Circadian clock properties of fruit flies <i>Drosophila melanogaster</i> exhibiting <i>early</i> and <i>late</i> emergence chronotypes

<p>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 <i>Drosophila melanogaster</i> populations exhibiting evening emergence chronotype (<i>late</i>) 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 (<i>early</i>). Our results thus highlight the role of circadian clock properties such as zeitgeber sensitivity, amplitude and coupling in driving chronotype variation.</p>