{"title":"Evidence of ancestral nocturnality, locomotor clock regression, and cave zone-adjusted sleep duration modes in a cave beetle","authors":"Sonya Royzenblat, Jasmina Kulacic, M. Friedrich","doi":"10.3897/subtbiol.45.100717","DOIUrl":null,"url":null,"abstract":"The small carrion beetle Ptomaphagus hirtus is an abundant inhabitant of the exceptionally biodiverse Mammoth Cave system. Previous studies revealed negative phototaxis and the expression of biological clock genes in this microphthalmic cave beetle. Here we present results from probing P. hirtus for the entrainment of locomotor rhythms using the TriKinetics activity monitor setup. Although curtailed by low adjustment frequency of animals to the test environment, the data obtained from successfully monitoring two animals in constant darkness (DD) and six animals exposed to 12 hour light-dark cycles (LD) revealed a strong effect of light on locomotor activity in P. hirtus. In LD, activity was prevalent during the artificial night phases while close to absent during the presumptive day phases, suggesting conserved nocturnality. Upon transitioning LD animals to constant darkness, none displayed detectable evidence of free-running activity rhythms, suggesting complete regression of the central circadian clock. Equally notable, overall locomotor activity of the two DD-monitored animals was about three-fold lower compared to LD animals due to longer rest durations in the former. We, therefore, propose the existence of cave zone-specific energy expenditure modes that are mediated through light schedule responsive modification of sleep duration in P. hirtus.","PeriodicalId":48493,"journal":{"name":"Subterranean Biology","volume":" ","pages":""},"PeriodicalIF":1.5000,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Subterranean Biology","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.3897/subtbiol.45.100717","RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ZOOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
The small carrion beetle Ptomaphagus hirtus is an abundant inhabitant of the exceptionally biodiverse Mammoth Cave system. Previous studies revealed negative phototaxis and the expression of biological clock genes in this microphthalmic cave beetle. Here we present results from probing P. hirtus for the entrainment of locomotor rhythms using the TriKinetics activity monitor setup. Although curtailed by low adjustment frequency of animals to the test environment, the data obtained from successfully monitoring two animals in constant darkness (DD) and six animals exposed to 12 hour light-dark cycles (LD) revealed a strong effect of light on locomotor activity in P. hirtus. In LD, activity was prevalent during the artificial night phases while close to absent during the presumptive day phases, suggesting conserved nocturnality. Upon transitioning LD animals to constant darkness, none displayed detectable evidence of free-running activity rhythms, suggesting complete regression of the central circadian clock. Equally notable, overall locomotor activity of the two DD-monitored animals was about three-fold lower compared to LD animals due to longer rest durations in the former. We, therefore, propose the existence of cave zone-specific energy expenditure modes that are mediated through light schedule responsive modification of sleep duration in P. hirtus.
期刊介绍:
Subterranean Biology is an international journal published by Pensoft on behalf of the International Society for Subterranean Biology [SIBIOS-ISSB] for the publication of original and significant contributions on all aspects of subterranean life. The Journal will consider original scientific papers dealing with any aspect of subterranean ecosystems and their components focusing on biology, ecology, evolution and conservation. Reviews and Commentaries: The journal welcomes review articles on aspects of subterranean biology. They should be submitted in the same way as research articles but use a simple layout with no more than three levels of headings. Commentaries on previous matter published in the journal may be also considered. Both reviews and commentaries will be reviewed. Book Reviews: Reviews of books, symposia volumes and conferences pertinent to the journal are welcome. The journal publishes electronic versions of the articles when these are ready to publish, without delays that might be caused by completion of an issue. These electronic versions are not "pre-prints" but final and immutable (Version of Record), hence available for the purposes of biological nomenclature. The date indicated on the electronic version is to be considered the actual publication date.