Individuals differ. This seemingly trivial statement has nevertheless led to paradigm shifts, as three different fields of organismal biology have seen a marked change in key concepts over the last years.
- In behavioural biology, it has been realised that there are profound differences between individuals and that these can be stable over time and across contexts, giving rise to the concept of animal personalities.
- In ecology, an increasing focus is likewise on the considerable variation in the ecological niche realised by species, populations, and even individuals.
- In evolutionary biology, where individual variation has always been central, there is an increasing awareness of the complexity with which genotypes interact with the environment to produce unique phenotypes.
As a consequence, a concept of an individualised niche is needed, rather than focusing only on a mean value for a given population. Currently, the short-term behavioural processes of phenotypic adjustment within the lifetime of individuals, as addressed by behavioural biology, are not sufficiently put into context with evolutionary processes, which are often studied in rather simplified systems where genetic variability more directly influences the phenotype.
Moreover, whereas initially the ecological time scale was deemed to be fundamentally different from the evolutionary time scale, this notion has recently been replaced by a more integrative one, where evolution can indeed happen over ecological time scales. While in each of these fields, the concept of individualisation has contributed to major scientific knowledge increase, we currently lack sufficient cross-fertilisation.
Therefore, our central research goal is to redefine the niche concept on the individual level. By doing so, we want to gain a comprehensive understanding of how individual phenotypes interact with their environment and what the ensuing consequences for ecological and evolutionary processes are. We hypothesise that, across taxa, the interaction between the individualised phenotype and the environment results in individualised niches via three mechanisms of adjustment and adaptation: niche choice, niche conformance and niche construction.
The implications of such a novel synthesis of individualisation would be of paramount importance for behaviour, ecology and evolution alike. We are convinced that the time is right to achieve just that: We hence propose to combine behaviour, ecology and evolution in an etho-eco-evo approach to develop a novel synthesis of individualisation that also takes into account that the environmental conditions change throughout an animal's lifetime. Our approach will lead to an unprecedented understanding of how and why individuals only realise a tiny subset of the species? niche and what the implications are for both ecological adjustment and evolutionary adaptation in a rapidly changing world.