AUTHOR=Shiga Sakiko 

TITLE=Photoperiodic plasticity in circadian clock neurons in insects

JOURNAL=Frontiers in Physiology

VOLUME=4

YEAR=2013

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2013.00069

DOI=10.3389/fphys.2013.00069

ISSN=1664-042X

ABSTRACT=<p>Since Bünning's observation of circadian rhythms and photoperiodism in the runner bean <italic>Phaseolus multiflorus</italic> in 1936, many studies have shown that photoperiodism is based on the circadian clock system. In insects, involvement of circadian clock genes or neurons has been recently shown in the photoperiodic control of developmental arrests, diapause. Photoperiod sets peaks of <italic>period</italic> (<italic>per</italic>) or <italic>timeless</italic> (<italic>tim</italic>) mRNA abundance at lights-off in <italic>Sarcophaga crassipalpis</italic>, <italic>Chymomyza costata</italic> and <italic>Protophormia terraenovae</italic>. Abundance of <italic>per</italic> and <italic>Clock</italic> mRNA changes by photoperiod in <italic>Pyrrhocoris apterus</italic>. Subcellular Per distribution in circadian clock neurons changes with photoperiod in <italic>P. terraenovae</italic>. Although photoperiodism is not known in <italic>Leucophaea maderae</italic>, under longer day length, more stomata and longer commissural fibers of circadian clock neurons have been found. These plastic changes in the circadian clock neurons could be an important constituent for photoperiodic clock mechanisms to integrate repetitive photoperiodic information and produce different outputs based on day length.</p>