V - The development of Haliotis Tuberculata , with special reference to organogenesis during torsion

1937 ◽  
Vol 228 (552) ◽  
pp. 219-268 ◽  
Keyword(s):  
Nervous System ◽  
Special Reference ◽  
Larval Development ◽  
Retractor Muscle ◽  
Larval Life ◽  
Free Living ◽  
Larval Stages ◽  
Haliotis Tuberculata ◽  
New Interpretation ◽  
Selection Of

Investigation of the development of Haliotis tuberculata , Linnaeus, was undertaken as a natural sequel to an examination of the bionomics and anatomy of Haliotis (Crofts 1929, p. 159). It is an attempt to elucidate the organogenesis during the changing larval habits, in the hope of adding to the scanty ontogenetical evidence available towards solving the problems of gastropod evolution. Excellent accounts of the embryonic phase, including patiently worked out details of the cleavage and of gastrulation, have been published for Crepidula (Conklin 1897), Patella (Patten 1886; Wilson 1904; and Smith 1935), Trochus (Robert 1902), Physa (Wierzejski 1905), Dentalium (Wilson 1904). The only comprehensive accounts of gastropod larval development already published are of Paludina (Erlanger 1891; Tonniges 1896; Drummond 1902; Andersen 1924) and of Patella (Patten 1886; Smith I935). The accounts of Paludina elucidate the details of development of the coelom and its derivatives. The viviparous habit and consequent loss of free larval life in Paludina , however, make it a very unsuitable example of gastropod development. Evolutionary stages are more likely to be traced from the development of less specialized gastropods, an adequate selection of whose free-living larval stages can be obtained. The larval development of Patel, Acmaea, Trochus and Haliotis has been described, in varying completeness for the different genera. Patten’s work on Patella coerulea (1886) gives a description only of the beginning of organogenesis. After a lapse of fifty years a more detailed account of the development of P. vulgata has been given by Smith (1935). This work gives a new interpretation of the development of the mesoderm, of the muscles and of the nervous system. The dorsal retractor muscle of the larva, which Patten indicated for P. coerula , is shown in P. vulgata to be placed asymmetrically and torsion takes place “ under the action” of this muscle.

Neurogenesis in the thoracic neuromeres of two crustaceans with different types of metamorphic development

1998 ◽  
Vol 201 (17) ◽  
pp. 2465-2479 ◽  
Author(s):  
S Harzsch ◽  
J Miller ◽  
J Benton ◽  
RR Dawirs ◽  
B Beltz
Keyword(s):  
Embryonic Development ◽  
Larval Development ◽  
Neuronal Development ◽  
Temporal Patterns ◽  
Homarus Americanus ◽  
Spider Crab ◽  
Larval Life ◽  
Larval Stages ◽  
Metamorphic Development ◽  
Embryonic And Larval Development

The mode of embryonic and larval development and the ethology of metamorphosis in the spider crab and the American lobster are very different, and we took advantage of this to compare neuronal development in the two species. The goals of this study were to discover whether the differences in the maturation of the neuromuscular system in the pereopods and the metamorphic changes of motor behavior between the two species are reflected at the level of the developing nervous system ('neurometamorphosis'). Furthermore, we wanted to broaden our understanding of the mechanisms that govern neuronal development in arthropods. Proliferation of neuronal stem cells in thoracic neuromeres 4-8 of the lobster Homarus americanus and the crab Hyas araneus was monitored over the course of embryonic and larval development using the in vivo incorporation of bromodeoxyuridine (BrdU). Neuropil structure was visualized using an antibody against Drosophila synapsin. While proliferation of neuronal precursors has ceased when embryogenesis is 80 % complete (E80%) in the lobster thoracic neuromeres, proliferation of neuroblasts in the crab persists throughout embryonic development and into larval life. The divergent temporal patterns of neurogenesis in the two crustacean species can be correlated with differences in larval life style and in the degree of maturation of the thoracic legs during metamorphic development. Several unusual aspects of neurogenesis reported here distinguish these crustaceans from other arthropods. Lobsters apparently lack a postembryonic period of proliferation in the thoracic neuromeres despite the metamorphic remodeling that takes place in the larval stages. In contrast, an increase in mitotic activity towards the end of embryonic development is found in crabs, and neuroblast proliferation persists throughout the process of hatching into the larval stages. In both E20% lobster embryos and mid-embryonic crabs, expression of engrailed was found in a corresponding set of neurons and putative glial cells at the posterior neuromere border, suggesting that these cells have acquired similar specific identities and might, therefore, be homologous. None of the BrdU-labeled neuroblasts (typically 6-8 per hemineuromere over a long period of embryogenesis) was positive for engrailed at this and subsequent stages. Our findings are discussed in relation to the spatial and temporal patterns of neurogenesis in insects.

scholarly journals Oviposition behavior and host records for the parasitic midge Trichochilus lacteipennis (Johannsen) (Chironomidae: Orthocladiinae)

2018 ◽  
pp. 37-42
Author(s):  
David Harley Funk ◽  
Sherman Roberts ◽  
Alan Graham
Keyword(s):  
Larval Development ◽  
Adult Female ◽  
Water Surface ◽  
Oviposition Behavior ◽  
Long Strings ◽  
Larval Life ◽  
Free Living ◽  
Elliptio Complanata ◽  
Mussel Species

Adult female Trichochilus lacteipennis were observed to extrude long strings of eggs (up to 15 cm) in flight over a lake in Maine, USA. Once extruded females dropped to the water surface and released the strings. Larvae of T. lacteipennis are parasitic on Elliptio complanata at this site and probably additional unionid mussel species elsewhere. Based on our dissections of parasitized mussels and previous reports, it appears T. lacteipennis spend all or nearly all of their larval life within their mussel host, with first instars initially free-living inside the mantle. At some point larvae enter the marsupium and complete larval development on a diet of mussel eggs and/or glochidia before pupating within the marsupium. 

scholarly journals Morphology of larval and first juvenile stages of the kangaroo shrimp Dugastella valentina (Crustacea, Decapoda, Caridea), a freshwater atyid with abbreviated development and parental care

Zootaxa ◽  
2011 ◽  
Vol 2867 (1) ◽  
pp. 43 ◽  
Author(s):  
ANTONIO RODRÍGUEZ ◽  
JOSÉ A. CUESTA
Keyword(s):  
Parental Care ◽  
Larval Development ◽  
Free Living ◽  
Larval Stages ◽  
Incubation Chamber ◽  
Juvenile Stages

The larval development of Dugastella valentina consists of two zoeal stages and a decapodid. Larval stages are not free living; the complete larval development takes place in the female’s incubation chamber. The two zoeae, the decapodid and first postlarval stages still have a large amount of yolk, which ensures their nutritional independence (lecithotrophic stages) while staying within the maternal incubation chamber and the first days after release. The first juvenile is the first free living stage. In the present study the morphology of all larval stages as well as the first juvenile are described and illustrated, and comparison with known larval stages of atyids is made.

Studies on the behaviour, and development in fish, ofSubtriquetra subtriquetra: a uniquely free-living pentastomid larva from a crocodilian

Parasitology ◽  
1986 ◽  
Vol 93 (1) ◽  
pp. 81-98 ◽  
Author(s):  
Judith M. Winch ◽  
J. Riley
Keyword(s):  
Intermediate Host ◽  
Larval Development ◽  
Host Location ◽  
Stereotyped Behaviour ◽  
Infective Stage ◽  
Swim Bladder ◽  
Free Living ◽  
Larval Stages ◽  
Nasal Passages ◽  
Host Invasion

SUMMARYThe primary larva of the porocephalid pentastomidSubtriquetra subtriquetra, which infects the nasopharynx ofCaiman sclerops, is uniquely free-living. Eggs hatch within the nasal passages and the emergent larvae can remain infective to the fish intermediate host for 4–5 days. During this period larvae exhibit very stereotyped behaviour, alternating between a characteristic stationary ‘fishing’ posture and very brief periods of movement. Larval activity increases significantly at 3 days, probably effecting dispersal to a more favourable site for host invasion. Host location is passive and invading larvae penetrate to the swim-bladder where subsequent larval development, which involves 7 moults, occurs. All 8 larval stages are freely mobile in the swim-bladder and possess hooks. Sensilla, disposed in characteristic patterns, are present throughout development, increasing in number to the infective stage; the majority of sensilla are located on sensory papillae.

The missing links: larval and post-larval development of the ascoglossan opisthobranch Elysia viridis

2000 ◽  
Vol 80 (6) ◽  
pp. 1087-1094 ◽  
Author(s):  
Cynthia D. Trowbridge
Keyword(s):  
Larval Development ◽  
Growth Rates ◽  
Shell Length ◽  
Larval Growth ◽  
Model Organism ◽  
Larval Life ◽  
Codium Fragile ◽  
Planktotrophic Larvae ◽  
Algal Diet ◽  
Better Than

The stenophagous ascoglossan (=sacoglossan) opisthobranch Elysia viridis has long been a model organism for the study of endosymbiosis or kleptoplasty as well as one of the few herbivores to consume the introduced green macroalga Codium fragile on European shores. Larval and post-larval dynamics of the ascoglossan were investigated. Planktotrophic larvae of E. viridis grew at 5–10 μm d−1 (shell length) at 15°C on a unicellular algal diet (the cryptophyte Rhodomonas baltica); larvae became competent one month post-hatching. Effective feeding and chloroplast acquisition typically started within 2–3 d of metamorphosis. Slugs grew about 8 mm in the first month of post-larval life. During this period, juveniles held in the light did not grow faster or survive better than conspecifics held in the dark; thus, functional kleptoplasty did not occur during first three weeks of benthic life. While larval growth rates and the nature of metamorphic cues are consistent with those of many other opisthobranch species with planktotrophic larvae, measures of post-larval growth—particularly as it pertains to kleptoplasty—is a new contribution to opisthobranch biology.

The Beauty and the Beast: Aspects of the Autonomic Nervous System

Physiology ◽  
2000 ◽  
Vol 15 (3) ◽  
pp. 125-129 ◽  
Author(s):  
Roberto Corti ◽  
Christian Binggeli ◽  
Isabella Sudano ◽  
Lukas E. Spieker ◽  
René R. Wenzel ◽  
...  
Keyword(s):  
Heart Failure ◽  
Congestive Heart Failure ◽  
Nervous System ◽  
Sympathetic Nerve Activity ◽  
Vasoactive Drugs ◽  
Nerve Activity ◽  
Beauty And The Beast ◽  
Coronary Syndromes ◽  
Sympathetic Nervous ◽  
Selection Of

Sympathetic nerve activity is altered and is a prognostic factor for many cardiovascular diseases such as hypertension, coronary syndromes, and congestive heart failure. Therefore, the selection of vasoactive drugs for the treatment of these diseases should also take into consideration their effects on the sympathetic nervous system.

The Development and Growth of Ciona

1947 ◽  
Vol 26 (4) ◽  
pp. 616-625 ◽  
Author(s):  
N. J. Berrill
Keyword(s):  
Nervous System ◽  
Digestive System ◽  
Ciona Intestinalis ◽  
Growth Cycle ◽  
General Interest ◽  
Botryllus Schlosseri ◽  
Developmental Studies ◽  
Larval Stages ◽  
Artificial Fertilization ◽  
Sexually Mature

Ciona intestinalis (L.) is probably the most cosmopolitan species of ascidians and has long been of general interest. The adult morphology has been well described in monographic form by Roule (1884), the physiology of the heart and circulation by Heine (1902), Enriques (1904) and Wolf (1932), of the nervous system by Magnus (1902), Hecht (1918, 1926), Cate (1928), Haffner (1933), and Bacq & Florkin (1935), and of the digestive system by Yonge (1925). Developmental studies include that of the early embryology by Conklin (1905), problems of fertilization by Morgan (1945) and Damas (1899,1900). In no work, however, has there been a presentation of the entire Ciona organism from the tadpole stage through the critical post-larval stages to the young cionid ascidian. The present account portrays this period of development, together with a discussion of some significant but relatively obscure aspects of adult structure.Eggs and theRearing ofCiona intestinalisWhile ascidians in general are difficult to rear to maturity under laboratory conditions, Ciona is relatively easy, and together with Botryllus schlosseri (Pallas) and Diplosoma gelatinosum (M.-Edw.) is liable to appear more or less spontaneously in large aquaria into which tadpoles may have been brought. Artificial fertilization is readily accomplished, and at almost any time of the year, since Ciona is sexually mature above a certain size and reproduction is seasonal only to the extent of the rhythm of the growth cycle. Normally eggs are set free spontaneously at dawn, although individuals kept in the laboratory may accumulate eggs and the oviduct become swollen.

Development of Camallanus adamsi Bashirullah, 1974 (Nematoda: Camallanidae) in cyclopoid copepods

1976 ◽  
Vol 54 (12) ◽  
pp. 2055-2060 ◽  
Author(s):  
A. K. M. Bashirullah ◽  
Benazir Ahmed
Keyword(s):  
Larval Development ◽  
Intermediate Hosts ◽  
Larval Stages ◽  
Mesocyclops Leuckarti

The larval development of Camallanus adamsi Bashirullah, 1974 was followed in intermediate hosts, Mesocyclops leuckarti (Claus) and Thermocyclops crassus (Fischer), which were kept at 24 °C and 27 °C (average). The nematode molted twice in the haemocoel of copepods. The first molt occurred 117 h after infection at 24 °C and the second molt after 249 h. At 27 °C, the first and the second molts occurred 72 and 168 h respectively after the infection. Three larval stages are described.

Drosophila EcR-B ecdysone receptor isoforms are required for larval molting and for neuron remodeling during metamorphosis

Development ◽  
1998 ◽  
Vol 125 (11) ◽  
pp. 2053-2062 ◽  
Author(s):  
M. Schubiger ◽  
A.A. Wade ◽  
G.E. Carney ◽  
J.W. Truman ◽  
M. Bender
Keyword(s):  
Nervous System ◽  
Wide Spectrum ◽  
Control Cell ◽  
P Element ◽  
Ecdysone Receptor ◽  
Larval Stages ◽  
Receptor Isoforms ◽  
Imprecise Excision ◽  
Cell Type Specific ◽  
Insect Central Nervous System

During the metamorphic reorganization of the insect central nervous system, the steroid hormone 20-hydroxyecdysone induces a wide spectrum of cellular responses including neuronal proliferation, maturation, cell death and the remodeling of larval neurons into their adult forms. In Drosophila, expression of specific ecdysone receptor (EcR) isoforms has been correlated with particular responses, suggesting that different EcR isoforms may govern distinct steroid-induced responses in these cells. We have used imprecise excision of a P element to create EcR deletion mutants that remove the EcR-B promoter and therefore should lack EcR-B1 and EcR-B2 expression but retain EcR-A expression. Most of these EcR-B mutant animals show defects in larval molting, arresting at the boundaries between the three larval stages, while a smaller percentage of EcR-B mutants survive into the early stages of metamorphosis. Remodeling of larval neurons at metamorphosis begins with the pruning back of larval-specific dendrites and occurs as these cells are expressing high levels of EcR-B1 and little EcR-A. This pruning response is blocked in the EcR-B mutants despite the fact that adult-specific neurons, which normally express only EcR-A, can progress in their development. These observations support the hypothesis that different EcR isoforms control cell-type-specific responses during remodeling of the nervous system at metamorphosis.

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