications of Inter-Individual Variations in Personality and Cognition in Wild Zebrafish

Daniel, Danita Kripa (2022) What it Takes to Be a Fish: Behavioural Patterns, Mechanisms and Implications of Inter-Individual Variations in Personality and Cognition in Wild Zebrafish. PhD thesis, Indian Institute of Science Education and Research Kolkata.

Text (PhD thesis of Danita Kripa Daniel (16RS040)) 16RS040.pdf - Submitted Version Restricted to Repository staff only Download (6MB)

Abstract

Variations in a myriad of different traits are present at every level of organization across taxa. Within a species, variations are present between populations from different habitats and even between and within individuals of the same population, increasing adaptive advantages in a wide range of environmental conditions. Interindividual variations have been found in many traits, but are most easily quantified and compared for behavioural characteristics. Studies have shown that individuals could differ from each other in a variety of behavioural traits, and if these variations are consistent and repeatable, they constitute the personality of the organism. Since most behavioural traits, including cognitive behaviours show such variations, the interplay between personality and cognition related behaviours, their co-occurrence and the adaptive implications of behavioural patterns becomes a fascinating area of study that can elucidate some of the factors that govern the evolution of complex behaviours. Although the zebrafish is a popular model organism in many fields of biology, its behaviour has not been studied from an evolutionary perspective. Our study has used multiple populations of wild-caught zebrafish to examine consistencies within personality and cognition related traits, as well as correlations between them. We have also aimed to test for the effect of both personality and cognition on complex behaviours such as decision making in an attempt to understand how these traits interact with each other. The underlying neurological mechanisms that could govern patterns in interindividual variations have also been studied from a functional (behavioural lateralization) as well as structural (brain size and morphology) perspective. Since we found that the patterns of variations and correlations in behaviour were consistent for multiple populations and for different kinds of behaviours, we then performed tests to study the implications and consequences of these patterns. We tested for behavioural plasticity in the presence of a predator, effect of acute isolation stress, adaptation to varying habitats, effect of long-term lab maintenance, effect of testing conditions and mate preference, all with respect to interindividual variations and correlations between personality and cognitive ability. Overall, our study explained consistency in behavioural patterns at various scales and the importance of interindividual variation in populations, thus shedding light on the proximate and ultimate evolutionary forces that lead to variation.

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