• International Journal of Industrial Entomology and Biomaterials
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• v.11 no.2
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• pp.139-143
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• 2005

The implications of temperature (25, 30 and $35^{\circ}C$) and relative humidity (RH; 60, 70 and $80\%$) on the hatching rhythmicity and hatching parameters (percentage and duration) were studied in the silkworm, Bombyx mori L. under natural photoperiod (LD 12 : 12). Disease free layings (DFLs) of two pure silkworm breeds, Pure Mysore (PM, a multivoltine breed) and $NB_4D_2$ (a bivoltine breed), and their hybrid, $PM{\times}NB_4D_2$ were introduced into the experimental conditions on the $3^{rd}$ day of oviposition till completion of hatching. The hatching rhythm was predominantly diurnal under all temperature and humidity conditions, with peaks just after 'lights-on' phase (6 hrs). Extreme temperature and humidity conditions did not alter the hatching rhythmicity, but prolonged the hatching durations, extending it to the next day, coupled with reduced hatching percentage in PM and $PM{\times}NB_4D_2{\cdot}In\;NB_4D_2$, on the other hand, hatching did not extend to the next day. Hatching percentage in this breed, however, reduced below the economic level under high temperature and low humidity conditions. The high temperature and low humidity together, though did not alter the rhythmicity, seems to exert synergetic effect on the hatching percentage and its duration in the silkworm, B. mori.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.4
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• pp.486-491
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• 2020

This study was investigated the survival and hatching rate of fertilized eggs in olive flounder Paralichthys olivaceus at water temperature, salinity, duration of transport and different stock densities during commercial transport. The observed optimal temperature during transport was 17.5℃ similar to the natural environmental conditions. The proper salinity was observed to be at 33 psu (practical salinity unit) in both surviving and hatching rate. In terms of the duration of transport, there were no differences until 12 hours between survival and hatching rate, but shorter time of transport would be better. With the best conditions during transport, 20,000 eggs/L were handled in both survival and hatching rate. These results can be essential in the production and transport of healthy olive flounder seeds.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.05a
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• pp.272-274
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• 2003

A few studies have examined the hatching response of copepod diapause eggs to various factors (Ban and Minoda, 1991; Chen and Marcus, 1997). Marcus (1979) monitored the hatching of diapause eggs of Labidocera aestiva and suggested that diapause eggs of marine copepods undergo a refractory phase similar to other diapausing organisms. (omitted)

• Korean Journal of Environment and Ecology
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• v.38 no.2
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• pp.143-147
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• 2024

This study aimed to determine the egg-hatching period of boreal digging frogs, Kaloula borealis, and investigate whether the incubation temperature affects the hatching period. In this study, the egg hatching was recorded based on the appearance of the tadpole. The results of this study showed that all the eggs hatched within 48 hours after spawning, with 28.1% (±10.8, n=52) hatching within 24 hours and 99.9% (±0.23, n=49) within 48 hours after spawning. The mean hatching rate of tadpoles showed significant differences depending on the difference in water temperature. The mean hatching rate between 15 and 24 hours after spawning was higher at a water temperature of 21.1 (±0.2) ℃ than at 24.1 (±0.2) ℃. The results suggest rapid hatching occurs at relatively low water temperatures because the spawning habits that spawn eggs in temporary ponds or puddles in the rainy season require rapid hatching before the puddles dry out. The results of this study are helpful for understanding the most suitable temperature conditions for the incubation of eggs of the endangered species, boreal digging frog.

• Development and Reproduction
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• v.21 no.1
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• pp.79-91
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• 2017

The aim of this study was to compare the efficacy of cryopreservation methods for ex situ conservation of spermatozoa from far eastern catfish, Silurus asotus. The spermatozoa activity index (SAI) and hatching rates were higher in spermatozoa stored in Alserver's solution than those of spermatozoa stored in glucose solution. The SAI and hatching rates in all experimental groups gradually decreased with increasing duration of storage. Additionally, the SAI and hatching rates gradually decreased with increasing thawing temperatures at all storage durations (P<0.05). Based on the SAI and hatching rates, our results suggest that the optimal cryopreservation conditions of catfish spermatozoa involve storage in Alserver's solution with 15% ethylene glycol, and thawing at $25^{\circ}C$. Cryopreservation of spermatozoa is a useful and reliable technique for conserving gene resources and for artificial propagation of far eastern catfish.

• International Journal of Industrial Entomology and Biomaterials
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• v.14 no.2
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• pp.113-119
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• 2007

Tropical tasar silkmoth Antheraea mylilta D. is an economically important insect. The wild nature and above all unsynchronized emergence of moths lead to impairment in reproductive activity. The mating in moths is low (64%-70%), leaving about 30-36% of potential females unused for seed (= egg) production. Delay in mating adversely affects the reproductive performance such as mating behaviour, fecundity and fertility. Females are more severely affected by mating delay than males. Therefore, a study was under taken to develop a method to overcome the problem so that the production of layings can be increased to meet the ever increasing demand. It was revealed from the study that out of 16 possible age combinations (from the age groups of day 0 to day 3), female and male of day 0 (4-8 hours old) excel in their reproductive performance than others (with 94.4% mating success, 284 fecundity and 91.5% hatching). Reproductive performance declined significantly even if one of the parents was older. When either of the mating pair was 1 day old, the mating declined by 28%; fecundity by 32.8%; and hatching by 40.8%. The insemination of eupyrene sperm was declined by 35.2% when both the parents are 1 day old. Mating duration of 8 hours resulted in insemination of $8.3{\times}10^5$ eupyrene sperms, which was declined by 31.6%, 48% and 55% upon lowering of mating duration to 6 hr, 4 hr and 2 hr were maintained respectively.

• Journal of Forest and Environmental Science
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• v.28 no.4
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• pp.289-294
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• 2012

This study was conducted from April 2012 to June 2012 to analyze breeding status of Black woodpeckers (Dryocopus martius) in the Gayasan National Park. Nest height, tree diameter which a nest built and altitude at the nest site of Black woodpeckers were 17.4 m, 63.8 cm and 587 m, respectively. A pair of Black woodpeckers completed a clutch in 4 eggs on 7 May and 3 of eggs hatched on 24 May 2012. Both female and male incubated eggs and never left eggs without one of parents. A male more contributed to build a nest than a female. Incubation duration was higher in a male than in a female. Nestlings made a begging call in a nest during the growing period. Begging frequency of nestlings increased from 11 days up to 20 days after hatching. After then, nestlings reduced begging and fledged a nest 24 days after hatching. This study provided information of breeding ecology to protect and manage population of Black woodpeckers which are endangered species in South Korea.

• International Journal of Industrial Entomology and Biomaterials
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• v.13 no.2
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• pp.103-108
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• 2006

Efficacy of aqueous leaf extracts of medicinal plants viz., Eucalyptus globulus, Ocimum sanctum and Piper betle were evaluated against the hatching of eggs, mortality of nymphs and mortality and fecundity of adult mealy bugs (Maconellicoccus hirsutus Green) under in vitro conditions. Totally seven concentrations 1, 5, 10, 20, 50, 70 and 100 percent were tested against mealy bugs. The results revealed that with the increase in the concentration of extracts, there was a corresponding decrease in hatching, nymphal & adult mortality and fecundity in all the extracts tested. The hatching of eggs was minimum at 100 percent concentration in E. globulus (20.00%) followed by O. sanctum (30.42%) and P. betle (36.06%) over control (96.73%). The growth and development of nymphs and adults were adversely affected after the treatment. The nymphs did not attain the adult stage and there was total mortality of nymphs in different treatments. The duration of nymphal stage was reduced by 2-10 days in E. globulus, 1-7 days in O. sanctum and 1-2days P. betle at higher concentrations. However, at lower concentrations it was prolonged by 2-4 days in all the three extracts. At lower concentrations the mortality of adults was on par with the control. Similarly the adult duration was also reduced by 3-4 days at 100 percent concentration and prolonged by 5-6 days at lower concentrations in all the extracts. With the increase in concentrations of the extracts there was decrease in the fecundity of eggs. Thus, the leaf extracts of E. globulus was found to be most effective followed by O. sanctum and P. betle against mealy bugs.

• Fisheries and Aquatic Sciences
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• v.16 no.1
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• pp.25-34
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• 2013

Early ontogenic development in Siberian sturgeon Acipenser baerii was documented and the effects of different temperatures on embryonic and prelarval development were examined. Photograph-assisted data on morphogenesis in Siberian sturgeon prolarvae agreed well with published descriptions of their ontogeny and ecological behaviors, although certain aspects of differentiation, such as gill covering and scute development, could be rearing condition-sensitive. The present study provides the first characterization of the transient development of teeth during early larval stages; the pattern was congruent with the transition of prolarvae to exogenous feeding. From examinations of embryonic and prelarval development under different temperature conditions ($12-24^{\circ}C$), developmental speed was inversely related with temperature. Overall, hatchability was higher and hatching events were more synchronized at $20^{\circ}C$ than at lower temperatures. After hatching, similar patterns of temperature-dependency were observed in yolk sac absorption and the evacuation of the pigment plug. Our results suggest that the incubation of Siberian sturgeon embryos and prolarvae at temperatures close to $20^{\circ}C$ would be advantageous in hatcheries, based on reductions in the duration and uniformity of egg and prolarval developmental stages.

• The Korean Journal of Ecology
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• v.19 no.6
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• pp.575-582
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• 1996

Molipteryx fuliginosa (Uhler, 1860) is a plant juice sucker which feeds on new tips of Rubus oldhami Miquel and Zelkowa serrata Makino, and it has a strong preference for teses two plants in Korea. M. fuliginosa has one generation a year and hibernates as a young adult. Most of the winter survivors emerge in early May. It is the first time their host plants were found and reported. Females mainly lay their eggs one by one separately on the leaves of R. oldhami, and even on the steel wire, the lid guaze and the ground in the laboratory. Nymphs do not gather, but stay on the hatching site, Nymphs except the non-feeding first instar feed on young shoots. From the second to the fifth instar nymphs migrate to the upper part of the shoot and congregate in part on an expanded leaf. The new adults first appeared on 11 August, and remained in the host plant, and fed on until mid October. The duration of the hatching and molting, and the survivorship curve based on the laboratory rearing were determined.