| Title: | Plausible link between circa'bi'dian activity rhythms and circadian clock systems in the large black chafer Holotrichia parallela |
| Author(s): | Kawasaki Y; Nishimura H; Shiga S; |
| Address: | "Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Sumiyoshi, Osaka 558-8585, Japan. Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Sumiyoshi, Osaka 558-8585, Japan shigask@bio.sci.osaka-u.ac.jp. Department of Biological Science, Graduate School of Science, Osaka University, Machikaneyama, Toyonaka 560-0043, Japan" |
| ISSN/ISBN: | 1477-9145 (Electronic) 0022-0949 (Linking) |
| Abstract: | "Two-day rhythms, referred to as circa'bi'dian rhythms, have been reported in humans and mosquitos. However, these rhythms only appear under constant conditions, and the functional mechanisms of 2-day rhythms were unknown. Here, we report clear circabidian rhythms of large black chafers (Holotrichia parallela, Coleoptera: Scarabaeidae) in both the laboratory and field. Under 12 h:12 h light:dark (L:D) conditions at 25 degrees C, H. parallela appeared on the ground at the beginning of the dark phase every 2 days. Under constant darkness, H. parallela exhibited free-running with a period of 47.9+/-0.3 h, suggesting the existence of a clear circabidian rhythm entrained to two 12 h:12 h L:D cycles. Phase responses of the circabidian rhythm to light pulses occurred under constant darkness in a phase-dependent manner. Phase responses suggest that there are two circadian cycles, each consisting of a less-responsive and more-responsive period, in a circabidian oscillation, and the circabidian rhythm is driven by the circadian clock. A mark-recapture study showed that beetles repeatedly appeared on the same tree approximately every 2 days. However, the periodicity was not as rigid as that observed under laboratory conditions in that individuals often switched appearance days. For instance, a large precipitation made the 2-day rhythm shift phase by half a cycle of the rhythm at a time. We propose a novel function of the circadian clock characterized by the release of an output signal every two cycles to produce the 2-day rhythm" |
| Keywords: | Animals *Circadian Clocks *Circadian Rhythm Coleoptera/*physiology Darkness Female Male Beetle Mark-recapture Phase-response curve Pheromone trap Two-day rhythm; |
| Notes: | "MedlineKawasaki, Yuta Nishimura, Hitoshi Shiga, Sakiko eng Research Support, Non-U.S. Gov't England 2017/09/08 J Exp Biol. 2017 Nov 1; 220(Pt 21):4024-4034. doi: 10.1242/jeb.163253. Epub 2017 Sep 6" |
