The majority of animals restrict their behavioural activity to defined times during the 24-hr day. This temporal niche is specified by an intricate interplay between the animal’s circadian clock and external factors like preferred temperature, light intensity, predators and food availability. Being active at the ‘wrong time’ can have severe impact on an organism’s fitness. But can animals actively choose their preferred temporal niche, and do individuals of the same species and population differ in their choice?
It is conceivable that ‘exploring’ or extending an individual’s temporal niche can have positive fitness effects. For example, extending individual activity outside of the original temporal niche may allow access to food sources not available to ‘conservative’ conspecifics. Also, changing environmental conditions likely change the conditions of temporal niches, which may activate niche conformance and/or choice mechanisms.
In this project, we test the hypothesis that individuals can actively explore and choose temporal niches that support their own fitness. We designed a behavioural choice apparatus (see Figure), allowing flies to choose between temporal regimes. Using flies with altered circadian clock speed, we will first analyse if flies can actively seek an environment in which external and internal time match. This proof-of-principle experiment will then be modified to test if individual wild type flies differ in their choice for diverse natural environmental conditions. By monitoring mating attempts and success, these assays may help to understand if individual variation in temporal niche choice leads to fitness gain in a changing environment (e.g. global warming).
To understand the cellular and molecular mechanisms underlying individual behavioural variation and temporal niche choice, and the potential role of cryptic genetic variation (CGV), we will investigate if the candidate evolutionary capacitator HSP90 contributes to behavioural variation among individuals. In summary, we aim to proof the existence of temporal niche choice for individual fitness gain. In addition, our novel approach will target the cellular and molecular mechanisms underlying temporal choice, which have not been described for any system.