Goto Shin G
Department of Biology and Geosciences, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, 558-8585, Japan.
J Comp Physiol B. 2016 Dec;186(8):969-984. doi: 10.1007/s00360-016-1018-9. Epub 2016 Jul 16.
Photoperiodism is an adaptive, seasonal timing system that enables organisms to coordinate their development and physiology to annual changes in the environment using day length (photoperiod) as a cue. This review summarizes our knowledge of the physiological mechanisms underlying photoperiodism in spider mites. In particular, the two-spotted spider mite Tetranychus urticae is focussed, which has long been used as a model species for studying photoperiodism. Photoperiodism is established by several physiological modules, such as the photoreceptor, photoperiodic time measurement system, counter system, and endocrine effector. It is now clear that retinal photoreception through the ocelli is indispensable for the function of photoperiodism, at least in T. urticae. Visual pigment, which comprised opsin protein and a vitamin A-based pigment, is involved in photoreception. The physiological basis of the photoperiodic time measurement system is still under debate, and we have controversial evidence for the hourglass-based time measurement and the oscillator-based time measurement. Less attention has been centred on the counter system in insects and mites. Mite reproduction is possibly regulated by the ecdysteroid, ponasterone A. Prior physiological knowledge has laid the foundation for the next steps essential for the elucidation of the molecular mechanisms driving photoperiodism.
光周期现象是一种适应性的季节性定时系统，它使生物体能够利用日长（光周期）作为线索，将其发育和生理过程与环境的年度变化相协调。本综述总结了我们对叶螨光周期现象背后生理机制的认识。特别关注的是二斑叶螨，它长期以来一直被用作研究光周期现象的模式物种。光周期现象由几个生理模块建立，如光感受器、光周期时间测量系统、计数器系统和内分泌效应器。现在很清楚，至少在二斑叶螨中，通过单眼进行视网膜光感受对于光周期现象的功能是不可或缺的。由视蛋白和基于维生素A的色素组成的视觉色素参与光感受。光周期时间测量系统的生理基础仍在争论中，并且我们对于基于沙漏的时间测量和基于振荡器的时间测量存在有争议的证据。在昆虫和螨类中，计数器系统较少受到关注。螨类的繁殖可能受蜕皮甾体、蜕皮甾酮A调节。先前的生理学知识为阐明驱动光周期现象的分子机制所需的后续步骤奠定了基础。
