• Korean journal of applied entomology
• /
• v.38 no.3
• /
• pp.217-224
• /
• 1999

This study was conducted to determine the larval development of tobacco cutworm, Spdodoptera litura Fabricius, reared on leaves of different leguminous plants of 11 varieties or cultivars, and to measure amount of leaves fed by the larva. Larval duration ranged from 11.5 to 15.7 days depending on different food with the shortest on geomjeongkong-1 and the longest on daek-wangddangkong. Among 6 larval development stages, the 1st instar stages was the longest(3.2~5.0 days) while the 4th instar was the shortest (1.0~1.5 days). In general, amount of leaves consumed was increased with larval age, and consumed from 5 to 74% of total food only during the last instar stage. And female consumed more food than male. While, larval mortality and the sex-ratio seem to have no relation with the amount of food per species.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.45 no.6
• /
• pp.716-722
• /
• 2012

The larval occurrence of the red snow crab Chionoecetes japonicus was investigated near Dokdo in the East Sea of Korea, and the larval timing of the genus Chionoecetes in world oceans was reviewed. C. japonicus larvae were collected seasonally at 12 stations in February, May, August, and November in 2011. A Bongo net with a 303 mesh was deployed with a double oblique tow. Larvae appeared from February to August, but no larvae were found in November. Zoea I occurred at nine stations with a few zoea II in February, and were found until August. The larval densities in February were high near the northern. In May, megalopa were found at eight stations with a few zoea II. No larvae were caught in November. The larval abundance in the research area peaked in February. Overall, the larval duration of the genus Chionoecetes in the world's oceans persisted for a long time, and Chionoecetes larvae occurred during the warm season in each area. The cold temperature at the sea bottom, where gravid females are found, may prolong larval production along the distribution range of the genus Chionoecetes.

• Development and Reproduction
• /
• v.17 no.4
• /
• pp.337-343
• /
• 2013

Post-thawed larval rearing in Pacific oyster Crassostrea gigas was performed to investigate the survival rate with time course in three kinds of larvae cryopreserved. The highest survival rate and larval activity index (LAI) of post-thawed larvae were obtained from the permeation in 0.2 M sucrose and 2.0 M ethylene glycol (EG) at $-1^{\circ}C/min$ in freezing speed showing the survival rates just after thawing of 63.8% in trochophore, 84.1% in D-shaped veliger and 56.3% in early umbo veliger. In post-thawed larval rearing with food supply, the larvae lasted their lives until 24 hours in trochophore, 75 hours in D-shaped veliger and 57 hours in early umbo veliger. The results suggested that each larval stage post-thawed revealed no more further development to subsequent respective stage.

• The Korean Journal of Zoology
• /
• v.37 no.3
• /
• pp.331-342
• /
• 1994

The larval development of Parupilumnus trispinosus Sakai, 1965 completed in the laboratory consisted of four zoeal stages and one megalopal stage. Completion of the lanral development required at least 18 days at 20-25"C. The morphology of the lanrae of each stage is described in detail, and comparisons are made with larvae of other 11 species of the subfamily Pilumninae. Although, the zoeae of the subfamily Pilumninae show almost consistent characteristics of the mouthpart appendages, in the characteristics of the carapace spines and the abdominal lateral knobs they can be divided into five groups: (1) the genera Heteropanope and Heteropilumnus, (2) the genera Actumnus and Pilumnus, (3) Pilumnopeus makiona and P sewutifrons, (4) Porupilumnus trispinosus, and (5) Pilumnopeus eucratoides and. p indic${\alpha}$.

• Animal cells and systems
• /
• v.3 no.1
• /
• pp.59-68
• /
• 1999

Chthamalus challengeri Hoek was collected from intertidal rocks to rear the larvae from hatching through nauplius to cyprid in the laboratory. Larval development consists of six nauplius stages and a cyprid. Unilobed labrum with a prominent protuberance and the frontolateral horns folded under the anterior cephalic shield margin are diagnostic features through all nauplius stages. The posterior border of the cephalic shield bears no posterior shield spines in nauplius stages IV-Ⅵ. There is a specific hispid seta in the fourth group of the antennal endopodite. Morphological features such as the cephalic shield, labrum, abdominal process, antennules, antennae and mandibles in all nauplius and cyprid stages are illustrated and described. The numerical setations of the antennule are found to aid in the intraspecific identification of barnacle nauplius stages without dissection. The keys to each stage of the barnacle larvae in Korean coastal waters are provided based on the reared nauplii of seven species: Pollicipes mitella Octomeris sulcata, Chthamalus challengeri, Balanus albicostatus B. trigonus, B. amphitrite, and B. improvisus inhabiting Korean coastal waters.

• Parasites, Hosts and Diseases
• /
• v.50 no.1
• /
• pp.83-87
• /
• 2012

To determine the effects of kimchi extracts at different temperatures on larval development, $Ascaris$ $suum$ eggs were mixed with soluble part of 7 different brands of commercially available kimchi and preserved at either $5^{\circ}C$ or $25^{\circ}C$ for up to 60 days. $A.$ $suum$ eggs incubated at $25^{\circ}C$ showed marked differences in larval development between kimchi extract and control group. While all eggs in the control group completed embryonation by day 21, only 30% of the eggs in the kimchi extract group became embryonated by day 36 and about 25% never became larvated even at day 60. At $5^{\circ}C$, however, none of the eggs showed larval development regardless of the incubation period or type of mixture group. To determine the survival rate of $A.$ $suum$ eggs that showed no embryonation after being preserved at $5^{\circ}C$, eggs preserved in kimchi extracts for 14, 28, and 60 at $5^{\circ}C$ were re-incubated at $25^{\circ}C$ for 3 weeks in distilled water. While all eggs in the control group became larvated, eggs in the kimchi extract group showed differences in their embryonation rates by the incubation period; 87.4 % and 41.7% of the eggs became embryonated after being refrigerated for 14 days and 28 days, respectively. When refrigerated for 60 days, however, no eggs mixed in kimchi extract showed larval development. Our results indicate that embryogenesis of $A.$ $suum$ eggs in kimchi extract was affected by duration of refrigeration, and that all eggs stopped larval development completely in kimchi kept at $5^{\circ}C$ for up to 60 days.

• Korean journal of applied entomology
• /
• v.49 no.4
• /
• pp.351-355
• /
• 2010

This study was conducted to determine the relationship of larval density of tobacco cutworm, Spodoptera litura (Fabricius) to damage in greenhouse sweet pepper. Laboratory experiments, cage experiments by artificial release and field investigation were carried out in 2008. The leaf consumption rate increased greatly with larval development. The damaged leaves had several round or oval shape holes on the surface or lost certain parts of them, and the fruit damaged had a conspicuous hole on the surface or scar marks around the calyx. In the field investigation, fruit damage was highly correlated with larval densities and reached 3.5% damage at maximum. Cage experiments showed that numbers of non-marketable fruit increased as increasing larval densities released. The larval density at two weeks before harvest had a high relationship with the percentage of damaged-fruit at harvest. Corresponding larval density caused 1, 3, 5% of damaged-fruit was 0.2, 0.5, 0.8 larvae per plant, respectively.

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

• Korean journal of applied entomology
• /
• v.25 no.4 s.69
• /
• pp.215-220
• /
• 1986

Glucose, trehalose, and glycogen content were measured in haemolymph and the body during larval development of the oriental corn borer, Ostrinia furnacalis ($Guen\'{e}e$). Glucose content varied in haemolymph, but in the body it gradually decreased at all larval stages. As the larva proceeds growth, the initial high level of trehalose increased further in haemolymph whereas the low level trehalose gradually decreased in the body. Glycogen levels in haemolymph rose gradually during larval growth whereas those in the body increased sharply at the two latter instar larval stages. It is apparent that the existence of a homeostasis in carbohydrate levels between haemolymph ana the body.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.32 no.2
• /
• pp.69-79
• /
• 2016

Distillers dried grain (DDG) and makgeolli spent grain (MSG) are agricultural byproducts to produce alcoholic beverage. However, they are known to contain enough nutrients. Mealworm is a promising insect resource for an animal feed ingredient as well as alternative human food. With low cost, DDG and MSG were investigated as a feed ingredient for rearing high quality mealworms. DDG and MSG were mixed with wheat bran and compared to control feed (only wheat bran) for its effects on larval survivorship, larval weight, duration for developmental period, pupation rate, and pupal weight. When DDG added, larval survivorship was reduced to 50~70% compared to the control group. Larvae fed on DDG were heavier from third to sixth week. Especially, larvae with 50% DDG were 28% heavier than the control group at the third week. For the larval period, the 50% DDG group was 11% less than that for the control. The pupal weight for the 30% DDG group was 7% heavier than that for the control group. Pupation rates for all the DDG groups were higher than 90%. When compared to the control, larval survivorship for the 70% MSG group was low, but the 50% and 70% MSG groups were high during the seventh and eighth weeks because of delayed development. After the eighth week, larvae with 70% MSG showed the highest larval weight increase as 9~18% compared to the control group. Except 70% MSG group, all of MSG groups showed more than 90% pupation rates. We confirmed that adding 30~50% of DDG or MSG to conventional wheat bran have a strong potential to replace the conventional wheat bran insect feed for quality insect production.