scholarly journals Rissoid Larvæ as Food of the Young Herring. The Eggs and Larvæ of the Plymouth Rissoidæ

1934 ◽  
Vol 19 (2) ◽  
pp. 523-539 ◽  
Author(s):  
Marie V. Lebour
Keyword(s):  
Yolk Sac ◽  
Great Abundance ◽  
Free Swimming ◽  
Large Numbers ◽  
Inshore Waters ◽  
Eggs And Larvae

The free-swimming young of the Rissoidse are particularly important in the plankton for there is always one or more species present in any month and they usually occur in great abundance. The various species live between tide-marks, in the laminarian and coralline zones and in deeper water in several fathoms depth; wherever tow-nettings are taken they usually contain some species of this family. The inshore waters, however, are the richest in rissoids. Even in winter certain species are common round the Plymouth coasts. Some years ago it was found that very young herring just before losing the yolk-sac and about a fortnight old had been eating small rissoids, evidently almost newly hatched (Plate I, Fig. 1). The herring up to a length of about 12 mm. and just after the yolk-sac had disappeared altogether continued to eat them but usually after this size they ate only small Crustacea. From 1917 to 1921 it was found that out of 140 young herring examined, 91 had fed on these small gastropods. In later years they were also found feeding on them (Lebour, 1921, 1924). Other minute planktonic organisms were eaten, including algæ, tintinnids, copepod and cirripede nauplii and very small adult copepods; also a minute bivalve larva but no other gastropod, although other veligers were present in the plankton, Patella being specially common. The young herrings hatch out from December to February, therefore these little gastropods must also hatch at this time and this proves to be the case for in the plankton there are large numbers of these very young veligers (Plate I, Figs. 7–8). Later on, in spring, older stages of the same mollusc abound and are quite the commonest veligers in the plankton near the coast (Plate I, Figs. 17–19). In the summer they have almost entirely disappeared.

Note on Injury to Tree Fruits by Frankliniella tritici (Fitch) (Thysanoptera: Thripidae)

1955 ◽  
Vol 87 (6) ◽  
pp. 238-239 ◽  
Author(s):  
H. R. Boyce
Keyword(s):  
Sweet Cherry ◽  
Immature Stages ◽  
Great Abundance ◽  
Essex County ◽  
Large Numbers ◽  
Tree Fruits

The thrips Frankliniella tritici (Fitch) occurred in great abundance early in May, 1954, in orchards of tree fruits in Essex County, Ontario.Observations during the first three weeks of May showed that this insect was abundant on the foliage and blossoms of apple, sweet and sour cherries, plum, and peach. Sweet cherry, European plum, and peach suffered the greatest attack. On sweet cherry and plum large numbers of eggs were inserted in blossom stems, styles and apices of the ovaries. From 30 to 50 per cent of the blossoms of sweet cherry and plum were destroyed, apparently because of disruption of tender tissues by the large numbers of eggs inserted in them; a considerable number of the fruits remaining on the trees were injured by feeding of adults and immature stages of the thrips (Fig. 1).

scholarly journals THE IMPACT OF THE SEA EMPRESS OIL SPILL ON BIRDS OF THE PEMBROKESHIRE COAST AND ISLANDS

1997 ◽  
Vol 1997 (1) ◽  
pp. 217-225
Author(s):  
Stephen J. Parr ◽  
Robert J. Haycock ◽  
Malcolm E. Smith
Keyword(s):  
Oil Spill ◽  
Sublethal Effects ◽  
Poor Quality ◽  
Adult Survival ◽  
Bird Populations ◽  
Seabird Colony ◽  
Large Numbers ◽  
International Importance ◽  
Inshore Waters ◽  
The Impact

ABSTRACT Much of the Pembrokeshire coast and islands, together with its inshore waters, are of international importance for their breeding seabirds and wintering seaduck. Although the Sea Empress oil spill occurred before the breeding season, some 7000 oiled birds were recovered dead or alive. The impact of the oil spill on birds can be classified as follows: immediate mortality especially of more than 4500 wintering common scoter in Carmarthen Bay; sublethal effects on productivity of colonies and reduced adult survival from oil or dispersant ingestion; and chronic effects on bird populations from long-term pollution, particularly of prey. A range of monitoring and research projects are under way to investigate the impact, but it is premature to provide many results. The oil spill probably caused significant local declines in seabird colony sizes, especially of guillemot. The impact on common scoter will prove difficult to determine because of the poor quality and high variability of preincident data. Large numbers of oiled birds, particularly common scoter, were treated and subsequently released. The successful rehabilitation of such released birds is controversial; research and review results will be reported.

scholarly journals Greenhouse Whitefly Control of Salvia, 1997

1998 ◽  
Vol 23 (1) ◽  
pp. 356-357
Author(s):  
D. R. Smitley ◽  
T. W. Davis ◽  
M. M. Williams
Keyword(s):  
Irrigation System ◽  
Michigan State University ◽  
State University ◽  
Greenhouse Whitefly ◽  
Large Numbers ◽  
Untreated Check ◽  
History Of ◽  
Pre Treatment ◽  
Eggs And Larvae ◽  
Clay Pots

Abstract Salvia plants were started from seeds in 25" X 14" tubs at the Pesticide Research Center greenhouses at Michigan State University on 7 May. These 3 tubs were surrounded by fully grown zinnia plants that had large numbers of white-fly. The larger Zinnia plants had previously been placed in a research greenhouse with a long history of whitefly problems. After the Salvia from the tubs grew to approximately 1 to 2 inches, they were replanted into individual 6" clay pots. The plants were irrigated with 120 mL of water daily, with a drip irrigation system. Plants were also fertilized with Peters 20-20-20 at 1000 ppm biweekly. Pre-treatment counts were made on 19 Jun by taking five leaves per plant and counting the number of eggs and larvae on the bottom of the leaves using a dissecting scope. Treatments were blocked by using an adjusted precount. The adjusted precounts represented 33% of the eggs added to the total number of larvae. Each treatment was replicated 6 times. Due to the number of treatments, the test was arranged in several blocks, each with an untreated check. Single application granular treatments were all applied on 25 Jun and spray applications were applied on 25 Jun, 2 Jul, and 9 Jul. A hand-held R&D CO2 sprayer with an 8003 nozzle at 50 psi was used. Whitefiles were counted by collecting leaves on 2 Jul, 17 Jul, 22 Jul and examining in the same manner as for the precounts.

Mechanized extraction of arthropods from cattle dung

1987 ◽  
Vol 77 (2) ◽  
pp. 239-246 ◽  
Author(s):  
R. W. Sutherst ◽  
A. Macqueen ◽  
B. M. Kelley ◽  
D. A. Stegeman ◽  
K. G. Asher ◽  
...  
Keyword(s):  
Large Scale ◽  
Motor Drives ◽  
Cattle Dung ◽  
Community Studies ◽  
Electric Motor Drives ◽  
Fine Mesh ◽  
Large Numbers ◽  
Arthropod Fauna ◽  
Eggs And Larvae ◽  
Dung Sample

AbstractEcological, population and community studies of arthropod fauna inhabiting dung require large-scale quantitative data to produce statistically adequate results. A mechanized extraction technique is described which recovers fauna accurately and rapidly from large numbers of cattle dung pads. The equipment comprises a motor-driven paddle which agitates the dung sample in a bucket with fine mesh panels inlaid into its walls and through which is passed a continuous flow of water. An electric motor drives five such units simultaneously. Most dipteran puparia and adult arthropods float on water and are recovered following the washing. Puparia are recovered manually, while mites and adult beetles are extracted from the floating debris with heat in modified Berlese-Tullgren funnels. The wash bucket and its drained contents are then immersed in a flotation vat through which a sodium carbonate solution is recirculated. Insect eggs and larvae are floated off into sieves and rinsed before preservation. The resulting samples are fixed and preserved in 70% ethanol for later identification and counting. The procedure recovered 70–90% of most types and stages of dung fauna. Up to 25 complete dung pads can be processed per day with a team of three people.

' Bacillus piliformis ' (Tyzzer) and Tyzzer’s disease of the laboratory mouse I. Propagation of the organism in embryonated eggs

1966 ◽  
Vol 165 (998) ◽  
pp. 35-60 ◽  
Keyword(s):  
Epithelial Cells ◽  
Laboratory Mouse ◽  
Serial Passage ◽  
Yolk Sac ◽  
Liver Lesions ◽  
Hepatic Cells ◽  
Large Numbers ◽  
Significant Difference ◽  
Hepatic Lesions

A contagious disease of laboratory mice characterized by focal necrotic lesions of the liver was first described by Tyzzer (1917). This author described a pleomorphic sporing organism associated with the disease and called it ' Bacillus piliformis '. He found it intracellularly in hepatic cells bordering the necrotic foci and also in epithelial cells of the large intestine of mice showing liver lesions. Many cells contained large numbers of organisms, and Tyzzer concluded that multiplication was intracellular. B . piliformis has not been cultivated on bacteriological media and hitherto the only sources available for experimental study of Tyzzer’s disease have been infected mouse liver and brain. With such material it is difficult to produce liver lesions in mice by parenteral injection unless the animals are treated with cortisone. This communication describes the isolation and serial passage of two strains of B . piliformis in embryonated eggs. One strain was propagated for 30 serial passages, 26 of which were made in eggs by yolk sac injection and the others in mice. A non-sporing variant obtained from this strain produced hepatic lesions in embryos and mice similar to those produced by the parent sporing strain. No evidence was obtained of extracellular growth of the organism and intracellular growth occurred almost exclusively in epithelial cells of the yolk sac endoderm and hepatic cells of the embryo. Although pleomorphic, B . piliformis has a distinctive morphology which was described in detail by Tyzzer. All the forms described by this author were observed in embryonated eggs. The vegetating form of the organism rapidly lost its infectivity in vitro and also in the egg following death of the embryo. This loss of infectivity proved a limitation to certain in vitro studies and no method of halting it in the fluid state was discovered. However, it proved possible to obtain sufficient survival of the non-sporing strain for inoculation purposes by preserving crude tissue suspensions at – 75 °C. The spores survived heating at 56 °C but were usually inactivated at 65 °C. They survived well at room temperature and the organism was recovered by mouse and egg passage from inoculated eggs kept at this temperature for over a year. Penicillin was found to be highly effective in halting the progress of infection in eggs. In the course of the work there were indications of a cyclic variation in the susceptibility of embryonated eggs to infection, and on one occasion a significant difference was demonstrable between eggs obtained from different pens. The results obtained when yolk sac and chick embryo liver infected with B . piliformis were injected into mice are described in the following paper (Craigie 1966).

scholarly journals Some features of embryonic development of eggs and larvae of three stripe rockfsh Sebastes trivittatus (Sebastidae) at Primorye (Japan Sea)

2018 ◽  
Vol 195 ◽  
pp. 146-150
Author(s):  
V. P. Gnyubkina ◽  
A. I. Markevich
Keyword(s):  
Embryonic Development ◽  
Water Temperature ◽  
Japan Sea ◽  
Yolk Sac ◽  
Internal Layers ◽  
External Layer ◽  
Frontal Part ◽  
June July ◽  
Late Stages ◽  
Eggs And Larvae

Later embryonic development ofSebastes trivittatuspasses in 20 days under water temperature 10 оС (in June-July). During this period, the embryos ofS. trivittatusincrease in diameter from 0.1 mm to 1.3 mm and change their shape from spherical to elliptical. Within gonads of pre-hatching females, the embryos have different stages: from prelarvae on late stages of development in the internal layers to pre-hatching larvae in the external layer. The pre-hatching larva hasTL4.1 mm, 5–6 melanophores on the top of head, 20 melanophores in ventral row, some melanophores on peritoneum, and oil globule in the frontal part of intestine; its notochord is not flexed, yolk sac is absent, body myotomes are poor visible, number of tail myotomes is 24.

The Abundance and Distribution of Eggs and Larvae of Teleost Fishes off Plymouth in 1969 and 1970: Part 3. Eggs of Pilchard (Sardina Pilchardus Walbaum) and Sprat (Sprattus Sprattus (L.))

1974 ◽  
Vol 54 (2) ◽  
pp. 333-353 ◽  
Author(s):  
Neclâ Demir ◽  
A. J. Southward
Keyword(s):  
Water Column ◽  
Teleost Fishes ◽  
Sardina Pilchardus ◽  
Sampling Area ◽  
Average Volume ◽  
Sprattus Sprattus ◽  
Large Numbers ◽  
June July ◽  
Abundance And Distribution ◽  
Eggs And Larvae

Pilchard eggs were collected over a grid of 30 stations visited on 14 cruises from August 1969 to November 1970. The samples were taken with oblique tows of a 1 m terylene net at 4 knots, the average volume of water filtered being 750 m3. The formalin preserved eggs were graded into the series of stages described by Gamulin & Hure. No very early eggs were found, but from the occurrence of stage 2 eggs it is deduced that most spawning takes place in the early hours of darkness, between 20.00 and 24.00 h B.S.T.: some spawning must also occur all round the clock.There were two main peaks of spawning, June-July and October-November, when large numbers of eggs were found inshore; the average numbers reached 196 per m2 water column in July and 30 per m2 water column in October. Smaller numbers of eggs were taken in the other months of the year, mostly offshore, and with a minimum in December–February. In the spring (March-May) the area sampled was well clear of the main area of spawning of pilchard in the approaches to the Channel, north or northwest of Ushant.During the peak months no particular part of the sampling area appeared to be especially favoured for spawning.The significance of the two main peaks of spawning is discussed in relation to the problem of recruitment of fish to the population. As an alternative to the accepted hypothesis that young pilchard move back to the Bay of Biscay for maturation it is suggested that some of them, at least, may survive and mature in the Channel.

scholarly journals Spatio-temporal distribution of eggs and larvae of half-fin anchovy Setipinna taty (Valenciennes, 1848) in the inshore waters off Jiangsu, China

2019 ◽  
Vol 66 (1) ◽  
Author(s):  
Yan Jin ◽  
Zun-Lei Liu ◽  
Jian-Hua Tang ◽  
Yong Liu
Keyword(s):  
Fishery Management ◽  
Life Stage ◽  
Temporal Distribution ◽  
Early Life Stage ◽  
Additive Models ◽  
Significant Shift ◽  
Larvae And Juveniles ◽  
Inshore Waters ◽  
Spatio Temporal ◽  
Eggs And Larvae

Understanding the spatial distribution and environmental characteristics of fish spawning grounds is essential to design effective fishery management. The half-fin anchovy Setipinna taty (Valenciennes, 1848) plays an important role in the marine food web. A survey with 54 stations was conducted in 2014 to study the spatio-temporal distribution of eggs and larvae of half-fin anchovy around the inshore waters of Jiangsu, China. Half-fin anchovy eggs, larvae and juveniles were collected every month from April to July 2014. Generalised additive models were used to investigate the relationship between distribution of eggs, larvae and juveniles and environmental variables. A total of 4150 eggs and 685 half-fin anchovy larvae and juveniles were caught during the survey. During the spawning season, the highest egg densities were located in the inshore water area (121°-122°E, 32.5-33.5°N), with no significant shift in location of egg densities through time. The distribution of larvae and juveniles mostly overlapped with the egg distribution, suggesting that the early life stage of half-fin anchovy are distributed within the inshore waters of Jiangsu. The optimal water temperature, salinity and depth for eggs and larvae were in the range of 14.0-24.6°C, 28.7-29.8 ‰ and 15.9-17.4 m, respectively.

Flagellar Cooperativity and Collective Motion in Sperm

Fluids ◽  
2021 ◽  
Vol 6 (10) ◽  
pp. 353
Author(s):  
Julie Simons ◽  
Alexandra Rosenberger
Keyword(s):  
Collective Motion ◽  
Cooperative Behavior ◽  
Three Dimensional ◽  
Thin Structures ◽  
Free Swimming ◽  
Hydrodynamic Coupling ◽  
Large Numbers ◽  
Regularized Stokeslets ◽  
Group Velocities

Sperm have thin structures known as flagella whose motion must be regulated in order to reach the egg for fertilization. Large numbers of sperm are typically needed in this process and some species have sperm that exhibit collective or aggregate motion when swimming in groups. The purpose of this study is to model planar motion of flagella in groups to explore how collective motion may arise in three-dimensional fluid environments. We use the method of regularized Stokeslets and a three-dimensional preferred curvature model to simulate groups of undulating flagella, where flagellar waveforms are modulated via hydrodynamic coupling with other flagella and surfaces. We find that collective motion of free-swimming flagella is an unstable phenomenon in long-term simulations unless there is an external mechanism to keep flagella near each other. However, there is evidence that collective swimming can result in significant gains in velocity and efficiency. With the addition of an ability for sperm to attach and swim together as a group, velocities and efficiencies can be increased even further, which may indicate why some species have evolved mechanisms that enable collective swimming and cooperative behavior in sperm.

Nests of the black stork Ciconia nigra as a habitat for mesostigmatid mites (Acari: Mesostigmata)

Biologia ◽  
2009 ◽  
Vol 64 (5) ◽  
Author(s):  
Jerzy Błoszyk ◽  
Dariusz Gwiazdowicz ◽  
Bruce Halliday ◽  
Paweł Dolata ◽  
Bartłomiej Gołdyn
Keyword(s):  
Abundant Species ◽  
Predatory Mites ◽  
Mite Species ◽  
Preliminary Results ◽  
Large Numbers ◽  
Ciconia Nigra ◽  
Black Stork ◽  
Eggs And Larvae

AbstractWe surveyed the Mesostigmatid mite fauna of nests of the black stork Ciconia nigra, to determine the role of these mites in the biology of their hosts. We present preliminary results obtained on the basis of material collected from 31 nests. A total of 1,615 mite specimens was recorded, belonging to 39 species. The most abundant species were Dendrolaelaps strenzkei, Apionoseius infirmus, Macrocheles merdarius and Macrocheles ancyleus, which constituted more than 65% of all the specimens recorded. The presence of large numbers of predatory mites could be beneficial to the birds, if they feed on the eggs and larvae of the bird’s parasites. It is likely that many of the mite species found in these nests were carried there by phoresy on insects, mainly Coleoptera.

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