Circannual Rhythms Anticipate the Earth’s Annual Periodicity

Helm, Barbara; Lincoln, G. A.

doi:10.1007/978-81-322-3688-7_26

Cited by 13 publications

(23 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has long been known that free‐running circannual periods in living organisms vary in length and rarely match the 365‐day year (Gwinner, ). However, it was only recently proposed that the variation in circannual periods is adaptive: polymorphism in annual chronotypes facilitates a good match between the life histories and environments of organisms (Helm & Lincoln, ; Helm & Shavit, ; Helm et al., ). Here, we, for the first time, provide correlative evidence suggesting that annual chronotypes are the outcome of endogenous‐clock properties having been adjusted to selective environments.…”

Section: Discussionmentioning

confidence: 99%

“…The opposite should hold for birds with “slow” life histories. Therefore, when survival–reproduction trade‐off is mediated by timing of breeding, resource allocation to either fitness component can be optimized by fine‐tuning the timing of spring activities, as it is often found in birds breeding in seasonal environments at temperate and northern latitudes (Drent & Daan, ; Helm & Lincoln, ; Karagicheva, Liebers, et al., ; Öberg, Pärt, Arlt, Laugen, & Low, ).…”

Section: Introductionmentioning

confidence: 99%

“…Whether exposure to environmental cues will facilitate or delay exertion of seasonal activities largely depends on the period‐length relationship between the circannual oscillator and the environmental cycle (in this case: year). According to the phase‐period rule, deviation of intrinsic periods from environmental cycles, that is, the cycles of environmental Zeitgebers, will affect the rate of entrainment (cue response) and determine whether the animal has an early or a late chronotype (Helm & Lincoln, ; Helm et al., ; Roenneberg, Daan, & Merrow, ). A number of factors can affect the rate of entrainment, but in general, organisms with relatively short intrinsic cycles will be early and the ones with long cycles will be late (Floessner & Hut, ; Roenneberg et al., ).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Annual chronotypes functionally link life histories and life cycles in birds

et al. 2018

View full text Add to dashboard Cite

Life‐history responses to ecological selection pressures can be described by a slow–fast life‐history axis. Along this axis, fast‐living animals usually invest in high breeding output, whereas slow‐living ones prioritize their own survival. Birds may solve the trade‐off between reproduction and survival by optimizing their seasonal schedules. Breeding early tends to facilitate reproductive success, whereas breeding late increases the chances to survive. On the basis of this argument, short‐ and long‐lived birds should benefit from initiating spring activities earlier and later, respectively. The timing of seasonal activities, all else being equal, depends on the architecture of endogenous circannual clocks. Particularly, the length of the circannual period relative to the 365‐day environmental year either facilitates the anticipation of seasonal activities (in case of periods shorter than 365 days) or represents a responsive mode (when periods are longer than 365 days). The two alternatives will be manifested by early or late annual chronotypes, respectively. We hypothesize that in birds, annual chronotype will correspond with position on the “pace‐of‐life scale.” Species with low survival probability, and thus a poor chance of breeding in a next season, should show early annual chronotypes facilitated by circannual‐clock periods shorter than 365 days. In contrast, species with high survival rates should benefit from relatively long circannual periods. We predicted that circannual‐period lengths should correlate positively with species‐specific adult annual survival rates. Using published data for 16 wild bird species, we confirmed the predicted correlation. In our analysis, we accounted for the possible metabolic nature of circannual clocks, a correlation between rate of metabolism and survival, and phylogenetic relationships. On the basis of our finding, we propose that evolutionary responsive circannual clocks help birds cope with temporal variation in the environment in ways that are most appropriate for their life‐history and life‐table attributes. A http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.13181/suppinfo is available for this article.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Annual chronotypes functionally link life histories and life cycles in birds

et al. 2018

View full text Add to dashboard Cite

show abstract

“…32 In the antler, transplantation of the living pedicle tissues to different parts of the body, and between animals at different phases of the annual cycle, demonstrates remarkable autonomy in tissue timing 33 ; the antler stem cells have been characterised in tissue culture. 6,15 It is also notable that the removal of sex steroid hormones by castration, and/or blockade of the photoperiodic entrainment relay by pinealectomy, does not prevent the expression of endogenous circannual rhythms. 35 Other evidence for the local control comes from the observation that circannual cycles in different physiological systems (eg, feather moult and body weight) become desynchronised under constant free-running conditions.…”

Section: Circ Ann Ual Clo Ck Work Org Anisationmentioning

confidence: 99%

“…6 It is inspirational to recognise that, within a single cell, both yearly and daily timing systems operate simultaneously (and largely independently). Circannual and circadian timing systems share formal properties: ancestry, cell autonomy, innateness, entrainment, temperature compensation and ubiquity.…”

Section: Con Clus Ionsmentioning

confidence: 99%

A brief history of circannual time

Lincoln

2019

J Neuroendocrinology

View full text Add to dashboard Cite

Innate circannual timing is an ancestral trait that first evolved in free‐living eukaryotic cells some 2000 million years ago, with marine algae of the genus Allexandrium providing a living unicellular model. This species shows the primitive trait of ‘alternation of generations’, where the organism alternates between fast replicating vegetative cells in the summer and a dormant cystic cell over the winter. The resistant cysts sink into the cold ocean sediments. Remarkably, excystment in spring is governed by an endogenous circannual timing mechanism. Thus, a tiny, short‐lived unicell can utilise a circannual clock as part of the life‐history programme of the species. Innate timing allows for major adjustments in physiology and behaviour in anticipation of the seasons, and provides an internalised sense of seasonal time for the many species where standard environmental cues are weak or ambiguous. This is a highly adaptive strategy irrespective of the size and longevity of an organism. Circannual rhythms are expressed by a diverse range of organisms, from flowering plants to mammals, interwoven into the life‐history programme of each species, being a consequence of forever living in a periodic world. In complex vertebrates, the early division of the zygote potentially carries circannual timer genes into all progeny cells and tissues. This supports the concept of a ‘clock‐shop’ where cell‐autonomous long‐term rhythms are generated in each tissue, orchestrated by a central circannual pacemaker system. This is analogous to the organisation of the circadian timing system. For the circannual time‐scale, specialised thyrotroph cells located in the pars tuberalis of the pituitary gland and adjacent tanycyte cells located in the ependymal wall of the third cerebral ventricle of the brain act as putative central circannual pacemakers. At a molecular level, epigenetically regulated, cyclical remodelling of chromatin, which determines whether specific circannual timer genes are transcriptionally active, or not, is considered to drive the oscillation between the summer and winter phenotypes.

show abstract

Annual transcriptome of a key zooplankton species, the copepod Calanus finmarchicus

Payton

Noirot

Last

et al. 2022

Ecology and Evolution

View full text Add to dashboard Cite

The copepod Calanus finmarchicus (Crustacea, Copepoda) is a key zooplanktonic species with a crucial position in the North Atlantic food web and significant contributor to ocean carbon flux. Like many other high latitude animals, it has evolved a programmed arrested development called diapause to cope with long periods of limited food supply, while growth and reproduction are timed to take advantage of seasonal peaks in primary production. However, anthropogenic warming is inducing changes in the expected timing of phytoplankton blooms, suggesting phenological mismatches with negative consequences for the N. Atlantic ecosystem. While diapause mechanisms are mainly studied in terrestrial arthropods, specifically on laboratory model species, such as the fruit fly Drosophila, the molecular investigations of annual rhythms in wild marine species remain fragmentary. Here we performed a rigorous year‐long monthly sampling campaign of C. finmarchicus in a Scottish Loch (UK; 56.45°N, 5.18°W) to generate an annual transcriptome. The mRNA of 36 samples (monthly triplicate of 25 individuals) have been deeply sequenced with an average depth of 137 ± 4 million reads (mean ± SE) per sample, aligned to the reference transcriptome, and filtered. We detail the quality assessment of the datasets and provide a high‐quality resource for the investigation of wild annual transcriptomic rhythms (35,357 components) in a key diapausing zooplanktonic species.

show abstract

Circannual Rhythms Anticipate the Earth’s Annual Periodicity

Cited by 13 publications

References 54 publications

Annual chronotypes functionally link life histories and life cycles in birds

Annual chronotypes functionally link life histories and life cycles in birds

A brief history of circannual time

Annual transcriptome of a key zooplankton species, the copepod Calanus finmarchicus

Contact Info

Product

Resources

About