Circadian clock properties of fruit flies Drosophila melanogaster exhibiting early and late emergence chronotypes

ABSTRACT

The role of circadian clocks in timing daily behaviors is widely acknowledged, and while empirical evidence suggests that clock period is correlated with the preferred phase of a rhythmic behavior (chronotype), other clock properties have also been hypothesized to underlie chronotype variation. Here, we report that fruit fly Drosophila melanogaster populations exhibiting evening emergence chronotype (late) are characterized by higher incidence of behavioral arrhythmicity in constant dim light, wider range of entrainment, reduced rates of re-entrainment to simulated jet-lag and higher amplitude of both entrained and free-running rhythms as compared to those exhibiting morning emergence chronotype (early). Our results thus highlight the role of circadian clock properties such as zeitgeber sensitivity, amplitude and coupling in driving chronotype variation.

KEYWORDS:

• Amplitude
• chronotype
• circadian
• coupling
• emergence
• evolution
• oscillator

Supplementary material available online

Supplementary Figures S1–S4, Table S1.

Declaration of interest

The authors declare no conflict of interest.

Acknowledgements

The authors thank N. Kannan, N. Mukherjee and A. Lakshman for their assistance with the experiments. We also thank Dr. Sheeba Vasu, and two anonymous reviewers for reading our manuscript and suggesting useful modifications. NKL, KV and VKS conceived the idea and designed experiments. NKL, KV and RK performed the experiments. NKL analyzed data, and NKL, KV, RK and VKS wrote the manuscript.