Nereid Worms Research Articles

FoxA expression pattern in two polychaete species, Alitta virens and Platynereis dumerilii: Examination of the conserved key regulator of the gut development from cleavage through larval life, postlarval growth, and regeneration.

foxA orthologs are involved in various processes from embryo patterning to regulation of metabolism. Since foxA conserved role in the development of the gut of errant annelids has never been thoroughly studied, we used a candidate gene approach to unravel the molecular profile of the alimentary canal in two closely related nereid worms with a trochophore-type lecithotrophic larva. The character of foxA expression in the two polychaetes was similar but not identical. The genes were successively activated first in blastoporal cells, then in the stomodeum, the midgut, and hindgut primordia, and in the cells of central and peripheral nervous system. Before the start of active feeding of nectochaetes, we observed a short phase of foxA expression in the entire digestive tract. After amputation of posterior segments, foxA expression was established de novo in the new terminal part of the intestine, and then in the developing hindgut and the anus. We discovered an early marker of endoderm formation previously unknown in errant annelids. Its expression dynamics provided valuable insights into the gut development. Comparative analysis of foxA activity suggests its primary role in gastrulation morphogenesis independently of its type and in midgut and foregut specification. Developmental Dynamics 248:728-743, 2019. © 2018 Wiley Periodicals, Inc.

The winter diet of theAtlanticPuffinFratercula arcticaaround theFaroeIslands

Most mortality of Atlantic Puffins occurs outside the breeding season but little is known about the species’ diet at that time. The stomach contents of 176 Puffins shot legally for food around the Faroe Islands between October and January in three winters were examined. The remains of 20 species of fish, six species of crustacea and single species of polychaete, chaetognathid and squid were identified. The most frequently recorded prey in terms of frequency of occurrence were 0 group (< 1 year old) Lesser SandeelAmmodytes marinus(82% of stomachs), followed by mesopelagic fish (52%), nereid worms (41%), Silver RocklingGaidropsarus argentatus(36%), crustacea (35%), large sandeel (32%) and other large fish (32%). In terms of calculated biomass, nereids (41%), large sandeel (23%) and other large fish (17%) made up the bulk of the diet but the latter two prey types were most important in energetic terms (46% despite accounting for only 9% of items). Stomach contents collected on the same day and location were significantly more similar than those collected on different dates and locations, suggesting that during the winter, Puffins are generalists, taking any prey they encounter.

Fishing bait worm supplies in Japan in relation to their physiological traits

Saito, H., Kawai, K., Umino, T. and Imabayashi, H. 2014. Fishing bait worm supplies in Japan in relation to their physiological traits. Memoirs of Museum Victoria 71: 279-287. � � Marketresearchwasconductedfrom�2009�to�2013�toinvestigatethesupplyoflivewormsforfishingbaitinJapan.� Weobtained�25�typesoflivefishingbaitworms,�including�16�speciesofpolychaete,�1�speciesofechiuran,�and�1�species� of sipunculid. These were divided into three groups according to their country of origin: 1) worms supplied from native populations,� fivespecies� (Perinereis wilsoni, Hediste diadroma, Kinbergonuphis enoshimaensis, Pseudopotamilla occelata, and Hydroides ezoensis), 2) worms supplied from both native and non-native populations, three species (Marphysa cf. iwamushi, Halla okudai, and Urechis unicinctus), and 3) worms supplied from non-native populations, 10 species�(Perinereis linea, Alitta virens, Nectoneanthes uchiwa, Namalycastis rhodochorde, Glycera nicobarica, Diopatra sugokai, Marphysa cf. tamurai, Marphysa cf. mossambica, Scoletoma heteropoda, and Sipunculus nudus). Salinities in which no mortality of nereid worms occurred was 5-35 psu in Alitta virens, 5-30 psu in Namalycastis rhodochorde, and 10-35 psu in Perinereis linea. Worms living in temperate areas had a wide temperature tolerance of 5-30 °C in Alitta virens, Perinereis linea, Glycera nicobarica, Marphysa cf. iwamushi, and Scoletoma heteropoda. Tropical species (Namalycastis rhodochorde and Marphysa cf. mossambica) could not survive above 20 °C.

Development and maturation in the nereidid polychaetes Platynereis dumerilii and Nereis succinea exposed to xenoestrogens

Few studies link biochemical, cellular and whole animal effects of toxic compounds with growth and reproductive output on invertebrate model organisms. Thus, we explore the effects of xenoestrogens on nereid worms. Larvae of Platynereis dumerilii exposed to estradiol (E2) ethynylestradiol (EE2) and nonyplhenol (NP) observing the effects on growth, primordial germ cell (PGC) proliferation and maturation. In addition, a single exposure study was performed with a 50days latency period on adult worms of Nereis succinea. Since reduced glutathione (GSH) is required in detoxification of NP and is the precursor of the spawning pheromone nereithione (CSSG) in N. succinea, we analysed how the estrogenic chemical NP affects GSH concentrations. PGC were not affected by exposure to E2 and EE2 from 24hpf to 6days. Chronic exposure of P. dumerilii with NP over the full life cycle did not influence segment proliferation. Mature females that developed, even at high concentrations, were able to spawn and successful fertilization occurred. However, at high NP levels no P. dumerilii males matured. A significant decline of GSH can be seen in N. succinea males upon treatment with NP, but not in females, indicating that females stabilize GSH levels even in stress situations. This study shows some results that link the foundation to causally integrate toxic exposure to xenoestrogens with development, growth and reproductive outputs in nereidid polychaetes.

Prey abundance and habitat use by migratory shorebirds at coastal stopover sites in Connecticut

Stopover areas are vital for the successful migration of many species of shorebirds, as they, in part, allow individuals to deposit large quantities of fat needed to fuel their northward and southward journeys. While much research has focused on bird migration, few studies closely examine the environmental characteristics of specific stopover areas. For our study, we conducted prey availability surveys and documented shorebird habitat use during northward summer migration for three historically important stopover areas along the Connecticut Long Island Sound coastline in 2000. Coastal Connecticut provides important habitat not only for shorebirds migrating from northern Canada to South America, but also for resident breeding shorebirds (e.g., oystercatchers, plovers, and sandpipers). Our prey availability surveys indicate that all three stopover sites were characterized by some combination of polychaete worms, crustaceans, and mollusks. Polychaete worms of the family Neredidae were the most common prey item at two of the three sites. In addition, the site frequented by the greatest densities of shorebirds also had the greatest density of nereid worms and the greatest diversity of invertebrates. In terms of habitat use, our results indicate that foraging densities tended to be highest on intertidal habitats that were sheltered from coastal wave action and where densities of benthic (burrowing) and epifaunal (surface-dwelling) prey tended to be high. However, some shorebird species, including one breeding resident, the American Oystercatcher (Hae- matopus palliatus) and one migrant, the Ruddy Turnstone (Arenaria interpres), both of special management concern, favored foraging on beach-front habitats. In contrast to foraging habitat preferences, shorebirds roosting at high tidal phases showed strong preferences for beach habitats fronting the Long Island Sound. The use of beach-front habitats for both foraging and roosting poses a challenging situation for beach managers.

Small-scale disturbance and increased nutrients as influences on intertidal macrobenthic assemblages: experimental burial of wrack in different intertidal environments

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 241:29-39 (2002) - doi:10.3354/meps241029 Small-scale disturbance and increased nutrients as influences on intertidal macrobenthic assemblages: experimental burial of wrack in different intertidal environments F. Rossi*, A. J. Underwood Centre for Research on Ecological Impacts of Coastal Cities, Marine Ecology Laboratories A11, Science Road, University of Sydney, New South Wales 2006, Australia *E-mail: frossi@bio.usyd.edu.au ABSTRACT: Wrack (dead, washed-up seaweed and seagrass) buried in soft substrata causes increased organic content and alters the physical structure of sediments. These effects may influence the types and relative abundances of species in the sediment. Such influences can be expected to vary according to the type and organic content of the sediment. In this study, wrack was buried in 3 mudflats and 2 intertidal sandflats (with coarser sediments) in Botany Bay (New South Wales, Australia). The experiments tested the hypotheses that burial of wrack would (1) increase the content of total nitrogen (N) and organic carbon (OC) of sediments; (2) increase the biomass of micro-algae; and (3) alter the abundances of macrofauna in the sediments. Simulated wrack (equivalent amounts of plastic ribbon, without any organic content) was added to other experimental plots to test the above hypotheses when only physical disturbance, not organic enrichment, occurred. Total OC, N and chlorophyll a (chl a) were sampled every 2 wk for 6 wk and macrofauna were sampled after 6 wk. Some taxa (capitellid, orbinid and nereid worms) increased abundances where wrack was added. Nereidae, however, responded only in muddy sediments. The physical structure associated with wrack also caused an increase in numbers of Oligochaeta and increased patchiness in numbers of the soldier-crab Mictyris longicarpus, but only in sites where they were already abundant. Wrack represents a source of food for some taxa. Physical disturbance due to burial of wrack also adds to patchiness and abundance of taxa on sandy and muddy intertidal shores. The major responses of fauna predicted from other studies did not occur. KEY WORDS: Botany Bay · Buried wrack · Disturbance · Macrofauna · Nutrients Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 241. Online publication date: October 04, 2002 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2002 Inter-Research.

Recruitment in the Holothurian Cucumaria frondosa in the Gulf of Maine

Summary The sea cucumber Cucumaria frondosa spawns in the spring, in the Guff of Maine, USA. The larvae remain pelagic for several weeks prior to recruitment to the benthos. In the western Gulf of Maine, a previous study showed that juvenile C. frondosa occur exclusively inside mussel beds; adults are absent from the region. In the present investigation, recruitment and juvenile abundances in the field were examined from 1993–1995. A study conducted in the spring of 1993 in the Maine-New Hampshire coastal waters indicated that recruitment of C. frondosa to mussel beds was high. In the fell of 1994, no recruits were present on the benthos; juveniles were more abundant in coralline algae than in mussel beds or kelp holdfasts. In 1995, recruitment and juvenile abundance monitored over the recruitment season revealed that recruitment was highest in June. Toward the end of June and during early July, recruitment was significantly higher in mussel beds than in coralline algae and kelp holdfasts. In June, a 2-day intensive field study indicated that recruits were significantly more abundant in mussel beds than in kelp holdfasts or coralline algae, while juveniles were significantly more abundant in the mussel beds than coralline algae. Mussel beds may enhance early survival by providing a refuge from predation. A potential predator on new recruits are large nereid worms.

Distribution of shorebirds at the Berg River estuary, South Africa, in relation to foraging mode, food supply and environmental features

Foraging densities of Curlew Sandpipers Calidris ferruginea and Grey Plovers Pluvialis squa‐tarola at the Berg River estuary, South Africa, are examined in relation to prey and habitat attributes.There is a substantial overlap in the prey species eaten by Curlew Sandpipers and Grey Plovers, but the distribution patterns of the two species within the estuary could not be explained by the same prey attributes.The distribution of tactilely foraging Curlew Sandpipers was determined largely by the numerical abundance of nereid worms. They foraged preferentialiy on muddy rather than sandy substrata, but their distribution could not be explained on the basis of substratum penetrability. The density of visually foraging Grey Plovers was correlated with the biomass, rather than abundance, of the larger of the two common nereids on the estuary. The favoured foraging area of Grey Plovers had a high vegetation cover, but their foraging dispersion was not influenced by substratum type.The energy intake rates of Curlew Sandpipers were broadly inversely related to their foraging density, although the rate of prey capture was maximal at high prey density. These birds may use neighbour success rates in selecting foraging sites. Energy intake rates of Grey Plovers were very consistent across the estuary, suggesting that individuals occupy or defend areas which provide access to comparable food resources.

Intense predation cannot always be detected experimentally: A case study of shorebird predation on nereid polychaetes in South Africa

The effect of predation by curlew sandpipers Calidris ferruginea L. and grey plovers Pluvialis squatarola (L.) on populations of nereid worms Ceratonereis keiskama (Day) and C. erythraeensis (Fauvel) was studied at the Berg River estuary, South Africa, by comparing observations of shorebird-foraging intensity with the results of a population study of two species of nereid worms within and outside bird exclosures. The study was carried out during the four-month period prior to northward migration of shorebirds. Population structure of the two nereid species differed considerably. Ceratonereis keiskama reproduced earlier than C. erythraeensis and only young individuals were present during the study. By contrast, old C. erythraeensis were available to the birds at the start of the experiment and young animals entered the population during the experiment. Despite selective predation on certain size classes of nereids by the birds, no significant changes in the population structure of either nereid were detected by the cage experiment. Numbers and biomass of both Ceratonereis spp. in paired controls and cages tracked each other and did not diverge as predicted. A consistent difference in the depth stratification of the two nereids may, however, have been due to predation pressure. Curlew sandpipers were calculated to remove 3112 nereids per m 2 during the three months, equivalent to 4.4. g (dry weight) per m 2. This represents 58% of the initial numbers and 77% of the initial biomass of nereids. Although predation on nereids by waders was exceptionally high at the Berg River estuary, any depletion in numbers or biomass of nereids caused by these predators was masked by the reproduction of the nereids. The fact that the predators' high energy requirements prior to northward migration coincide with the period of peak production of invertebrate prey makes the Berg River estuary an exceptionally favourable wintering area.

Further studies on the phylogenetic distribution of pyruvate oxidoreductase activities

1. 1. The phylogenetic distribution of lactate, octopine, alanopine and strombine dehydrogenase activities (respectively, LDH, ODH, ADH and SDH) was examined in over 60 species from seven phyla and from three continents. 2. 2. The results confirm and extend previously published data. Consistencies of distribution are observed at the levels of phyla, class, order and family. 3. 3. Major observations include prominent SDH in the Porifera; LDH only in the Polyplacophera, Nudibranchia and Myidae (Mollusca) and nereid worms (Polychaeta); ODH and SDH in the marine pulmonate Melampus bidentatus (Basommatophora); high ADH to SDH ratios in marine gastropods; high ODH in active molluscs; and apparent SDH in the barnacle Lepas anatifera. 4. 4. The results are discussed in relation to theories of opine pathway evolution and the newly discovered tauropine and β-alanopine opine dehydrogenases.

Isozyme Variation in Three Nereis Species from Five Localities in the U.K.

The taxonomy of marine worms belonging to family Nereidae is still in an uncertain state. There are many species, like Nereis diversicolor Müller, N. japonica Izuka and N. limnicola Johnson, which are morphologically similar but have different reproductive habits. Clark (1977) reviewed many examples of reproductive isolation without morphological differentiation in polychaetes including members of the family Nereidae. He also stressed the need for detailed study in such polychaetes where taxonomic confusion exists.Electrophoretic techniques have contributed a great deal in solving taxonomic problems (see Avise, 1975 and Burton, 1983). All electrophoretic methods have proved useful to varying degrees in characterizing specific organisms. In particular, acrylamide gel electrophoresis has seen extensive use because it has excellent resolving power (Brewer, 1970). Studies of the electrophoretic variation of nereid isozymes have not been reported, except by Jones (1970), who examined various polychaetous annelids for the presence of certain dehydrogenases. This present report contains preliminary observations concerning the applicability of isozyme electrophoresis to the study of nereid worms.

The response of marine worms to unilateral tension of their musculature.

It has been shown that in Lumbricus1 and Nereis2 the anterior segments of the animal respond to passive bending of the posterior part, by active turning of the head in a direction parallel with the new orientation of the tail. This has been termed the homostrophic reflex. The receptors for the reflex are distributed throughout the animal but the efferent nerves are limited in their origin to the anterior 20 segments in Lumbricus, and to the first 2 or 3 segments in Nereis. The afferent impulses travel forward by way of the ventral nerve cord. Bending of the head end does not affect the direction of backward locomotion, hence the mechanism of the homostrophic reflex exhibits polarity. Similar observations3 have been recorded for Diplopods and for the larvae of Tenebrio molitor.A systematic study has shown the homostrophic reflex to play a part in the behavior of a number of nereid worms of the Mediterranean, namely, Eunice gigantea, Eunice siciliensis, Holla parthenospeia, Nephthis scolopendroides, Sthenela...