The Circadian Clock Improves Fitness in the Fruit Fly, Drosophila melanogaster

Abstract

It is assumed that a properly timed circadian clock enhances fitness, but only few studies have truly demonstrated this in animals. We raised each of the three classical Drosophila period mutants for >50 generations in the laboratory in competition with wildtype flies. The populations were either kept under a conventional 24-h day or under cycles that matched the mutant’s natural cycle, i.e., a 19-h day in the case of pers mutants and a 29-h day for perl mutants. The arrhythmic per0 mutants were grown together with wildtype flies under constant light that renders wildtype flies similar arrhythmic as the mutants. In addition, the mutants had to compete with wildtype flies for two summers in two consecutive years under outdoor conditions. We found that wildtype flies quickly outcompeted the mutant flies under the 24-h laboratory day and under outdoor conditions, but perl mutants persisted and even outnumbered the wildtype flies under the 29-h day in the laboratory. In contrast, pers and per0 mutants did not win against wildtype flies under the 19-h day and constant light, respectively. Our results demonstrate that wildtype flies have a clear fitness advantage in terms of fertility and offspring survival over the period mutants and – as revealed for perl mutants – this advantage appears maximal when the endogenous period resonates with the period of the environment. However, the experiments indicate that perl and pers persist at low frequencies in the population even under the 24-h day. This may be a consequence of a certain mating preference of wildtype and heterozygous females for mutant males and time differences in activity patterns between wildtype and mutants.

Loss of function in the Drosophila clock gene period results in altered intermediary lipid metabolism and increased susceptibility to starvation

“…We initiated the analysis with these non-isogenic flies. To account for genetic background effects, and since chronometabolomic studies are prone to low reproducibility due to physiological and technical variability [ 17 ], we additionally used highly isogenic WT CS and per 01 flies that were mutually backcrossed for 37 ( per 01 ) and 54 (WT CS ) generations [ 21 ] for control experiments regarding metabolites that significantly differed between the non-isogenic genotypes. In the following, the n on-isogenic and i sogenic flies are referred to as n per 01 / n WT CS and i per 01 / i WT CS , respectively.…”

The Cell Division Cycle of Euglena gracilis Indicates That the Level of Circadian Plasticity to the External Light Regime Changes in Prolonged-Stationary Cultures

“…Working with Arabidopsis thaliana , Kim et al [ 16 ] revealed that, within an individual plant, early-emerging (older) leaves had shorter circadian periods of core clock oscillator genes than late-emerging (younger) leaves. Other studies showed that—in cyanobacteria, land plants, and insects—organisms gain a fitness advantage when the external light/dark cycle (T-cycle) matches the endogenous period—a phenomenon known as “circadian resonance” [ 17 , 18 , 19 ].…”

Less is more: Light sampling via throttled visual phototransduction robustly synchronizes theDrosophilacircadian clock in the absence of Cryptochrome

“…Desynchronization between external and internal time reduces overall fitness and is linked to several physiological and mental disorders in humans [2][3][4]. It is therefore important to understand the mechanisms underlying clock synchronization with the natural environmental rhythms.…”