Photoperiodic changes influence the incorporation of vitellin yolk protein by oocytes of the semelparous polychaete Nereis (Neanthes) Virens

Nereidae are vital to the functioning of estuarine ecosystems and are major components in the diets of over-wintering birds and commercial fish. They use environmental cues to synchronize reproduction. Photoperiod is the proximate cue, initiating vitellogenesis in a temperature-compensated process. The prevailing paradigm in Nereidae is of a single ‘juvenile’ hormone controlling growth and reproduction. However, a new multi-hormone model is presented here that integrates the environmental and endocrine control of reproduction. This is supported by evidence from in vitro bioassays. The juvenile hormone is shown to be heat stable and cross reactive between species. In addition, a second neuro-hormone, identified here as a gonadotrophic hormone, is shown to be present in mature females and is found to promote oocyte growth. Furthermore, dopamine and melatonin appear to switch off the juvenile hormone while serotonin and oxytocin promote oocyte growth. Global warming is likely to uncouple the phase relationship between temperature and photoperiod, with significant consequences for Nereidae that use photoperiod to cue reproduction during the winter in northern latitudes. Genotypic adaptation of the photoperiodic response may be possible, but significant impacts on fecundity, spawning success and recruitment are likely in response to short-term extreme events. Endocrine-disrupting chemicals may also impact on putative steroid hormone pathways in Nereidae with similar consequences. These impacts may have significant implications for the functional role of Nereidae and highlight the importance of comparative endocrinology studies in these and other invertebrates.

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“…Consequently, Rees (1997) and Rees & Olive (1999) conclude that temperature and photoperiod both influenced oocyte development in N. virens.…”

Section: The Role Of Photoperiod and Temperature On Reproduction In Nmentioning

confidence: 99%

The endocrine control of reproduction in Nereidae: a new multi-hormonal model with implications for their functional role in a changing environment

Lawrence

Soame

2009

Phil. Trans. R. Soc. B

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“…data). It has been demonstrated that a key event is the response to a critical photoperiodic threshold in the autumn (Olive et al 1998, Rees & Olive 1999 though the time of breeding may also be modified by the environmental conditions experienced after the time of this key transition (Rees & Olive 2000).…”

Section: Discussionmentioning

confidence: 99%

Pre-emptive competition as a selective pressure for early reproduction in the polychaete Nereis virens

Lewis¹,

Olive²,

Bentley³

2003

Mar. Ecol. Prog. Ser.

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Reproduction in the semelparous polychaete Nereis virens occurs at a time of year when seawater temperatures are lower than the optimum temperatures for fertilization and larval development and at a time when seawater temperatures are rising. This study assesses the possible role of intra-specific competitive interactions between settling N. virens post-larvae as a selective pressure for 'early' reproduction. A series of laboratory competition experiments were conducted between 2 cohorts of N. virens post-larvae, under a range of environmental conditions. Significant pre-emptive competition between settling post-larvae was recorded at 15°C, whereby a survival advantage was gained via prior residence with early larval settlers out-competing later arrivals. This competitive interaction was reduced at lower temperatures and no significant effect was measured at 5°C. An increase in age difference between the 2 cohorts of post-larvae increased the competitive effect, whilst photoperiod regime and food availability had no significant effect on the outcome of these experiments. Intra-specific competition was greatest at the temperatures at which maximum fertilization and development are known to occur, but was reduced at the temperature range at which spawning occurs in the field. It is suggested, therefore, that pre-emptive competition between settling post-larvae forms a strong selective pressure for breeding early at a time of year when temperatures are below the optimum for fertilization and development. KEY WORDS: Polychaeta · Pre-emptive competition · Nereis virens · Seasonal reproductionResale or republication not permitted without written consent of the publisher

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“…Photoperiodic responses play an important role in the control of sexual reproduction of Nereis virens Olive et al, 1998;Rees and Olive, 1999) and a number of other phylodocid polychaetes (Clark, 1988;Franke, 1986;Garwood, 1982). In addition to the transduction of photoperiodic information (relative duration of photophase and scotophase), there is also evidence of long-term circa-annual cycling (Olive, 1995) or at least the operation of long-period interval timing capability .…”

Section: Long-term Biorhythmicity and Seasonal Reproductionmentioning

confidence: 99%

Dancing to the rhythms of geological time: the biorhythm capabilities of Polychaeta in a geological context

Olive¹,

Kyriacou

Kramer³

et al. 2005

Invertebrate Reproduction & Development

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Errant polychaete worms in the Orders Eunicida (family Eunicidae) and Phyllodocida (families Nereidae and Polynoidae) exhibit a highly developed biorhythmic capability. The Pacific palolo worms are well known for a precisely timed annual breeding event in which mass spawning occurs at a particular time of day, on one day per year, that day having a fixed relationship to the lunar period. Nereidae and Polynoidae exhibit photoperiodic responses that determine the breeding season by regulation of oocyte growth. Nereis virens shows short-term cycles of foraging activity; automated recording of these patterns has revealed four distinct behaviour rhythm phenotypes: circadian, tidal, lunidian and arrhythmic, the last phenotype being expressed during the photoperiod induced growth diapause. The Eunicids and Phyllodocids are represented in the fossil record by scolecodonts, their fossilised jaws. There was a major radiation of these polychaetes during the Ordovician and the earliest suggested polychaete fossils are from the Cambrian. The simultaneous expression of tidal and circadian rhythmicity is characteristic of intertidal animals and it is likely that this complex behavioural repertoire was found in the ancestors of modern terrestrial forms, such as tetrapods and arthropods, prior to their emergence onto land during the Carboniferous and Silurian periods at least 400 Ma. The period of the earth's rotation, and hence day length and tidal period, has long been known to be increasing, and additionally the moon to be retreating from the earth, due to the phenomenon of tidal friction caused by the gravitational interactions between the moon and the earth. These changes are significant over a geological time scale. Consequently, the length of day was substantially less (and the number of days in a year more) than at present in the Cambrian and Ordovician periods. Recent theoretical analysis of the period of the earth's rotation suggests that the day length prior to a critical period (t crit ) around 1800 Ma may have been stable, with a length of only 4 h. At that time a period of more rapid change in the dynamics of the rotation was initiated. The implications of this theory for the evolution of the biological clock are discussed.

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Photoperiodic changes influence the incorporation of vitellin yolk protein by oocytes of the semelparous polychaete Nereis (Neanthes) Virens

Cited by 24 publications

References 22 publications

The endocrine control of reproduction in Nereidae: a new multi-hormonal model with implications for their functional role in a changing environment

The endocrine control of reproduction in Nereidae: a new multi-hormonal model with implications for their functional role in a changing environment

Pre-emptive competition as a selective pressure for early reproduction in the polychaete Nereis virens

Dancing to the rhythms of geological time: the biorhythm capabilities of Polychaeta in a geological context

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