• Journal of Sericultural and Entomological Science
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• v.39 no.2
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• pp.174-179
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• 1997

The larval head capsule width, larval weight and length of mulberry longicorn beetle, Apriona germari Hope were measured when the larvae were exuviated in artificial diet rearing. The larval head capsule width from the 1st to the 12th instar was ranged from 0.12 to 0.69 cm, and growth ratio of each instar was significantly high between the 1st and the 2nd instars. The fitness to Dyar's law for the larval head capsule width was 87.6%. When the logarithum of the larval head capsule width is plotted against the number of instars, the calculated regression line was LogY=0.12086+0.06998X and Dyar's constant was 1.18. The larval weight was increased with larval developmental stages, and the coefficient of variation of larval weight was apparently high. But the calculated regression line was LogY=-0.91592+0.25959X and Dyar's constant was 1.25. The growth ration of the larval length was clearly high between the 2nd and the 3rd instars, and that of larvae from the 4th instar was decreased. The calculated regression line was LogY=-0.16932+0.09841X and Dyar's constant was 1.25. In conclusion, our results suggested that the larvae growth of mulberry longicorn beetle appeared to be highly related in the larval head capsule width, larval weight and length.

• Korean Journal of Environmental Biology
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• v.39 no.4
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• pp.536-541
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• 2021

Pantala flavescens is a dominant Odonata species in the rice fields in Korea. To determine the effects of different temperatures on its larval growth and emergence, field and laboratory experiments were conducted. Larval growth was also monitored in mono-cropping and double-cropping rice fields. The growth of larvae was monitored every week by measuring the head width. In the field experiment, no difference was found in larval growth and emergence between the control temperature and +1.9℃ of the control temperature. The larval growth was greater at 23℃ than at 20℃ laboratory temperatures, and no emergence was recorded at either temperature after eight weeks of monitoring. There was a quadratic relationship between larval growth and temperature in an incubator at five temperature regimes of 15, 20, 25, 30, and 35℃. Midseason water drainage caused the extinction of the existing individuals and newly hatched larvae dominated after re-watering in the rice fields. Larval size was greater in double-cropping fields than in mono-cropping fields in late July but the tendency was reversed in early August. The results of this study suggest that temperature warming will directly promote the larval growth of P. flavescens and indirectly influence seasonal growth via changes in water management in rice fields.

• Development and Reproduction
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• v.16 no.2
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• pp.107-112
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• 2012

Early growth, the rate of yolk sac absorption, and nucleus size in liver parenchymal cells were correlated with the nutritional status of first feeding larval haddock, Melanogrammus aeglefinus. Larvae that successfully began exogenous feeding maintained high growth rates, delayed yolk sac resorption, and had larger hepatocyte nuclear sizes than starved larvae. At 10 days post hatch (DPH) the cumulative mortality in the starved larval haddock group was 100%. The area of the hepatocyte nuclei in starved larvae gradually decreased, reaching its lowest value by 9 DPH. Our results support the current practice of providing the first food supply at 3 DPH. Hepatocyte nuclear size can be used to assess larval haddock nutrition status, and may be a good criterion for assessing the success of transition from endogenous to exogenous feeding.

• Korean Journal of Environmental Biology
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• v.23 no.2 s.58
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• pp.114-119
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• 2005

Larval survivorships, growth rates, developmental rates, and emergence rates of Cloeon dipterum were studied under four constant temperatures $(10^{\circ}C,\; 15^{\circ}C,\;20^{\circ}C,\;and\;25^{\circ}C)$ in the laboratory. Larval mortalities were relatively higher during the initial one-week period, but those tend to be stabilized as the experiments proceed. Judging from the growth and develop-mental rates, estimated optimal temperature for larval growth and development lies between $20^{\circ}C\;and\;25^{\circ}C$. Estimated larval period for emergence is less than 100 days.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.5
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• pp.489-494
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• 2010

The nutritional demand of oyster larva (Crassostrea gigas) were investigated to determine the optimal culture conditions and improve micro-algae utilization. Changes in nutrients and shell growth were examined in fed and 96-h (48 h in late umbone stage) oysters at four larval stages. Shell growth increased significantly in D shape larvae, regardless of feeding variations. No growth was observed in starved larvae, except in shell length of umbone (to 11.9 ${\mu}m$). Fed larvae showed significant growth in all development stages (P < 0.05). During starvation, lipids were most significantly decreased in all larval stages (by 76.8%, 68.3%, 76.3%, and 40.3%, respectively), followed by protein (41.1%, 31.1%, 33.1%, 16.7%) and nitrogen-free extracts (40.8%, 24.3%, 36.9%, 20.1%), Gross energy (kcal/g) consumption in each larval stage was 49.6%, 35.1%, 39.1%, and 20.4%, respectively. Our results indicate that lipids are the most important energy source during the early larval development stages of C. gigas.

• The Korean Journal of Malacology
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• v.21 no.1
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• pp.65-70
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• 2005

The purpose of this study is to determine the appropriate substrate for larval settlement and spat growth in the purple clam, Saxidomus purpuratus in laboratory culture. Larvae were reared with 3 different types of sediments (mud, sand, and mixed) for 46 days in settlement experiment, and settled spats were further grown in 3 types of sediments for 36 weeks in growth experiment. The density of settled spats in muddy sediments was more than 2 times higher than those in mixed or sandy sediments. But, the average size of settled spats in muddy sediments was smaller than those in mixed or sandy sediments. After 36 weeks of growth period, growth rate decreased as shell length increased. When shell length was less than 2 mm, growth rate in mixed sediments was significantly higher than that in sandy sediments. When shell length was more than 2 mm, there was no significant difference in growth rate among different substrates. Sediment type affected growth rate only when the spats were relatively small (less than 2 mm). Muddy sediments seems better for larval settlement, while mixed sediments is best for spat growth. We suggest the laboratory procedure for enhancing seedling production of S. purpuratus.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.4
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• pp.378-383
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• 2001

Larvae of Metapenaeopsis dalei (Rathbun) were successfully spawned and reared in the laboratory under controlled conditions. The experiments were designed to examine effects of salinity (20, 25, 30 and 35), temperature (21, 24 and $27^{\circ}C$ ) and food (five items) on larval development, survival and growth, Salinity affected larval survival, from $\%$ at 20, to $60\%$ at 35 (protozoea 1 to first postlarva), The highest survival rate was obtained at $35\%_{\circ}$. Temperature affected larval survival, from $46\%$ at $27^{\circ}C$ to $54\%$ at $21^{\circ}C$(protozoea 1 to first postlarva). The highest survival rate was obtained at $24^{\circ}C$. Mortality was the highest from protozoea 1 to protozoea 3, but decreased considerably for all temperatures once the mysis stage was reached. Larval growth was affected by different of food items. Phytoplankton (Isochrysis galbana) was the optimum food for the larval survival and the growth from protozoea 3 to first postlarva.

• Journal of fish pathology
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• v.23 no.3
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• pp.303-311
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• 2010

Our previous finding summarizing that larval sieving process is inevitable but triggers the outbreak of scutica-like ciliates (SLCs) in the seed production of Patinopecten yessoensis urged further study to determine best suggestable sieving interval in an agreeable range of water quality. In the mass seed production of the scallop, SLC outbreak was closely related to the larval sieving in which larvae were drained on the basis of every 3-day (5T), 5-day (3T), 7-day (2T), or 9-day (1T) from culture tanks onto a mesh screen and placed back into new water in cleaned tanks. The larval performance of growth and survival was clearly dependent on the sieving intervals. It was in order of 3T, 5T, 2T, and 1T for both of growth and survival and in reverse order for SLC infection frequency, confirming that larval sieving is necessary but damageable if it overwhelms the larval resistance. Interestingly, the larval damages by the sieving persisted to their ensuing spat life in terms of nursery growth, survival, and abnormality.

• Journal of Aquaculture
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• v.20 no.3
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• pp.194-198
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• 2007

Reproductive traits of Palaemon gravieri such as embryo size, number of embryo (fecundity), incubation period, larval development mode, larval development period, larval survival and larval growth were described and compared to analyze the correlation among those traits. Embryo volume is a primary factor determining other ensuing reproductive features. Egg volume was $0.042mm^3$ in the first developmental stage. Embryo volume in P. gravieri was comparatively small which is indicative of great number of embryo (y = 3.0161x + 0.0185 $R^2$ = 0.74 positive isometric relationship) and relatively long incubation period. Larvae survived from zoea 1 to post-larvae and it took 45 days at $22^{\circ}C$. Survival rate of the larvae was rather great in the early stage and thereafter steadily decreased. Daily growth rate of larvae in P. gravieri at $22^{\circ}C$ was 0.0195 mm on average. They grew steadily as time went by. Incubation period was between 10-14 days at $22^{\circ}C$. Larval development mode was almost complete planktotrophic. PNR (point of no return) appeared to be the third day on average. Survival rate of larvae without feeding declined rapidly between 3 and 4 days. Larval development period and stage frequency were 23-30 days and 11 stages which imply prolonged larval period and high mortality. The pattern of brood production followed fast successive parturial pattern. Most ovigerous female had mature ovary when they performed parturial molt soon after hatching (larval release).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.807-812
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• 2013

The energy budget of the larvae of pandalid shrimp, Pandalopsis japonica, reared in the laboratory from zoea to post-larva was investigated. Energy used during the growth of the shrimp larvae was calculated daily for feeding, growth, molting, and metabolism. The total energy used was 16.2 J for the entire larval stage. Molting energy loss was estimated at a total 1.03 J. Energy used for respiration was estimated at a total of 1.85 J. The intake energy by feeding reached a total of 77.69 J. The total sum of energies used by excretion and egestion was 58.61 J. Larvae assimilated 24.57% of ingested food and used 84.91% for somatic growth. The gross growth efficiency ($K_1$) was 22.19% for the entire larval stage, and the net growth efficiency ($K_2$) was 90.31%. Maintenance costs were estimated at 9.69% of assimilated energy for the entire larval stage.