A phase response curve for circannual rhythm in the varied carpet beetle Anthrenus verbasci.
We know that entrainment, a stable phase relationship with an environmental cycle, must be established for a biological clock to function properly. Phase response curves (PRCs), which are plots of phase shifts that result as a function of the phase of a stimulus, have been created to examine the mode of entrainment. In circadian rhythms, single-light pulse PRCs have been obtained by giving a light pulse to various phases of a free-running rhythm under continuous darkness. This successfully explains the entrainment to light-dark cycles. Some organisms show circannual rhythms. In some of these, changes in photoperiod entrain the circannual rhythms. However, no single-pulse PRCs have been created. Here we show the PRC to a long-day pulse superimposed for 4 weeks over constant short days in the circannual pupation rhythm in the varied carpet beetle Anthrenus verbasci. Because the shape of that PRC closely resembles that of the Type 0 PRC with large phase shifts in circadian rhythms, we suggest that an oscillator having a common feature in the phase response with the circadian clock, produces a circannual rhythm.
Miyazaki
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Y
Department of Bio- and Geosciences, Graduate School of Science, Osaka City University, Japan. numata@sci.osaka-cu.ac.jp
Nisimura
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T
Numata
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H
D000818:Animals; D001517:Coleoptera / Q000254:growth & development / Q000502:physiology*; D003624:Darkness; D007814:Larva / Q000254:growth & development; D008027:Light; D008675:Metamorphosis, Biological / Q000502:physiology; D010507:Periodicity; D010775:Photic Stimulation; D011679:Pupa / Q000254:growth & development; D012621:Seasons