• International Journal of Industrial Entomology and Biomaterials
• /
• v.26 no.1
• /
• pp.61-66
• /
• 2013

Baculum elongatum has several peculiarities such as parthenogenesis, unique external features, changing body color, and dropping oviposition, which makes it a potential economically useful insect. Oviposition was performed by females without fertilization by the sperm of males. The oviposition period was $42.2{\pm}22.7$ days and the number of eggs per female was $109.5{\pm}70.5$ eggs. The hatch rate was 73.3% at $25^{\circ}C$ and 66.7% after low temperature treatment ($8^{\circ}C$ for 60 days). In nature, B. elongatum overwinters as an egg, but it can be assumed from the results that cold temperatures were not required for hatching. The hatch rate was 98.2% in the treatment using floral foam, fermented sawdust, and leaves. The developmental period was $100.9{\pm}4.2$ days for eggs, $55.3{\pm}4.6$ days for nymphs, and $49.7{\pm}16.0$ days for adults. The length of the eggs was $0.33{\pm}0.0$ cm and the lengths of the nymphs were clearly distinguishable according to the instar stage. Clover(Trifolium repens) was an excellent diet as it was similar to the host plant and could be used as an alternative diet. The rate of reaching adulthood for the insects was 66.7% on an artificial diet containing 25% acacia leaves. For sustainable mass rearing of nymphs or adults of B. elongatum, a natural diet could be used such as acacia (Robinia pseudoacacia), white oak (Quercus aliena), chestnut (Castanea crenata var. dulcis), and bush clover (Lespedeza bicolor), or an alternative diet such as clover or artificial diet.

• Journal of Korean Society of Forest Science
• /
• v.95 no.2
• /
• pp.174-176
• /
• 2006

The experiments were conducted by supplying hosts with natural food(chestnut, peach, Quince). The developmental difference of peach pyralid moth, Dichocrocis punctiferalis was examined in the laboratory under three different natural food regime. The periods of egg, larva and pupa were $6.01{\pm}0.07$, $12.23{\pm}0.03$ and $13.32{\pm}0.01$ days on the chestnut fruit, $6.21{\pm}0.01$, $18.69{\pm}0.02$ and $13.38{\pm}0.03$ days on the peach fruit and $7.02{\pm}0.04$, $22.62{\pm}0.04$ and $13.44{\pm}0.14$ days on the quince fruit, respectively. The growth of D. punctiferalis larva was better chestnut fruit than other tested fruits. The rates(%) of hatching, pupation and emergence were 94.0, 57.0 and 63.3 on the chestnut fruit, 89.2, 77.8 and 85.7 on the peach fruit and 79.6, 52.6 and 70.7 on the quince fruit, respectively. The survival rate(%) of D. punctiferalis from hatching to emergence were 31.0 on the chestnut fruit, 4.8 on the peach fruit and 14.3 on the quince fruit, respectively. The sex ratio (female: male) of all pupae obtained on the tested natural food fruits were 52.7 : 47.3. The sex ratio of D. punctiferalis reared on three difference food fruits were no significantly. It can be used a as the basic research for the study of D. punctiferalis.

• Journal of Aquaculture
• /
• v.8 no.3
• /
• pp.241-249
• /
• 1995

Sperm from mud loach (Misgurnus mizolepis) were electroporated in the presence of plasmid DNA, pRSV/luc or pMT/hGH over a range of field strength of 0-1,625 V/cm with capacitance from 0 to 1,000 ${\mu}F$, and the effects of electroporation on fertilization, hatching, early survival, and efficiency of gene transfer were investigated. Average fertilization rate, hatching rate and early survival rate up to yolk sac absorption of all experimental groups were not significuntly different (P>0.05). The proportion of fish carrying pRSV/luc based on the polymerase chain reaction (PCR) analysis was ranged from 0 to $20\%$, however, the values of gene transfer efficiency from the different eledctroporation conditions were not significantly different. PCR analysis of pMT/hGH transferred groups revealed that screening of pMT/hGH transferred fish by PCR was difficult because of significant nonspecific amplifications resulted from the homologous sequences in the genome of mud loach.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.44 no.5
• /
• pp.516-523
• /
• 2011

To compare four populations of sea squirt Halocynthia roretzi adults, their egg quality and larval development were investigated in the hatchery. The populations were: south sea wild (SSW), south sea cultured (SSC), east sea wild (ESW) and Iwate Japan cultured (IJC). Egg quality and larval development were compared using 13 factors (fertilization rate and diameter, proximate composition, amino acid and fatty acid contents of eggs, hatching rate and various sizes of tadpole larvae) which were obtained from each population. Fertilized egg diameter, hatching rate and size of tadpole larvae were significantly different among the four populations (P<0.05). Eggs were produced with higher crude protein ($5.20{\pm}0.00%$ SSW, $4.71{\pm}0.01%$ ESW, $4.66{\pm}0.01%$ SSC and $3.96{\pm}0.01%$ IJC) and lipid ($1.22{\pm}0.01%$ ESW, $1.01{\pm}0.00%$ SSW, $0.77{\pm}0.01%$ SSC and $0.69{\pm}0.00%$ IJC,) contents from domestic wild populations than from Japanese or cultured populations. Also amino acid and fatty acid contents were different. The extent of similarity between domestic and Japanese populations (30.5% IJC:SSW, 34.3% IJC:SSC and 40.7% IJC:ESW) was relatively low but was very high between SSW and SSC (73.9%). These results may have been due to differences in the abundance of food types and environmental conditions in the four localities and consequent differences in the diets of the sea squirts.

• Development and Reproduction
• /
• v.15 no.1
• /
• pp.17-24
• /
• 2011

Lipid metabolites involved in cellular regulation as signaling mediators. Prostaglandins (PGs), metabolites of lipid are involved to pregnancy at the time of implantation but the functional roles of PGs on embryo development are still controversy and largely unknown. In previous report, the levels of $PGE_2$ and $PGF_{2a}$ at embryos of morula stage and blastocyst stage were explored (Cheon et al., 1998). In this study, the previous suggestion was confirmed and the possible downstream mediator of prostaglandin $E_2$ and prostaglandin $F_{2a}$ on the expansion and hatching of mouse embryo was examined. As expected, developmental rate of the blastocyst to expanded stage was a concentration-response curve that showed the highest expansion rate at 10 ${\mu}M$ $PGE_2$, but at 100 ${\mu}M$ $PGE_2$, the rate was decreased. In contrast to the $PGE_2$, $PGF_{2a}$ stimulated expansion without toxicity at highest concentration. Cotreatment of PGs with indomethacin overcame the inhibitory effects of indomethacin in expansion. Exogenous PGs also improved the development of expanded embryos to the hatching stage. Besides, PGs receptors' transcripts detected at blastocyst. $PGE_2$ was caused of calcium fluctuation in the blastocyst but $PGF_{2a}$ did not. The changes of intracellular calcium concentration were different between indomethacin pretreated embryos and non-treated embryos. Based on these results it is suggested that PGs work as paracrine and/or autocrine factors through calcium and the others which were not identified in this study.

• Fisheries and Aquatic Sciences
• /
• v.16 no.4
• /
• pp.253-260
• /
• 2013

We investigated the toxicological effects of Aroclor 1254 on the fertilized eggs, embryos and larvae of the olive flounder Paralichthys olivaceus. The survival rate and hatching success of the embryos decreased significantly in treated groups in an Aroclor 1254-dose-dependent manner. Significant differences were found at ${\geq}5{\mu}g/L$ Aroclor 1254 compared to the control group. Hatching success occurred at ${{\leq}}10{\mu}g/L$ Aroclor 1254, which was not significantly different to the control. Embryo malformation increased significantly at ${\geq}1{\mu}g/L$, and included yolk-sac and tail-flexure abnormalities. There was a significant decrease in the survival rate of the larvae at ${\geq}5{\mu}g/L$, which was accompanied by the malformations described above. Notably, concentrations as low as $1{\mu}g/L$ caused a significant increase in abnormalities in the larvae, including incidences of multi-focal hemorrhages, pericardial and yolk-sac edema, inhibition of swim bladder inflation and severe developmental delay. The responses to Aroclor 1254-induced toxicity were generally similar among fertilized eggs, embryos and larvae from three separate flounder hatcheries: Cheju Island, Yeosu and Chungnam, South Korea. These results indicate the high acute toxicity of Arolcor 1254 concentrations of which as low as $1{\mu}g/L$ in olive flounder larvae can affect unhatched embryos. To conclude, the average $LC_{50}$ values for Aroclor 1254 in the embryos and larvae were 50.92 and $3.08{\mu}g/L$, respectively. Additionally, the average $EC_{50}$ values, based on the rate of damage were 14.72 and 5.6$1{\mu}g/L$, respectively.

• Journal of Marine Life Science
• /
• v.4 no.2
• /
• pp.63-69
• /
• 2019

This study aims to investigate how ovulation induction of red spotted grouper, Epinephelus akaara varies when treated with different hormonal substances such as ovaprim, pimozide, LHRHa, and HCG. As for LHRHa, we injected it at four different concentrations: 50 ㎍kg^-1, 100 ㎍kg^-1, 150 ㎍kg^-1, and 200 ㎍kg^-1. All hormonal substances including LHRHa were injected into the back muscles. Buoyant, embryonic survival, fertilization, and hatching rate were the highest in LHRHa and LHRHa + pimozide group. When LHRHa was injected at different concentrations, buoyancy and fertilization rate were the highest in 100 ㎍kg^-1 group. Embryonic survival and hatching rate were the highest in 150 ㎍kg^-1. Based on these experimental results, we concluded that LHRHa at the concentration of 100 ㎍kg^-1 is the most efficient for the ovulation induction in this fish species.

• Korean Journal of Environmental Biology
• /
• v.27 no.3
• /
• pp.292-296
• /
• 2009

This study was conducted to estimate relationship between temperature and egg development of Nannophya pygmaea, an endangerd dragonfly species in Korea, using eight different temperature conditions (17, 20, 22, 25, 28, 30, 33, and $36^{\circ}C$). Eggs of N. pygmaea were collected from female adults inhabited a small wetland in Mungyeong-si, Gyeongsangbuk-do, Korea, in June 2007. As a result, hatching rates were 2.86, 17.09, 24.32, 39.67, 34.43, 40.57, 44.79, and 1.75% at 17, 20, 22, 25, 28, 30, 33, and $36^{\circ}C$, respectively. The nonlinear model of the temperature related to egg development was well fit to the modified Sharpe and DeMichele model. The derived lower developmental threshold temperature for egg hatching was $14.02^{\circ}C$(y=0.005988x-0.084, $r^2$=0.99), and the derived optimal development temperature was $30{\sim}35^{\circ}C$.

• Journal of Aquaculture
• /
• v.10 no.3
• /
• pp.357-362
• /
• 1997

In order to obtain the basic information for seedling production of flatfish, Limanda herzensteini, the influence of water temperature and salinity on egg development was investigated. The desirable water temperature for egg hatching was9~$15^\circC$. The time of egg development was shorter with higher water temperature. The relationships between the water temperature (T:$^\circC$) and the required time (t:hour) from egg to each development stage were given as follows ; 8-cell : 1/t=0.0284T-0.0554 (r=0.9999) Morula : 1/t=0.0137T-0.0527 (r=0.9998) Kupffer's vesicle : 1/t=0.0035T-0.0133 (r=0.9762) Hatching : 1/t=0.0012T-0.0007 (r=0.9981) Biological mimimum temperature for the egg development was estimated to the be $2.6^\circC$ in average. The salinity which showed over 50% survival rate from fertilized egg to hatching was 35~$38\textperthousand$.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.51 no.4
• /
• pp.420-425
• /
• 2018

We characterized egg development and investigated the effects of temperature on embryonic development time, in the convict cichlid Amatitlania nigrofasciata. Fertilized eggs of this species have an ovoid shape (horizontal axis, $1.56{\pm}0.02mm$; vertical axis, $1.26{\pm}0.04mm$) and smooth translucent chorion surrounded by a layer of mucous secretion. At $27{\pm}0.5^{\circ}C$, the first cleavage, blastula, gastrula and 16-somite stages of A. nigrofasciata eggs began at 1.5, 4.83, 14 and 40 hours after fertilization, respectively. We measured the development rate of embryos at $12-33^{\circ}C$ and found that the time period from fertilization to hatching was 94 hours at $24^{\circ}C$, 64 hours at $27^{\circ}C$ and 50 hours at $30^{\circ}C$. At temperatures of $12-21^{\circ}C$, all fertilized eggs died before hatching and those incubated at $33^{\circ}C$ died immediately after hatching.