• Animal cells and systems
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• v.14 no.4
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• pp.333-341
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• 2010

The larvae of Scyra acutifrons are described and illustrated for the first time. The larval stage consists of two zoeal and a megalopal stages. The zoea of S. acutifrons is compared with those of other known species of the Epialtidae from the northern Pacific. The zoea of Scyra acutifrons can be easily distinguished from that of S. compressipes by having a longer rostral carapace spine and an endopod of maxillule with three setae. It is found that the genus Scyra (Pisinae) shows a great similarity to Pisoides bidentatus (Pisinae) and the genus Pugettia (Epialtinae) in the family Epialtidae; especially, S. acutidens coincides well with two Pugettia species (Pugettia incisa and P. gracilis) in the characteristics of the zoeal mouthpart appendages. To facilitate the study of plankton-collected material, a provisional key to the known zoeae of the Epialtidae from the northern Pacific is provided.

• Korean Journal of Environmental Biology
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• v.36 no.2
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• pp.232-240
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• 2018

This study was performed to investigate the effects of water temperature and salinity on the egg development and larval attachment of Ascidiella aspersa. The egg development and larval attachment were examined in 12 different water temperatures (6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26 and $28^{\circ}C$) and two salinity conditions(30 and 34 psu). The hatching and developmental rates of A. aspersa showed a tendency to increase with increasing water temperature regardless of salinity and to decrease after the optimal water temperature range. The optimal water temperatures for the hatching and development of egg of A. aspersa were in the range of $20-22^{\circ}C$. The low threshold water temperature was not different between 1.5 and $1.8^{\circ}C$ at 30 and 34 psu, respectively. The attachment rate showed the optimal water temperature range of $16-22^{\circ}C$ irrespective of the salinity and the attachment time increased continuously with increasing water temperature. Experimental results showed that optimum development and survival temperature of the egg and larvae of A. aspersa were in the range of $20-22^{\circ}C$ regardless of the salinity conditions. The results can be used to predict the distribution and occurrence of A. aspersa, and to prevent economic damages caused by its spread.

• Korean journal of applied entomology
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• v.60 no.4
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• pp.449-462
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• 2021

We analyzed the effects of temperature on the survival, development, and reproduction of the non-diapause Asian corn borer, Ostrinia furnacalis (Lepidoptera: Crambidae). A 16:8 h light:dark photoperiod was supplied to the non-diapause stages of O. furnacalis. The insects were raised on an artificial diet at seven constant temperatures between 15 and 35℃ for immature stages, and eight temperatures between 13 and 33℃ for the adult stage. The survival rate of eggs exceeded 70% at all temperatures, whereas survival of larvae was as low as 7.4% at 15℃. The developmental periods of the immature stages decreased with increasing temperature, but the larval period did not decrease further at 35℃. The pupal weight increased with increasing temperature, but the female weight decreased at 35℃. Variations with different last larval instars within the colonies at different temperatures were observed. Adults produced offspring at all tested temperatures. Adult longevity and the pre-oviposition and oviposition periods decreased with increasing temperature, but the pre-oviposition period increased at 33℃. Total fecundity exceeded 400 viable eggs at 22℃ and 31℃. The mean daily fecundity during the oviposition period and the mean daily fecundity on the day of oviposition increased with increasing temperature, but decreased at 33℃. Daily fecundity sharply increased at earlier adult ages and slowly decreased thereafter. The simulated oviposition frequency was greatest at 22℃. The lower developmental threshold temperatures were estimated to be the lowest at 9.7℃ for the first instar larva and the highest at 14.7℃ for the 5th to last instar larval stage, using a linear model.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.145-145
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• 2003

To evaluate the effect of PAHs on fertilization and larval development of the Pacific oyster, Crassostrea gigas via in vivo exposure for 30 days. Conditioned C. gigas adult brood stock was taken from oyster farm in May 2003 and raised in flow through tank at 20-22$^{\circ}C$ with feeding equivalently mixed marine microalgae: Chaetoceros simplex, C. gracilis, Isochrysis galbana and Tetrasemis tetrathele. The oysters were exposed to PAHs cocktail at 200ppb (10 species) until they are fully riped with an untreated group. Motility of sperm, Fertilization and The percent of D-shaped larvae was measured under microscope (Olympus BX-50). Fertilization capability using dry sperm and eggs from both non- and PAHs treated brood stocks was significantly reduced at the treated group (P<0.01). In addition to the origin effect, it was obvious that fertilization of eggs from both group were adversely suppressed in consistent with PAHs level (P<0.01). The percent of D-shaped larvae in treated group was significantly reduced comparing to non-treated. The percent was adversely correlated with PAHs level, which was more significantly reduced in treated group. Therefore, it was obvious that PAHs exposure on the Pacific oyster has adverse affects on the sperm as well as larvae in both maternal and acute source.

• Journal of Sericultural and Entomological Science
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• v.37 no.2
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• pp.235-243
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• 1995

Recently, the cocoon production is reducing very steeply in Japan. The main reason for this cocoon reduction is due to high labor cost and the production expense is apt to rise year by year. Accordingly, the improvement of cocoon productivity by retrenchment of the production expense is intensively required in my country. Therefore, the silkworm rearing on the artificial diet is largely expected as the innovation techniques of sericulture. Since rearing of the silkworm on artificial diets has first been achieved in 1960, and the silkworm larvae were reared throughout all the instars on artificial diets(Fukuda et al., 1960, Ito & Tanaka, 1960). The artificial diets used at this time contained 50% or more of dried, pulverized mulberyy leaves as one of the main ingredients, and the composition was rather simple. When reared on these diets, larval growth and development were retarded, small cocoons appeared, and the adults laid only a small number of eggs. At first, we would like to study about nutritional requirement of the silkworm, using the chemically defined diet which prepared artificially. Subsequently, attempts were made to improve the diets by replacement of crude ingredients with possibly purer compounds, as mentioned later. Before giving the details on individual nutrient, I would like to summarize about the outline of utilization flow of various nutrients through the larval-pupal development and these daily quantitative requirements per body weight in the silkworm when they were reared on mulberry leaves.

• International Journal of Industrial Entomology and Biomaterials
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• v.17 no.2
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• pp.173-180
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• 2008

The influence of temperature and relative humidity in infection and cross-infection of Nosema bombycis and N. mylitta respectively in mulberry silkworm, Bombyx mori L. on larval mortality, multiplication of pathogens, larval weight and growth rate in three different seasons were studied. Seasons were selected in such condition, when very less fluctuations between minimum and maximum temperature and minimum and maximum relative humidity ($25{\sim}28^{\circ}C$ and $65{\sim}72%$ R.H) was observed i.e., season-1. Fluctuations between minimum and maximum temperature were less ($28.05{\sim}34.50^{\circ}C$) but R.H % was more ($55{\sim}81%$) in season-2. Fluctuations between minimum and maximum temperature and R.H % were more ($20.00{\sim}40.5^{\circ}C$ and $64.00{\sim}90.00%$) in season-3. Growth rate of microsporidian-infected silkworm is directly related to the prevailing temperature and relative humidity in silkworm. Silkworm can tolerate slight variation of temperature but slight variation of relative humidity disfavours the development of silkworm and favours the multiplication of pathogens.

• Journal of Aquaculture
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• v.12 no.3
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• pp.229-236
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• 1999

in the present study, the zinc toxicity to larval development and seed attachment of the abalone, Haliotis discus hannai was obtained under continuous flow through system. The zinc concentration melted from zinc coating pipe for 7 months ranged from $89.00\pm2.55 \mu\textrm{g}/\ell to 15.23\pm2.58\mu\textrm{g}/\ell(Y=0.85M^2-19.71+109.96)$. Treatments were carried out with zinc concentration $0~160 \mu\textrm{g}/\ell$. The maximum and minimum of fertilization rate were $87.7\pm5.3%$ in control, $83.7\pm7.6%$ in zinc concentration $160\mu\textrm{g}/\ell$, respectively. The maximum and minimum of hatching rate were $87.5\pm4.5%$ in zinc concentration $10\mu\textrm{g}/\ell$, $79.3\pm5.6%$ in zinc concentration $160\mu\textrm{g}/\ell$, respectively. Both of the results were not significantly different (P>0.05). But the normality rate, setting rate and survival rate of abalone larvae at over zinc concentration TEX>$20\mu\textrm{g}/\ell$ decreased rapidly and showed significantly different from those of the other group(P<0.05).

• Animal Systematics, Evolution and Diversity
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• v.12 no.2
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• pp.91-99
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• 1996

The complete larval development of Philyra pisum De Hann, 1841 from hatching to the megalopal stage was obtained by culture in the laboratory. Two zoeal and one megalopal stages are described and illustrated . The frist zoea of the present species is very similar to those of other two Philyra species except for the reduced carapace spines. The first zoeae belonging to the subfamily Philyrinae can be divided into two groups based on the zoeal characteristics: the first group is composed of Arcania septemspinosa, A. undecimspinosa elongata, and Myra fugax, whereas the second group is composed of Philyra corallicola, P. syndactyla, and P. pisum.

• Journal of the Korean Society of Tobacco Science
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• v.20 no.1
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• pp.33-39
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• 1998

Survival, growth and reproduction of the cigarette beetle, Lasiodema sewicome F., were studied on flue-cured (NC82), air-cured (Br.21), aromatic (Izmir) tobacco and artificial diet (wheat feed 95% + yeast 5%). Cigarette beetle adults occurred from first generation in the flue-cured and aromatic tobacco, but no adults emerged in air-cured tobacco after the 2nd generations. The head capsule widths of larvae of the cigarette beetles L sewicome F.1 reared on different diets at 2$0^{\circ}C$, $25^{\circ}C$ and 3$0^{\circ}C$ were measured. The head capsule development was slower at 2$0^{\circ}C$ on the same diets than $25^{\circ}C$ and 3$0^{\circ}C$, and slower in the flue-cured and aromatic tobacco than the artificial diet at 2$0^{\circ}C$ and 2S$^{\circ}C$, At $25^{\circ}C$ the larval head capsule developed more rapidly in the aromatic tobacco than the flue-cured tobacco. However, no larval head development was noticed in the air-cured tobacco. The correlation between population densities of cigarette beetle,1 sewicome F., and sugar content of tobacco leaves was positive, but negative in nicotine contents. The regression between densities and sugar content was Y : 22.79 X + 57.29 (r=0.891**), and between nicotine content was Y : -141.31X + 321.40(r=-0.917**).

• Journal of Sericultural and Entomological Science
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• v.41 no.2
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• pp.82-86
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• 1999

Hemolymph proteins and vitellogenin from mulberry longicorn beetle, Apriona germari HOPE, were indentified, and their changed were analyzed during the larval-pupal-adult development and in the newly laid eggs. Thres major hemolymph proteins were observed in the hemolymph during the larval-pupal-adult development and the intensity of their proteins was clearly observed during the pupal stage. From SDS-[olyacrylamide gel electrophoresis analysis, molecular weights of three major hemolymph proteins were approximately 74 kDa, 78kDa and 85kDa. Vitellogenin in A. Germati appeared in the hemolymph of only abult female and is considered to be a product synthersized within 10 days after adult emergence. The molecular weight of vitellogenin was consited of a heavy subunit (165 kDa) and a light subunit (40 kDa).