Dedicated Issue ‐ Biochronometry in Insects

Abstract

This issue collects papers on biochronometry, i.e., biological time measurement, in insects including circadian and non-circadian rhythms and photoperiodism. This is dedicated to Professor Sinzo Masaki to celebrate his 90th year. He has been one of the leaders in this field and served Physiological Entomology as an editorial advisor for more than 23 years (1985–2008). David Saunders and Graham Goldsworthy kindly wrote tributes to him for this issue. Time measurement has been under the spotlight in insect physiology. Major concepts in chronobiology were proposed on experimental results in insect circadian rhythms: Gate for population rhythms, temperature compensation of the period, etc. In photoperiodism, major theoretical models for measuring the day- or night-length were developed also on experimental results in insects. Moreover, biological rhythms with periods far from a day, i.e., circannual, circatidal, circa(semi)lunar rhythms, were also discovered in insects. Although most of these results were reported in the second half of the 20th century, this scientific field is still evolving with development of technology, such as cell-specific gene expression, RNAi, next generation DNA sequencing, and genome editing. This issue collects three reviews and seven original papers. The reviews deal with circadian factors in adaptation to natural or man-made environment. The original papers report recent progress in biochronometry, including sleep regulation, resetting of a circadian and a circannual clock, circadian control of metabolism, diapause induction mechanisms, and a novel approach to a photoperiodic time-measurement mechanism. Although these papers cover only a small fraction of the fields related to biochronometry in insects, we hope this issue will help to introduce readers to several new aspects of insect biochronometry and provide motivation for further research on this fascinating topic.