The circadian clock modulates many aspects of an animal’s behavior and physiology in a rhythmic manner. Most likely all animals have evolved a common timekeeping mechanism because of the selective pressure induced by daily and seasonal changes in the environment which they are living in.
Circadian rhythms, such as those in daily activity, are controlled by a master clock consisting of a network of clock neurons in the brain. The principle of molecular rhythm generation is similar between phylogenetically distant groups such as mammals and insects, though there are differences in the core clock components (Hardin, 2011). The same applies for the neuronal organization of the animal master clock in the brain. The brain clock is topographically and functionally structured in different parts containing populations of clock neurons that are heterogeneous in morphology, physiology and neurotransmitter content and fulfill slightly different functions. Per definition a clock neuron generates a self-sustained molecular rhythm through the interaction of clock genes and proteins. In D. melanogaster for example the key players of the molecular clockwork are per (PER), tim(TIM), cyc(CYC), Clk(CLK), vri (VRI) and pdp1 (PDP1).
Subproject 1: Circadian clock of Drosophila
The fruit-fly Drosophila melanogaster has been extensively used as a model organism to understand the molecular mechanism of the circadian clocks, the location of the circadian pacemaker neurons, as well as input and output pathways that reach or come from the body oscillators and are translated in rhythmic behavioral phenotypes. Drosophila clock neurons are dispersed throughout the brain –some are located in the dorsal and others in the lateral brain [...]
Subproject 2: Circadian clock in other insects
If on one hand the circadian clock of Drosophila melanogaster has been widely studied over the years, the molecular mechanisms and the neuronal organization of the clock of other insects are still largely unknown. We are interested especially in gathering information, both at the molecular and anatomical level, on the circadian clock of the honey bee Apis mellifera, given its incredible capability to orientate towards the sun in time compensated manner, but also of different ants species (belonging to the genus Camponotus, Cataglyphis, and Atta). So far we know that the molecular clock of these Hymenoptera is more similar to the mammalian one instead of to the one of fruit flies, but our knowledge of the neuronal network underlying the control of behavioral rhythms is still quite poor. [...]