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Cited by 121Circadian rhythm and melatoninPhysiological and biochemical adaptationsMarine Invertebrate Physiology and Ecology

An Overview of Monthly Rhythms and Clocks

Open access
Raible, Florian, Takekata, Hiroki, Tessmar-Raible, Kristin·2017·Frontiers in Neurology
DOI 10.3389/fneur.2017.00189PMC PMC5428424
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Abstract

Organisms have evolved to cope with geophysical cycles of different period lengths. In this review, we focus on the adaptations of animals to the lunar cycle, specifically, on the occurrence of biological rhythms with monthly (circalunar) or semi-monthly (circasemilunar) period lengths. Systematic experimental investigation, starting in the early twentieth century, has allowed scientists to distinguish between mythological belief and scientific facts concerning the influence of the lunar cycle on animals. These studies revealed that marine animals of various taxa exhibit circalunar or circasemilunar reproductive rhythms. Some of these rely on endogenous oscillators (circalunar or circasemilunar clocks), whereas others are directly driven by external cues, such as the changes in nocturnal illuminance. We review current insight in the molecular and cellular mechanisms involved in circalunar rhythms, focusing on recent work in corals, annelid worms, midges, and fishes. In several of these model systems, the transcript levels of some core circadian clock genes are affected by both light and endogenous circalunar oscillations. How these and other molecular changes relate to the changes in physiology or behavior over the lunar cycle remains to be determined. We further review the possible relevance of circalunar rhythms for terrestrial species, with a particular focus on mammalian reproduction. Studies on circalunar rhythms of conception or birth rates extend to humans, where the lunar cycle was suggested to also affect sleep and mental health. While these reports remain controversial, factors like the increase in "light pollution" by artificial light might contribute to discrepancies between studies. We finally discuss the existence of circalunar oscillations in mammalian physiology. We speculate that these oscillations could be the remnant of ancient circalunar oscillators that were secondarily uncoupled from a natural entrainment mechanism, but still maintained relevance for structuring the timing of reproduction or physiology. The analysis and comparison of circalunar rhythms and clocks are currently challenging due to the heterogeneity of samples concerning species diversity, environmental conditions, and chronobiological conditions. We suggest that future research will benefit from the development of standardized experimental paradigms, and common principles for recording and reporting environmental conditions, especially light spectra and intensities.

AI snapshot

Written from the paper’s full text.

TL;DR

This review synthesizes evidence for circalunar (~29.5-day) and circasemilunar (~14.75-day) rhythms and clocks across animals, especially marine reproductive cycles, and discusses molecular links to circadian clock genes. It also evaluates controversial lunar effects on terrestrial mammals and humans, emphasizing methodological heterogeneity and light pollution as challenges.

Key findings

  • Circalunar/circasemilunar rhythms are widespread in marine animals, including corals, the annelid *Platynereis dumerilii*, the midge *Clunio marinus*, sea urchins, and fishes; some are directly driven by nocturnal light, while others persist under constant conditions and are therefore clock-controlled.
  • Circadian clock gene transcripts are affected by both nocturnal light and endogenous circalunar clocks: in *Platynereis*, *pdp1*, *period*, and *clock* are elevated at full moon even without nocturnal light; in *Siganus guttatus*, *SgCry3* and *per4* show monthly periodicity without nocturnal light; coral genes *Ami-cycle*, *Ami-clock*, and *Ami-tim* also show free-running regulation.
  • Transcriptomic studies in corals found that 2% (midnight) to 6% (noon) of *Acropora millepora* genes fluctuate between new and full moon, while *Acropora gemmifera* showed 55 isogroups with diurnal expression fluctuating over the lunar cycle and 273 isogroups differentially expressed over the lunar cycle, about 0.6% of detected transcripts.
  • Terrestrial and human evidence is mixed: wildebeest conceptions fall in an April–May window determined by two consecutive full moons; badger mating behaviors peak around new moon; cattle deliveries peak shortly before full moon and are delayed up to 2 days around new moon, less than 1% of gestation length (average 284 days); human birth studies report both 2–3% elevations around full moon and non-significant results, and sleep studies report effects ranging from ~5 min shortening in children to −30% deep sleep and −20 min total sleep in one 33-subject study, with later reanalyses of >2,000 individuals finding no significant net effect.

Methods

  • Review article; no new primary data collection or experiments are reported.
  • It synthesizes historical and recent literature across taxa, including molecular studies using qPCR, quantitative RNAseq, QTL mapping/genome sequencing, and behavioral/ecological studies.
  • Main analysis is a comparative narrative synthesis of circalunar/circasemilunar rhythms, clock mechanisms, candidate photoreceptors, and terrestrial/human relevance.

Limitations

  • Authors state that analysis and comparison are challenging due to heterogeneity of samples concerning species diversity, environmental conditions, and chronobiological conditions, and they call for standardized experimental paradigms and common reporting of environmental conditions, especially light spectra and intensities.
  • Authors state that most molecular results remain correlative; functional moonlight reception has not been demonstrated for corals or reef fish, and it is unclear whether transcript changes translate into functional protein or physiology.
  • Authors state that human/terrestrial studies are controversial, with light pollution, artificial delivery methods, and possible publication bias obscuring small lunar effects; evident from the text, this is a narrative review without stated systematic search or quantitative meta-analysis.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.3389/fneur.2017.00189

Cites

91 of 91 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 106 cited sources checked · 0 supported · 0 flagged

  • Findingnone given

    In several model systems, transcript levels of some core circadian clock genes are affected by both light and endogenous circalunar oscillations.

    “In several of these model systems, the transcript levels of some core circadian clock genes are affected by both light and endogenous circalunar oscillations.”
    Quote in the paperSubstantial claim
  • Premisecitation

    The lunar cycle affects the behavior of marine animals.

    “Besides its impact on reproductive cycles, the lunar cycle also affects the behavior of marine animals.”
    Quote in the paperNot a substantial claim
  • Premisecitation

    During the Arctic winter, massive waves of diel vertical migration of zooplankton are linked to the lunar cycle, reflecting moonlight as the predominant light stimulus in that period.

    “For instance, during the Arctic winter, massive waves of diel vertical migration of the zooplankton are linked to the lunar cycle, reflecting the importance of moonlight as the predominant light stimulus in that period (17).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [17] Last, 2016, Moonlight drives ocean-scale mass vertical migration of zooplankton during the arctic winter, Curr Biol source

      Not checked in the free run.

  • Premisenone given

    Marine animals of various taxa exhibit circalunar or circasemilunar reproductive rhythms.

    “These studies revealed that marine animals of various taxa exhibit circalunar or circasemilunar reproductive rhythms.”
    Quote in the paperSubstantial claim
  • Premisecitation

    Circalunar and circasemilunar rhythms are widespread among organisms, especially in reproductive cycles of marine animals.

    “Circalunar and circasemilunar rhythms are widespread among organisms, especially in the context of reproductive cycles of marine animals.”
    Quote in the paperNot a substantial claim
  • May combine two claims. 35
  • Classified as probably not a substantial claim. 22

  • May combine two claims.

    Findingown data

    Recommended levels for room lights, as well as the illuminance from traffic or mobile phones, far exceed the illuminance even of a bright full moon.

    “A comparison of illuminance levels shows that recommended levels for room lights, as well as the illuminance from traffic or mobile phones, far exceed the illuminance even of a bright full moon (Figure 2).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Circalunar or circasemilunar reproductive rhythms also exist in species of other eukaryotic kingdoms, such as the brown alga Dictyota dichotoma and the Peruvian apple cactus Cereus peruvianus.

    “While our review focuses on the animal kingdom, it should be noted that circalunar or circasemilunar reproductive rhythms also exist in species of other eukaryotic kingdoms, such as the brown alga Dictyota dichotoma (kingdom Chromalveolata) (18) or the Peruvian apple cactus Cereus peruvianus (kingdom Archaeplastida) (19, 20).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [18] Bünning, 1961, Wie messen Organismen lunare Zyklen?, Z Naturforsch source

      Not checked in the free run.

    • cites [19] Ben-Attia, 2016, Blooming rhythms of cactus Cereus peruvianus with nocturnal peak at full moon during seasons of prolonged daytime photoperiod, Chronobiol Int source

      Not checked in the free run.

    • cites [20] Reinberg, 2016, The full moon as a synchronizer of circa-monthly biological rhythms: chronobiologic perspectives based on multidisciplinary naturalistic research, Chronobiol Int source

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    Some circalunar or circasemilunar reproductive rhythms rely on endogenous oscillators (circalunar or circasemilunar clocks), whereas others are directly driven by external cues such as changes in nocturnal illuminance.

    “Some of these rely on endogenous oscillators (circalunar or circasemilunar clocks), whereas others are directly driven by external cues, such as the changes in nocturnal illuminance.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    In A. millepora, both cry1 and cry2 are induced by sunlight, with no reproducible transcript changes without light.

    “the first study by Levy et al. showed that both cry1 and cry2 are induced by sunlight (with no reproducible transcript changes without light).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [24] Levy, 2007, Light-responsive cryptochromes from a simple multicellular animal, the coral Acropora millepora, Science source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In Acropora millepora, three types of Crys were identified: Ami-Cry1 has closest homology to tr-Crys, Ami-Cry2 is in the 6-4 photolyase group, and Ami-CryDash is related to the Cry-DASH group.

    “In the coral Acropora millepora, three types of Crys were identified (24): Ami-Cry1 has closest homology to tr-Crys, Ami-Cry2 is positioned in the group of the 6-4 photolyases, while the third molecule, Ami-CryDash, is related to another ancient group of Crys that has been dubbed “cry-Drosophila, Arabidopsis, Synechocystis, Homo” (Cry-DASH) due to its broad evolutionary conservation (32).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [24] Levy, 2007, Light-responsive cryptochromes from a simple multicellular animal, the coral Acropora millepora, Science source

      Not checked in the free run.

    • cites [32] Chaves, 2011, The cryptochromes: blue light photoreceptors in plants and animals, Annu Rev Plant Biol source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In A. millepora, cry1 levels fluctuated, with elevated expression at midnight during the first-quarter moon.

    “Furthermore, in their study, also cry1 levels showed fluctuations, with elevated expression levels at midnight during the first-quarter moon (23).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [23] Brady, 2016, Lunar phase modulates circadian gene expression cycles in the broadcast spawning coral Acropora millepora, Biol Bull source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Circalunar timing mechanisms rarely exist in isolation but are coordinated with other timing mechanisms such as daily (circadian) timing.

    “As mentioned earlier, circalunar timing mechanisms rarely exist in isolation, but are coordinated with other timing mechanisms, such as daily (circadian) timing.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    Plant-type Cryptochromes exist in animals and diatoms.

    “Members of a family called “plant-type Cryptochromes” also exist in animals and diatoms.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    In A. millepora sampled during natural full moon nights, cry2 transcript levels were significantly higher than during new moon nights, while cry1 levels did not differ.

    “In addition, when animals were sampled during natural full moon nights, cry2 transcript levels were significantly higher than during new moon nights (24), while cry1 levels did not show a difference.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [24] Levy, 2007, Light-responsive cryptochromes from a simple multicellular animal, the coral Acropora millepora, Science source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Members of the v-Cry/Cry2/tr-Cry family function as transcriptional repressors in the circadian transcription/translational core loop.

    “whereas members of the distinct v-Cry/Cry2/tr-Cry family function as transcriptional repressors in the circadian transcription/translational core loop [reviewed in Ref. (37)].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [37] Takahashi, 2015, Molecular components of the circadian clock in mammals, Diabetes Obes Metab source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    In plants, plant-type Cryptochromes function as photoreceptors for the plant circadian clock.

    “In plants, members of this family have been shown to function as photoreceptors for the plant circadian clock [reviewed in Ref. (38)].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [38] Möglich, 2010, Structure and function of plant photoreceptors, Annu Rev Plant source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Cryptochromes are flavoproteins involved in cellular signaling, anciently related to photolyases, UV-responsive DNA repair enzymes.

    “Crys are flavoproteins involved in cellular signaling, which are anciently related to photolyases, UV-responsive DNA repair enzymes (32).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [32] Chaves, 2011, The cryptochromes: blue light photoreceptors in plants and animals, Annu Rev Plant Biol source

      Not checked in the free run.

  • May combine two claims.

    Study design and conductcitation

    In omission experiments, a circalunar rhythm produced by direct impact will not persist, whereas a clock-mediated circalunar rhythm will persist.

    “Whereas a circalunar rhythm produced by direct impact will not persist under such conditions, a clock-mediated circalunar rhythm will be able to persist.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [21] Enright, 1981, Methodology source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Under nocturnal light conditions sufficient to reset the circalunar clock of Platynereis, oscillations of tr-cry are abolished, indicating that nocturnal light stimuli can affect circadian clock gene expression.

    “Under nocturnal light conditions that are sufficient to reset the circalunar clock of these animals, the oscillations of tr-cry are abolished, indicating that nocturnal light stimuli can affect circadian clock gene expression.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [22] Zantke, 2013, Circadian and circalunar clock interactions in a marine annelid, Cell Rep source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    In A. millepora, midnight cry1 and cry2 transcript levels still showed differences at different phases of the lunar cycle independent of illumination, consistent with corals possessing a circalunar clock.

    “Interestingly, midnight cry1 and cry2 transcript levels still showed differences at different phases of the lunar cycle independent of illumination, consistent with the idea that corals also possess a circalunar clock.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [23] Brady, 2016, Lunar phase modulates circadian gene expression cycles in the broadcast spawning coral Acropora millepora, Biol Bull source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In Favia fragum, cry1 and cry2 orthologs exhibit light-controlled daily oscillations and transcript level differences between different moon phases.

    “Both genes exhibit light-controlled daily oscillations and also transcript level differences between different moon phases (27).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [27] Hoadley, 2011, Circadian clock gene expression in the coral Favia fragum over diel and lunar reproductive cycles, PLoS One source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    In S. guttatus, SgCry1 levels are controlled by light, whereas SgCry3 levels continue to exhibit monthly periodicity even in the absence of nocturnal light cues, providing strong evidence that SgCry3 is under the control of an endogenous monthly clock.

    “Whereas SgCry1 levels are controlled by light, SgCry3 levels continue to exhibit a monthly periodicity even in the absence of nocturnal light cues, providing strong evidence that this gene is under the control of an endogenous monthly clock (31).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [31] Toda, 2014, Hypothalamic expression and moonlight-independent changes of Cry3 and Per4 implicate their roles in lunar clock oscillators of the lunar-responsive goldlined spinefoot, PLoS One source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Platynereis tr-Cry functions as a transcriptional repressor, but not a light receptor, when tested in S2 tissue culture cells.

    “When tested in S2 tissue culture cells, Platynereis tr-Cry functions as a transcriptional repressor, but not a light receptor, consistent with a conserved function of this molecule in transcriptional circadian control.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [22] Zantke, 2013, Circadian and circalunar clock interactions in a marine annelid, Cell Rep source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    Both natural and experimental changes in nocturnal illumination, as well as endogenously running circalunar clocks, impact transcript levels of circadian clock gene homologs in marine organisms as diverse as corals, annelid worm, and fish.

    “Taken together, it appears that both natural and experimental changes in nocturnal illumination, as well as endogenously running circalunar clocks impact on the transcript levels of circadian clock gene homologs in marine organisms as diverse as corals, annelid worm, and fish.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Platynereis L-cry functions as a light receptor when tested in S2 cells and shows fluctuations in transcript levels between day and night.

    “Also, Platynereis L-cry, which functions as a light receptor when tested in S2 cells, shows fluctuations in transcript levels between day and night.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [22] Zantke, 2013, Circadian and circalunar clock interactions in a marine annelid, Cell Rep source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Both nocturnal light and the circalunar clock appear to impact expression of Platynereis L-cry.

    “Both nocturnal light and the circalunar clock appear to impact on the expression of this gene.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [22] Zantke, 2013, Circadian and circalunar clock interactions in a marine annelid, Cell Rep source

      Not checked in the free run.

    • cites [28] Tessmar-Raible, 2014, Circadian and circalunar clock interactions and the impact of light in Platynereis dumerilii

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Melatonin-proficient mice appear to possess a similar ability to induce eya3, suggesting that this mechanism could be evolutionarily conserved.

    “Melatonin-proficient mice appear to possess a similar ability to induce eya3, suggesting that this mechanism could be evolutionarily conserved (57).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [57] Masumoto, 2010, Acute induction of Eya3 by late-night light stimulation triggers TSHbeta; expression in photoperiodism, Curr Biol source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premiseown data

    For moonlight, the difference in light intensity from sunlight is around five to six orders of magnitude.

    “For moonlight, this difference in light intensity is even around five to six orders of magnitude (see Figure 2).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Figure 2

      Not checked in the free run.

  • May combine two claims.

    Premisereasoning

    A functional requirement for moon light reception has neither been demonstrated for the reef fish nor for any of the corals.

    “A functional requirement for moon light reception has neither been demonstrated for the reef fish nor for any of the corals.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Current analysis in C. marinus is consistent with the idea that circadian and circalunar timing mechanisms are distinct, as none of the core circadian clock genes is involved in circalunar timing variation.

    “Interestingly, the current analysis in the midge is consistent with the idea that circadian and circalunar timing mechanisms are distinct, as none of the core circadian clock genes is involved in circalunar timing variation (29).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [29] Kaiser, 2016, The genomic basis of circadian and circalunar timing adaptations in a midge, Nature source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Previous analyses suggest that nocturnal light of different wavelengths is suitable as an entraining stimulus for the worm's circalunar clock.

    “Interestingly, previous analyses on the properties of the light suitable for the entrainment of the worm’s circalunar clock suggests that nocturnal light of different wavelengths is suitable as entraining stimulus (11).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [11] Hauenschild, 1960, Lunar periodicity, Cold Spring Harb Symp Quant Biol source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In the sheep pars tuberalis, transcript levels of Eya3 are controlled both by a circadian signal (that licenses eya3 transcription 12 h after night fall) and by acute levels of melatonin (that lead to suppression of eya3 transcription during darkness).

    “In the sheep pars tuberalis, transcript levels of the transcription factor Eyes absent 3 (Eya3) are controlled both by a circadian signal (that licenses eya3 transcription 12 h after night fall) and by the acute levels of melatonin (that lead to a suppression of eya3 transcription during darkness).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [56] Dardente, 2010, A molecular switch for photoperiod responsiveness in mammals, Curr Biol source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    A general trend in the reviewed studies is that both nocturnal light and free-running circalunar clocks impact the transcript level of specific genes.

    “A general trend in all of the reviewed studies is that both nocturnal light and free-running circalunar clocks impact on the transcript level of specific genes.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    The two gene sets in A. gemmifera were largely non-overlapping, resulting in an overall detected change of transcripts over the lunar cycle of about 0.6%.

    “These two gene sets were largely non-overlapping, resulting in an overall detected change of transcripts over the lunar cycle of about 0.6% [Ref. (28); Vince, personal communication concerning which EST dataset was exactly used for the mapping of the reads].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [28] Tessmar-Raible, 2014, Circadian and circalunar clock interactions and the impact of light in Platynereis dumerilii

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Photoperiodism is a widespread phenomenon, occurring in phyla ranging from rotifers and annelids to birds and mammals, helping these animals to anticipate the change of seasons and to adjust their physiology and behavior accordingly.

    “Photoperiodism is a widespread phenomenon, occurring in phyla ranging from rotifers and annelids to birds and mammals, helping these animals to anticipate the change of seasons and to adjust their physiology and behavior accordingly [reviewed in Ref. (50, 51)].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [50] Bradshaw, 2007, Evolution of animal photoperiodism, Annu Rev Ecol Evol Syst source

      Not checked in the free run.

    • cites [51] Nelson, 2010

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In A. gemmifera, one set of 55 isogroups showed diurnal expression patterns that fluctuated over the lunar cycle, whereas a second set of 273 isogroups exhibited differential expression over the lunar cycle when noon and midnight sampling timepoints were combined.

    “Two sets of regulated transcript types were identified from the quantitative RNA sequencing: one set (55 isogroups) showed diurnal expression patterns that fluctuated over the course of the lunar cycle, whereas the second set (273 isogroups) exhibited differential expression over the lunar cycle when noon and midnight sampling timepoints were combined (26).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [26] Oldach, 2017, Transcriptome dynamics over a lunar month in a broadcast spawning acroporid coral, Mol Ecol source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    Light pollution caused by industrialization/electrification is a factor that is likely to obscure natural responses to moonlight or even disturb the respective rhythms.

    “Moreover, light pollution caused by the process of industrialization/electrification is a factor that is likely to obscure natural responses to moonlight or even disturb the respective rhythms (see the more extended discussion on this topic below).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    The European badger typically mates in February to March, soon after females have given birth to the previous litter; during lactation, embryos are in a diapause state, before seasonal cues (photoperiod and temperature) lead to implantation around the end of December.

    “The animals typically mate in February to March, soon after the females have given birth to the previous litter. During lactation, the embryos are in a diapause state, before seasonal cues (photoperiod and temperature) lead to implantation around the end of December (62, 63).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [62] Canivenc, 1956, Présence de blastocystes libres intra-utérins au cours de la lactation chez le Blaireau européen (Meles meles), C r séances Soc biol ses fil

      Not checked in the free run.

    • cites [63] Canivenc, 1979, Delayed implantation is under environmental control in the badger (Meles meles L.), Nature source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Cattle have been domesticated for around 10,000 years.

    “Given that cattle have been domesticated for around 10,000 years (66), it is possible that this effect represents just a remnant of a more pronounced trait that might have been more relevant in the wild.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [66] Bollongino, 2012, Modern taurine cattle descended from small number of near-eastern founders, Mol Biol Evol source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    This switch could even be a switch between a long-day photoperiod to a short-day photoperiod, providing a direct parallel to photoperiodic responses in other animals.

    “notably, this could even be a switch between a long-day photoperiod to a short-day photoperiod, providing a direct parallel to photoperiodic responses in other animals (11).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [11] Hauenschild, 1960, Lunar periodicity, Cold Spring Harb Symp Quant Biol source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In a systematic, 3-year study on over 400 Holstein cows, Yonezawa and colleagues reported a significant influence of the moon phase on spontaneous delivery dates, with deliveries peaking shortly before the full moon, while being minimal around new moon.

    “In a systematic, 3-year study on over 400 Holstein cows raised on a Japanese farm, Yonezawa and colleagues recently reported a significant influence of the moon phase on spontaneous delivery dates, with deliveries peaking shortly before the full moon, while being minimal around new moon (65).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [65] Yonezawa, 2016, Lunar cycle influences spontaneous delivery in cows, PLoS One source

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    Mammals are characterized by internal fertilization and typically an independence of the tides.

    “in terms of reproductive strategies, mammals are characterized by internal fertilization and typically an independence of the tides.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    The two highlighted species in which copulations are limited (wildebeest and badgers) display a clear seasonality in reproduction.

    “The two highlighted species in which copulations are limited (wildebeest and badgers) display a clear seasonality in reproduction.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    The lunar cycle is not the only relevant cycle governing reproduction in wildebeest and badgers but is also integrated with information on the season.

    “The lunar cycle therefore is not the only relevant cycle governing reproduction but is also integrated with information on the season.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    One of the first studies systematically investigating the frequency of births in a large, longitudinal study (1948-1957, around 250,000 births) concluded that around the full moon, birth rates (calculated as a sliding window of 3-day averages) were between 2 and 3% elevated over the average, whereas the time point around new moon showed a reduced birth rate (2-3% below average).

    “One of the first studies systematically investigating the frequency of births in a large, longitudinal study (1948–1957, around 250,000 births) concluded that around the full moon, birth rates (calculated as a sliding window of 3-day averages) were between 2 and 3% elevated over the average, whereas the time point around new moon showed a reduced birth rate (2–3% below average).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [68] Menaker, 1959, Lunar periodicity in human reproduction: a likely unit of biological time, Am J Obstet Gynecol source

      Not checked in the free run.

  • May combine two claims.

    Premisereasoning

    The lunar cycle leads to periodic changes not only in the intensity but also the time of nocturnal light (as moon rise and moon set move with respect to the circadian cycle).

    “Like in the case of the photoperiod, the lunar cycle leads to periodic changes not only in the intensity but also the time of nocturnal light (as moon rise and moon set move with respect to the circadian cycle).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Brady et al. observed that levels of a gene with similarity to the eyes absent family changed when compared between full moon and new moon nights.

    “It is interesting, however, that in one of the aforementioned studies on coral gene expression, Brady et al. also observed that levels of a gene with similarity to the eyes absent family changed when compared between full moon and new moon nights (23).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [23] Brady, 2016, Lunar phase modulates circadian gene expression cycles in the broadcast spawning coral Acropora millepora, Biol Bull source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Reduced sleep is a common parameter in conditions causing mania in patients with bipolar disorder and can also increase the chance of epileptic seizures.

    “As reduced sleep is a common parameter in conditions causing mania in patients with bipolar disorder (75) and can also increase the chance of epileptic seizures (76, 77)”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [75] Wehr, 1987, Sleep reduction as a final common pathway in the genesis of mania, Am J Psychiatry source

      Not checked in the free run.

    • cites [76] Rajna, 1993, Correlations between night sleep duration and seizure frequency in temporal lobe epilepsy, Epilepsia source

      Not checked in the free run.

    • cites [77] Shouse, 1996, Circadian rhythm, sleep, and epilepsy, J Clin Neurophysiol source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    It is currently completely unclear if the subjects in the mentioned studies were likely to have synchronized oscillations or if these oscillations were offset between individuals.

    “it would currently be completely unclear if the subjects in either of the mentioned studies were likely to have synchronized oscillations or if these oscillations were offset between individuals.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Both of the more recent studies report a significant drop of birth rates on weekends in their respective datasets.

    “Of note, both of the more recent studies report a significant drop of birth rates on weekends in their respective datasets (70, 71).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [70] Guillon, 1988, [Seasonal, weekly and lunar cycles of birth. Statistical study of 12,035,680 births], Rev Fr Gynecol Obstet

      Not checked in the free run.

    • cites [71] Waldhoer, 2002, The lunar cycle and the number of deliveries in Austria between 1970 and 1999, Gynecol Obstet Invest source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Artificial light is changing both the spectrum and intensity of nocturnal light, with local increases in intensities of up to 20% per year.

    “and are changing both the spectrum and intensity of nocturnal light, with local increases in intensities of up to 20% per year (85).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [85] Hölker, 2010, The dark side of light: a transdisciplinary research agenda for light pollution policy, Ecol Soc source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    These nights led to a decrease in human night sleep around the full moon until around 200 years ago.

    “and that these nights therefore led to a decrease in human night sleep around the full moon until around 200 years ago.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [73] Raison, 1999, The moon and madness reconsidered, J Affect Disord source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    The children in this study were monitored remotely in their home environments, and thereby could have been exposed to moonlight in their bedrooms.

    “The children in this study were monitored remotely in their home environments, and thereby could have been exposed to moonlight in their bedrooms.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Waldhoer and colleagues on around 2.5 mio births in Austria between 1970 and 1999 did not find evidence for a significant correlation between birth rates and lunar phases.

    “Others, however, do not find evidence for a significant correlation, such as a study by Waldhoer and colleagues on around 2.5 mio births in Austria between 1970 and 1999 (71).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [71] Waldhoer, 2002, The lunar cycle and the number of deliveries in Austria between 1970 and 1999, Gynecol Obstet Invest source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    If nocturnal light played a role in adjusting an individual's circalunar clock, changes in the availability and spectrum of nocturnal light could easily impact on the phase of such a clock.

    “For instance, if nocturnal light played a role in adjusting an individual’s circalunar clock—as evident for several of the marine species discussed earlier—changes in the availability and spectrum of nocturnal light could easily impact on the phase of such a clock.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S1 (asserted).

    Premisecitation

    In the pre-industrialized world, moonlit nights-especially the three days surrounding full moon-provided a natural opportunity to perform work, hunt, or travel.

    “one line of arguments is that in the pre-industrialized world, moonlit nights—especially the three days surrounding full moon—provided a natural opportunity to perform work, hunt, or travel (73)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [73] Raison, 1999, The moon and madness reconsidered, J Affect Disord source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    The advent of artificial illumination ended the dependence of humans on moon light as an exclusive nocturnal light source, thereby causing more stable sleep-wake patterns, and dissolving any apparent lunar periodicity in mental illnesses.

    “Following this line of reasoning, the advent of artificial illumination ended the dependence of humans on moon light as an exclusive nocturnal light source, thereby causing more stable sleep–wake patterns, and dissolving any apparent lunar periodicity in mental illnesses.”
    Quote in the paperNot a substantial claim
52 of 52

  • The paper relies on this without support.

    The lunar cycle leads to periodic changes not only in intensity but also the time of nocturnal light.

    “Like in the case of the photoperiod, the lunar cycle leads to periodic changes not only in the intensity but also the time of nocturnal light (as moon rise and moon set move with respect to the circadian cycle).”

  • The paper relies on this without support.

    The actual time point of the light stimulus with respect to the 24-h cycle is highly relevant for its interpretation.

    “(ii) Even though the intensity of the relevant light stimulus is therefore very small, in both cases, the actual time point of the stimulus with respect to the 24-h cycle is highly relevant for its interpretation.”

  • The paper relies on this without support.

    Mammals are characterized by internal fertilization and typically an independence of the tides.

    “in terms of reproductive strategies, mammals are characterized by internal fertilization and typically an independence of the tides.”

  • The paper relies on this without support.

    In marine broadcast spawners and species reproducing within the tidal zone, precise synchronization of mating time between sexes is essential for maintaining reproductive success.

    “where precise synchronization of mating time between sexes is essential for maintaining reproductive success.”

  • The paper relies on this without support.

    Internally fertilizing animals can uncouple copulation from fertilization.

    “By contrast, internally fertilizing animals can uncouple copulation from fertilization.”

  • The paper relies on this without support.

    Most studies on lunar effects on human sleep result from sleep laboratories, in which external light sources like moonlight were systematically excluded.

    “Most studies on that subject, however, result from sleep laboratories, in which external light sources like moonlight were systematically excluded.”

  • The paper relies on this without support.

    The spectral composition of artificial light sources can strongly deviate from sun or moon light.

    “Moreover, the spectral composition of artificial light sources can strongly deviate from sun or moon light”
7 of 7

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Eya3 photoperiod conclusion reverses the stated mechanism

    Minor

    The stated mechanism permits eya3 transcription 12 hours after nightfall but suppresses it while it is dark. At that time, light is expected under a long photoperiod, not a short one, so the claimed direction of upregulation is reversed.

1 of 1

Cites

Flagged first, then by citations

Research works printed but not linked: 5

  1. Clark, 1925, The life history of Leuresthes tenuis, an atherine fish with tide controlled spawning habits, Fish Bull, 10, 1
  2. Nelson, 2010, Photoperiodism
  3. Posch, 2013, Das Ende der Nacht
  4. Canivenc, 1956, Présence de blastocystes libres intra-utérins au cours de la lactation chez le Blaireau européen (Meles meles), C r séances Soc biol ses fil, 150, 1193
  5. Service, 2002, Occurrence of monthly oestrous periods in badgers (Meles meles): a mechanism for observed variation in breeding patterns?, Adv Ethol, 37, 149

Cited by

Sorted by citations

Related

Authors
Raible, F., Takekata, H., & Tessmar-Raible, K.
Affiliations
University of Vienna (AT)
Corresponding author
Raible, Florian
ORCID
Venue
Frontiers in Neurology
Publisher
Frontiers Media SA
Published
2017-05-12
Volume
8
Pages
189-189
ISSN
1664-2295 (ISSN-L)
DOI
10.3389/fneur.2017.00189
PMC
PMC5428424
OpenAlex
W2612303882
Semantic Scholar
39decd80a8bbc40aabe2df2e877757aea5363dcf
Cited by
121
References
91
Citations by year
2026: 26 · 2025: 12 · 2024: 10 · 2023: 13 · 2022: 16 · 2021: 10 · 2020: 16 · 2019: 12 · 2018: 5 · 2017: 1
FWCI
1.13
Type
journal article
Language
en
Open access
Licence
cc-by
Locations
  • Frontiers in Neurology (publishedVersion, cc-by)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Phaidra (Universität Wien) (submittedVersion, cc-by-nc-nd)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion)
Funders
  • Austrian Science Fund (P30035, P28970)
  • European Research Council (337011)
  • Japan Society for the Promotion of Science (Overseas Fellow)
Topics
  • Life Sciences › Neuroscience › Endocrine and Autonomic Systems › Circadian rhythm and melatonin
  • Physical Sciences › Environmental Science › Ecology › Physiological and biochemical adaptations
  • Physical Sciences › Earth and Planetary Sciences › Paleontology › Marine Invertebrate Physiology and Ecology
Keywords
circalunar rhythm, lunar cycle, biological clock, reproductive rhythm, marine fauna, coral, annelid worms, midges, fish, clock genes, light entrainment, mammalian reproduction, sleep, mental health, light pollution, chronobiology

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-09.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-09.

Statistics and arithmetic are recomputed, not judged.

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