Life cycle, weight and possible age distribution in a population of<i>Nereis virens</i>(Sars) from New Brunswick

Snow, Doreen R.; Marsden, Joan R.

doi:10.1080/00222937400770431

Cited by 22 publications

(21 citation statements)

References 8 publications

(17 reference statements)

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“…Nereis (Neanthes) virens is indeed one of the largest and potentially longest lived of the marine annelids (Olive et al 1998) and, as in most Nereidae, the generation time is greater than the phase length of the breeding cycle. Therefore the proportion of sexually mature worms in the population at the time of breeding will be less than unity as observed in natural populations of N. virens (Snow & Marsden 1974, Creaser et al 1983, Olive 1993. The mean generation time is itself a response to environmental factors and in N. virens is decreased under intensive culture.…”

Section: Seasonality and The Semelparous Life Cyclementioning

confidence: 99%

Influence of photoperiod and temperature on oocyte growth in the semelparous polychaete Nereis (Neanthes) virens

Olive¹,

Rees²,

Djunaedi³

1998

Mar. Ecol. Prog. Ser.

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Environmental factors influencing the rate of oogenesis in the seasonal cycle of the semelparous polychaete Nereis (Neanthes) virens Sars have been investigated in specimens reared under commercial conditions (concrete tanks under natural light supplied with a mixture of power station heated and ambient sea water to maintain ca 18°C all year round). The rate of oocyte growth is strongly influenced by the external photoperiod and the responses to static 24 h LD (light-dark) cycles have been investigated. Oocyte growth is more rapid when specimens are exposed to a 24 h LD cycle in which the photophase is below a critical value between 1 2 and 13 h The critical photopenod transition in natural environments is therefore at the autumn equinox hr. rJirens are able to respond to transfer between LD 16:8 h and LD 8 16 h at all times of the year, which suggests the operation of a continuously consulted system of photoperiod~c control. The rate of oocyte growth in co~llpetent specimens is a 11near function of the number of LD 8-16 h cycles experienced. The critical photopt!riod divides the solar year into 2 nearly equal periods, with the short day period (winter) favouring oocyte growth. There is a synergism between the effects of photoperiod and seasonally reducing temperature. During the cdlendar winter transition to LD 8:16 h or other LD cycles below the critical value initiates rapid oocyte growth whatever the temperature but in the calendar summer this only occurs if the external temperature is also reduced to 12OC or below. The response to photoperiod and temperature is moderated by internal factors and under commercial production systems elevated rates of oocyte growth can only be achieved in females that are about 1 yr old. The oocyte growth induced by exposure to LD 8:16 h light cycles and low temperature is similar to, but slightly less than, that induced by hormone depnvatlon, i.e. supra-oesophageal ganglion ablation. The results are discussed in relation to the control of seasonal cycles in Nereidae, the role of the endocrine system and ~n the context of the life history theory for long lived semelparous organisms with variable age at maturity

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Section: Seasonality and The Semelparous Life Cyclementioning

confidence: 99%

Influence of photoperiod and temperature on oocyte growth in the semelparous polychaete Nereis (Neanthes) virens

Olive¹,

Rees²,

Djunaedi³

1998

Mar. Ecol. Prog. Ser.

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“…Populations of N. virens in the St. Lawrence Estuary (Desrosiers et al 1985(Desrosiers et al , 1991(Desrosiers et al , 1994 and in New Brunswick (Snow & Marsden 1974) are confined in their timing of reproduction by the time of the ice melt, so spawning does not normally occur until May to June. UK populations breed in February and March (Brafield & Chapman 1967, Bass & Brafield 1972.…”

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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“…1. The age estimates shown on this figure are correlates of size and breeding condition and are taken from an account of population structure in a New Brunswick population of Nereis virens (Snow and Marsden 1974 (Table I ) 32P-labelled phospholipids were first found in detectable amounts at 3 h after injection. In these experiments PI carried the strongest, and in some cases the only detectable label.…”

Section: <2 Y E a R S <4 Y E A R S <5 Y E A R S W O R M W E I G H T Gmentioning

confidence: 99%

“…only neural tissue, was used for extraction. Nereis virens used in this study were considered to fall into the following four categories, differing in the interrelated (Snow and Marsden 1974) features of size, age, and stage of sexual maturity. (1) Very small worms, 2 g or less in weight; sexually undifferentiated with an average brain weight of 0.05 mg. (2) Medium-sized worms, sexually immature; 2.3 g in weight; gametes developing in the coelomic cavity; average brain weight 0.15 mg. (3) Large immature worms, 3-5.5 g in weight; gametes developing in the coelomic cavity; average brain weight 0.3 mg. (4) Mature animals; ripe gametes in the coelomic cavity; average brain weight 0.45 mg.…”

Section: <2 Y E a R S <4 Y E A R S <5 Y E A R S W O R M W E I G H T Gmentioning

confidence: 99%

The radiotracer labelling of the phospholipids of the brain of Nereis virens (Polychaeta) in very young and older animals

Marsden¹,

Jost²

1975

Can. J. Zool.

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MARSDEN, J. R., and J. JOST. The radiotracer labelling of the phospholipids of the brain of Nereis virens (Polychaeta) in very young and older animals. Can. J. Zool. 53: 278-284. The uptake of 32P from H332P04 has been measured in the phospholipids of the supraoesophageal ganglion of the polychaete Nereis virens. In vivo injections at 3 and 6 h before dissection show a more extensive incorporation of tracer into phosphatidylinositol than into any other phospholipid. In young sexually undifferentiated animals the radioactivity in phosphatidylinositol at 6 h is about 13 times that in mature animals. Turnover of phosphatidic acid is also high. This and other aspects of phosphatidylinositol metabolism in Nereis brain are shown to be very like that characteristic of stimulated secretory tissue in birds and mammals. It is suggested that these phenomena may be related to hormone secretion by the brain of N . virens. MARSDEN, J. R., et J. JOST. 1975. The radiotracer labelling of the phospholipids of the brain of Nereis virens (Polychaeta) in very young and older animals. Can. J. Zool. 53: 278-284. On a mesurk l'accumulation de 32P partir d'HPP04 dans les phospholipides du ganglion supraoesophagien, chez le polychbte Nereis virens. Des injections in vivo, 3 et 6 h avant la dissection, revtlent que le marqueur s'incorpore plus au phosphatidylinositol qu'8 tout autre phospholipide. Chez les jeunes polychbtes dont le sexe n'est pas encore differencik, la radioactivite du phosphatidylinositol aprbs 6 h est 13 fois plus Blevee que chez les animaux en pleine maturite. Le taux de remplacement de I'acide phosphatidique est &lev6 egalement. Le mktabolisme du phosphatidylinositol dans le cerveau de Nereis s'avbre, sous cet aspect et a d'autres points de vue, tres semblable au tissu sbcreteur stimult des oiseaux et des mammiferes. Ces phenomenes pourraient itre relies a la secretion d'hormone par le cerveau chez Nereis virens . [Traduit par le journal] IntroductionIn an earlier study of the phospholipids of the supraoesophageal ganglion, or brain, of the polychaete Nereis virens (Marsden 1971), it was shown that activity, as represented by incorporation of 32P-orthophosphate, was high in the phospholipids of the brain of young animals and low in sexually mature animals. In animals of intermediate age, 32P incorporation, as recorded by X-ray plate radioautography of thin-layer chromatographic plates, was confined to phosphatidylinositol and its precursor, phosphatidic acid. It was suggested that these results might indicate a "phospholipid effect" in the Nereis brain, a hyperactivity in the turnover of phosphatidylinositol which is characteristic of stimulated secretory tissues (Hokin and Hokin 1958;

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Life cycle, weight and possible age distribution in a population ofNereis virens(Sars) from New Brunswick

Cited by 22 publications

References 8 publications

Influence of photoperiod and temperature on oocyte growth in the semelparous polychaete Nereis (Neanthes) virens

Influence of photoperiod and temperature on oocyte growth in the semelparous polychaete Nereis (Neanthes) virens

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

The radiotracer labelling of the phospholipids of the brain of Nereis virens (Polychaeta) in very young and older animals

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