A. (Apu) Ramesh, PhD

Eco-evo-devo of animal personalities

The existence of animal personality (consistent individual differences in behaviours across contexts) and behavioural syndromes (correlations among personality traits) is intriguing, since one would expect that flexible behavioural response is selectively favoured. Understanding syndromes is therefore important. An excellent example is the migration syndrome found in many species. In many animal populations individuals differ considerably in their migration tendency. The extreme case is ‘partial migration,’ where only a fraction of the population migrates. Migrants often represent a non-random subset of the population that differ consistently in sets of phenotypic features (morphology, physiology, behaviour). Individual differences in this ‘migration syndrome’ are ideal to study the emergence of individual variation from both a mechanistic and an evolutionary perspective.

I use three-spined sticklebacks (Gasterosteus aculeatus) to study this as there are populations exhibiting no, partial and total migration in the river systems of the Netherlands. In addition, there are land-locked populations, allowing us to draw robust conclusions about divergence of syndromes within and between populations. Apart from field studies, I also conduct experiments in semi-natural connected pond systems which allows control over environmental variables allowing for causal relationships regarding emergence of syndromes to be established. The empirical studies will be complemented by theoretical modelling to derive testable predictions and to provide a framework for interpreting the empirical results. Together this will provide a deeper understanding of three intriguing basic biological phenomena: individual differences, behavioural syndromes and partial migration.