Larval and Early Post-Larval Development of Arctica Islandica

1982 ◽  
Vol 62 (4) ◽  
pp. 745-769 ◽  
Author(s):  
R. A. Lutz ◽  
R. Mann ◽  
J. G. Goodsell ◽  
M. Castagna
Keyword(s):  
Larval Development ◽  
Growth Rates ◽  
Larval Growth ◽  
Ammonium Hydroxide ◽  
Culture Conditions ◽  
Dilute Solution ◽  
Arctica Islandica ◽  
Larval Stages ◽  
Experimental Laboratory ◽  
Rearing Techniques

Mature eggs were stripped from ripe adult specimens of Arctica islandica and exposed to a dilute solution of ammonium hydroxide for various lengths of time before addition of stripped sperm. Larval and early post-larval stages were cultured under experimental laboratory conditions using standard bivalve rearing techniques. Larval cultures were maintained at various controlled temperatures ranging from 8·5 to 14·5 °C. Minimum time to settlement was 32 days at a temperature of approximately 13 °C; at temperatures between 8·5 and 10·0 °C, settlement was not observed until approximately 55 days after fertilization. Larval growth rates were significantly faster at temperatures between 11·0 and 145 °C than at temperatures between 8°C. Morphometry of the larval shell and morphology of the larval hinge apparatus were independent of larval growth rates and experimental culture conditions.

Larval and Early Post-Larval Development of Arctica Islandica

1982 ◽  
Vol 62 (4) ◽  
pp. 745-769 ◽  
Author(s):  
R. A. Lutz ◽  
R. Mann ◽  
J. G. Goodsell ◽  
M. Castagna
Keyword(s):  
Larval Development ◽  
Growth Rates ◽  
Larval Growth ◽  
Ammonium Hydroxide ◽  
Culture Conditions ◽  
Dilute Solution ◽  
Arctica Islandica ◽  
Larval Stages ◽  
Experimental Laboratory ◽  
Rearing Techniques

Mature eggs were stripped from ripe adult specimens of Arctica islandica and exposed to a dilute solution of ammonium hydroxide for various lengths of time before addition of stripped sperm. Larval and early post-larval stages were cultured under experimental laboratory conditions using standard bivalve rearing techniques. Larval cultures were maintained at various controlled temperatures ranging from 8·5 to 14·5 °C. Minimum time to settlement was 32 days at a temperature of approximately 13 °C; at temperatures between 8·5 and 10·0 °C, settlement was not observed until approximately 55 days after fertilization. Larval growth rates were significantly faster at temperatures between 11·0 and 145 °C than at temperatures between 8°C. Morphometry of the larval shell and morphology of the larval hinge apparatus were independent of larval growth rates and experimental culture conditions.

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.

Embryonic and larval development of the caridean shrimp Palaemon argentinus (Decapoda, Caridea): effects of salinity and diet

Crustaceana ◽  
2021 ◽  
Vol 94 (1) ◽  
pp. 45-62
Author(s):  
Carolina Tropea ◽  
Liane Stumpf ◽  
Laura S. López Greco
Keyword(s):  
Larval Development ◽  
Artemia Salina ◽  
Culture Conditions ◽  
Nutritional Requirements ◽  
Larval Performance ◽  
Larval Rearing ◽  
Caridean Shrimp ◽  
Natural Habitats ◽  
Larval Stages ◽  
Wide Range

Abstract The caridean shrimp Palaemon argentinus is a species of commercial and ecological interest. Its numerous larval stages, the lack of knowledge on their nutritional requirements, and their ability to survive in a wide range of salinities raise questions on the optimum conditions for larval rearing in captivity. The present study was aimed at evaluating embryonic development under different salinities and larval development under different combinations of salinities and diet regimes, in order to define alternative, cheaper culture conditions. We tested salinities usually encountered by the species in natural habitats (0.1, 1 and 5 ppt) and a highly protein-inert diet (Tetracolor®) as a potential replacement for live food (nauplii of Artemia salina). The incubation period and fecundity were similar among salinity treatments. Overall, the number of survival days and percentage of zoeae that moulted two, three and four times were higher when embryogenesis occurred at 5 ppt and when larvae were exposed to 5 ppt. These results suggest that the conditions experienced by embryos affect the performance of the first larval stages, and probably reflect the lower energetic requirements of zoeae to osmoregulate as water and haemolymph osmolarity become closer. On the other hand, larval performance was better when fed A. salina nauplii than Tetracolor®. The latter may not cover the nutritional requirements of zoeae or may have low digestibility due to insufficient enzymes in the undeveloped larval digestive system. Based on the present results, we conclude that a salinity of 5 ppt combined with a diet consisting of Artemia sp. nauplii is optimal for larval culture at early stages.

Growth dynamics in natural populations of Sphaeriidae clams (Sphaerium, Musculium, Pisidium)

1979 ◽  
Vol 57 (2) ◽  
pp. 441-456 ◽  
Author(s):  
G. L. Mackie
Keyword(s):  
Growth Rates ◽  
Larval Growth ◽  
Natural Populations ◽  
Growth Dynamics ◽  
Logarithmic Phase ◽  
River Population ◽  
Small Litter ◽  
Larval Stages ◽  
Permanent Pond ◽  
Accelerated Growth

Analyses of life history samples of five species of sphaeriid clams collected at least monthly for 1 year from 10 different habitats show that growth of all larval stages stops when parents cease to grow. During the logarithmic phase of growth larvae grow slower than parents in temporary and permanent pond populations of Musculium lacustre, Pisidium casertanum, and Pisidium variabile, as fast as parents in a river population of Sphaerium fabale, and as fast or faster than parents in five populations of Musculium securis. Species with slow larval growth rates are usually semelparous and univoltine but can be iteroparous by precocious birth of larvae and multivoltine by accelerated growth of semelparous individuals. Species with rapid larval growth rates are usually iteroparous because larvae grow faster than parents and (or) there is precocious birth of larvae. There is greater mortality of larvae during early stages than during later stages of larval development. The greatest numbers of larvae per parent usually occur in early winter and (or) late spring; winter and summer 'kills' often result in small litter sizes.

scholarly journals Short and long term consequences of larval stage exposure to constantly and ephemerally elevated carbon dioxide for marine bivalve populations

2012 ◽  
Vol 9 (11) ◽  
pp. 15901-15936
Author(s):  
C. J. Gobler ◽  
S. C. Talmage
Keyword(s):  
Larval Development ◽  
Larval Stage ◽  
Growth Rates ◽  
Larval Growth ◽  
Marine Bivalve ◽  
High Co2 ◽  
Legacy Effect ◽  
Bivalve Larvae ◽  
Co2 Concentrations

Abstract. While larval bivalves are highly sensitive to ocean acidification, the basis for this sensitivity and the longer term implications of this sensitivity are unclear. Experiments were performed to assess the short term (days) and long term (months) consequences of larval stage exposure to varying CO2 concentrations for calcifying bivalves. Higher CO2 concentrations depressed both calcification rates assessed using 45Ca uptake and RNA:DNA ratios in Mercenaria mercenaria and Argopecten irradians larvae with RNA:DNA ratios being highly correlated with larval growth rates r2 > 0.9). These findings suggested that high CO2 has a cascading negative physiological impact on bivalve larvae stemming in part from lower calcification rates. Exposure to elevated CO2 during the first four days of larval development significantly depressed A. irradians larval survival rates, while a 10 day exposure later in larval development did not, demonstrating the extreme CO2-sensitivity of bivalve larvae during first days of development. Short- (weeks) and long-term (10 month) experiments revealed that individuals surviving exposure to high CO2 during larval development grew faster when exposed to normal CO2 as juveniles compared to individuals reared under ambient CO2 as larvae. These increased growth rates could not, however, overcome size differences established during larval development, as size deficits of individuals exposed to even moderate levels of CO2 as larvae were evident even after 10 months of growth under normal CO2 concentrations. This `legacy effect' emphasizes the central role larval stage CO2 exposure can play in shaping the success of modern day bivalve populations.

Dissolved Oxygen Requirements for Embryonic and Larval Development of the Hardshell Clam, Mercenaria mercenaria

1971 ◽  
Vol 28 (3) ◽  
pp. 379-381 ◽  
Author(s):  
George Morrison
Keyword(s):  
Dissolved Oxygen ◽  
Larval Development ◽  
Growth Rates ◽  
Larval Growth ◽  
Mercenaria Mercenaria ◽  
Percent Mortality ◽  
Time Periods ◽  
Oxygen Requirements ◽  
Eggs And Larvae ◽  
Embryonic And Larval Development

Eggs and larvae of Mercenaria mercenaria were exposed to various levels of dissolved oxygen for varying time periods. Larval growth was normal in levels of dissolved oxygen at or above 4.2 mg/liter, but was essentially curtailed in levels at or below 2.4 mg/liter. Larvae survived extended exposures of 1 mg/liter, but showed little growth. Growth rates of larvae transferred to conditions of high dissolved oxygen after various periods of exposure to low dissolved oxygen became normal. Eggs developed normally at oxygen levels down to 0.5 mg/liter. One hundred percent mortality was experienced at 0.2 mg/liter.

scholarly journals Embryonic development and larval stages of Steindachneridion parahybae (Siluriformes: Pimelodidae): implications for the conservation and rearing of this endangered Neotropical species

2012 ◽  
Vol 10 (2) ◽  
pp. 313-327 ◽  
Author(s):  
Renato M. Honji ◽  
Carlos E. Tolussi ◽  
Paulo H. Mello ◽  
Danilo Caneppele ◽  
Renata G. Moreira
Keyword(s):  
Larval Development ◽  
Average Length ◽  
Larval Growth ◽  
Average Diameter ◽  
Larval Phase ◽  
Larval Stages ◽  
Neotropical Species ◽  
First Feeding ◽  
In Captivity ◽  
Optic Vesicles

Steindachneridion parahybae is a freshwater catfish endemic to the Paraíba do Sul River and is classified as an endangered Neotropical species. An increasing number of conservation biologists are incorporating morphological and physiological research data to help conservation managers in rescue these endangered species. This study investigated the embryonic and larval development of S. parahybae in captivity, with emphasis in major events during the ontogeny of S. parahybae. Broodstocks were artificially induced to reproduce, and the extrusion occurred 200-255 degree-hours after hormonal induction at 24°C. Larval ontogeny was evaluated every 10 minutes under microscopic/stereomicroscopic using fresh eggs samples. The main embryogenic development stages were identified: zygote, cleavage, including the morula, blastula, gastrula phase, organogenesis, and hatching. The extruded oocytes showed an average diameter of 1.10 ± 0.10 mm, and after fertilization and hydration of eggs, the average diameter of eggs increased to about 1.90 ± 0.60 mm, characterized by a large perivitelline space that persisted up to embryo development, the double chorion, and the poles (animal and vegetative). Cell division started about 2 minutes after fertilization (AF), resulting in 2, 4, 8 (4 x 2 arrangement of cells), 16 (4 x 4), 32 (4 x 8) and 64 (2 x 4 x 8) cells. Furthermore, the blastula and gastrula stages followed after these cells divisions. The closed blastopore occurred at 11 h 20 min AF; following the development, the organogenetic stages were identified and subdivided respectively in: early segmentation phase and late segmentation phase. In the early segmentation phase, there was the establishment of the embryonic axis, and it was possible to distinguish between the cephalic and caudal regions; somites, and the optic vesicles developed about 20 h AF. Total hatching occurred at 54 h AF, and the larvae average length was 4.30 ± 0.70 mm. Gradual yolk sac reduction was observed during the first two days of larval development. The first feeding occurred at the end of the second day. During the larval phase, cannibalism, heterogeneous larval growth and photophobia were also observed. This information will be important in improving the artificial reproduction protocols of S. parahybae in controlled breeding programs.

scholarly journals Short- and long-term consequences of larval stage exposure to constantly and ephemerally elevated carbon dioxide for marine bivalve populations

2013 ◽  
Vol 10 (4) ◽  
pp. 2241-2253 ◽  
Author(s):  
C. J. Gobler ◽  
S. C. Talmage
Keyword(s):  
Larval Development ◽  
Larval Stage ◽  
Growth Rates ◽  
Larval Growth ◽  
Marine Bivalve ◽  
High Co2 ◽  
Legacy Effect ◽  
Bivalve Larvae ◽  
Co2 Concentrations

Abstract. While larval bivalves are highly sensitive to ocean acidification, the basis for this sensitivity and the longer-term implications of this sensitivity are unclear. Experiments were performed to assess the short-term (days) and long-term (months) consequences of larval stage exposure to varying CO2 concentrations for calcifying bivalves. Higher CO2 concentrations depressed both calcification rates assessed using 45Ca uptake and RNA : DNA ratios in Mercenaria mercenaria and Argopecten irradians larvae with RNA : DNA ratios being highly correlated with larval growth rates (r2>0.9). These findings suggested that high CO2 has a cascading negative physiological impact on bivalve larvae stemming in part from lower calcification rates. Exposure to elevated CO2 during the first four days of larval development significantly depressed A. irradians larval survival rates, while a 10-day exposure later in larval development did not, demonstrating the extreme CO2 sensitivity of bivalve larvae during first days of development. Short- (weeks) and long-term (10 month) experiments revealed that individuals surviving exposure to high CO2 during larval development grew faster when exposed to normal CO2 as juveniles compared to individuals reared under ambient CO2 as larvae. These increased growth rates could not, however, overcome size differences established during larval development, as size deficits of individuals exposed to even moderate levels of CO2 as larvae were evident even after 10 months of growth under normal CO2 concentrations. This "legacy effect" emphasizes the central role larval stage CO2 exposure can play in shaping the success of modern-day bivalve populations.

scholarly journals amontillado, the Drosophila Homolog of the Prohormone Processing Protease PC2, Is Required During Embryogenesis and Early Larval Development

Genetics ◽  
2003 ◽  
Vol 163 (1) ◽  
pp. 227-237 ◽  
Author(s):  
Lowell Y M Rayburn ◽  
Holly C Gooding ◽  
Semil P Choksi ◽  
Dhea Maloney ◽  
Ambrose R Kidd ◽  
...  
Keyword(s):  
Larval Development ◽  
Secretory Pathway ◽  
Larval Growth ◽  
Peptide Hormones ◽  
Complementation Group ◽  
Prohormone Processing ◽  
Complementation Groups ◽  
Regulated Secretory Pathway ◽  
Processing Protease ◽  
Larval Molt

Abstract Biosynthesis of most peptide hormones and neuropeptides requires proteolytic excision of the active peptide from inactive proprotein precursors, an activity carried out by subtilisin-like proprotein convertases (SPCs) in constitutive or regulated secretory pathways. The Drosophila amontillado (amon) gene encodes a homolog of the mammalian PC2 protein, an SPC that functions in the regulated secretory pathway in neuroendocrine tissues. We have identified amon mutants by isolating ethylmethanesulfonate (EMS)-induced lethal and visible mutations that define two complementation groups in the amon interval at 97D1 of the third chromosome. DNA sequencing identified the amon complementation group and the DNA sequence change for each of the nine amon alleles isolated. amon mutants display partial embryonic lethality, are defective in larval growth, and arrest during the first to second instar larval molt. Mutant larvae can be rescued by heat-shock-induced expression of the amon protein. Rescued larvae arrest at the subsequent larval molt, suggesting that amon is also required for the second to third instar larval molt. Our data indicate that the amon proprotein convertase is required during embryogenesis and larval development in Drosophila and support the hypothesis that AMON acts to proteolytically process peptide hormones that regulate hatching, larval growth, and larval ecdysis.

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.

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