@inbook{295f9f641a5f46129fc52ab10a82f67b,
title = "The circadian system in insects: Cellular, molecular, and functional organization",
abstract = "The circadian clock organizes the physiology and behaviour of insects to adapt to a daily and seasonally changing environment. The clock oscillates with a period of approximately 24 h in a self-sustained manner, showing an exact 24 h period through synchronization to the daily environmental cycle, and regulates various physiological functions through neural or humoral pathways. These properties of the clock have been extensively studied at molecular and cellular levels in Drosophila melanogaster since the mid-1980s. During the last 2 decades, progress in molecular biology techniques has promoted studies on the clock system in other insects, including higher and lower phylogenetic groups, such as butterflies, honeybees, crickets, and firebrats, enabling us to compare the system, at least in part, among different insect groups.",
keywords = "Circadian rhythm, Clock gene, Clock neuron, Entrainment, Molecular oscillatory mechanism, Multicellular organization, Photoreceptor",
author = "Kenji Tomioka and Akira Matsumoto",
note = "Funding Information: During both the southward and the northward migration, the monarch butterflies utilize the time-compensated sun compass supported by the circadian clock ( ). An important information for the orientation is daylight cue, which is perceived by the compound eyes. The main retina senses the azimuthal position of the sun as the dominant source of directional information ( Guerra and Reppert, 2015 ; Reppert et al., 2016 ) ( Fig. 5 Mouritsen and Frost, 2002 ), while the polarization pattern of UVs is also sensed by UV-photoreceptors in the dorsal rim area of the compound eyes ( Labhart et al., 2009 ; Reppert et al., 2004 ). Because the sun's position in the sky continuously changes throughout a day, the flight direction of the butterfly must be adjusted according to the skylight cues, the sun's position, and the polarization pattern, depending on the time of day. Interestingly, circadian clocks in the antennae are important to yield the light-entrained time information ( Merlin et al., 2009 ; Sauman et al., 2005 ; Shlizerman et al., 2016 ). The clock neurons are also identified in the pars lateralis by immunohistochemistry, but their effect on the sun compass orientation is thought to be rather minor ( Reppert et al., 2016 ). The time information from antennal clocks is connected to the main sun compass cells existing in the central complex (CC) of the brain ( Homberg, 2015 ). These cells integrate timing information from bilateral antennae ( Guerra et al., 2012 ) with shifting skylight cues from compound eyes ( Heinze and Reppert, 2011, 2012 ; Heinze et al., 2013 ). It is thus likely that the output signal from CC is transmitted to the motor system to control flight in the right direction. Publisher Copyright: {\textcopyright} 2019 Elsevier Ltd",
year = "2019",
doi = "10.1016/bs.aiip.2019.01.001",
language = "English",
isbn = "9780081028421",
series = "Advances in Insect Physiology",
publisher = "Academic Press Inc.",
pages = "73--115",
editor = "Russell Jurenka",
booktitle = "Advances in Insect Physiology",
address = "United States",
}