• 한국발생생물학회지:발생과생식
• /
• 제18권1호
• /
• pp.25-31
• /
• 2014

This study was investigated spawning behavior, structure of egg masses and egg development in Aplysia kurodai inhabiting the coastal waters of Jeju Island, Korea. The mating and courtship behavior of A. kurodai occurred in the form of unilateral copulating with chain formation. In chain copulation, only the first animal acted as a female; the second and succeeding animals acted as males (sperm donors) to the animals in front and as females to the animals behind. The fertilized eggs were packaged in capsules that are embedded in jelly to form a cylindrical string called an egg masses. The number of capsule per cm of the egg masses was 55 to 60 capsules and each capsule within the egg masses held 15 to 25 eggs. After spawning, the egg masses were bright yellow or orange in color. This egg masses color not changed until embryos developed into trochophore stage. Thereafter, as embryo developed from trochophore stage to veliger stage the egg masses color became brownish. The fertilized eggs were spherical, with a diameter of approximately $80{\pm}1{\mu}m$ at spawning. At 5 to 6 days after spawning, the embryo developed into trochophore stage and began to rotate within the egg capsule. In the trochophore stage, the precursor of the velum, called the prototroch or prevelum, developed. At 10 days after spawning, the prevelum is transformed into the velum, and the trochophore developed into veliger stage. Between 10 to 15 days after spawning, the veligers broke out of the egg capsule, and hatched as free-swimming larvae.

• 한국응용곤충학회지
• /
• 제25권1호
• /
• pp.37-40
• /
• 1986

필리핀에 있는 국제미작연구소(國際米作硏究所) 논 포장(圃場)에서 이앙(移秧)후 $15{\sim}20$일(日) 된 묘(苗)에서 Scirpophaga incertulas의 난(卵)을 1984년(年) 7월 부터 10월 까지 채집(採集)하여 난기생봉(卵寄生蜂)의 기생율(寄生率) 및 생태(生態)를 조사한 결과(結果)는 다음과 같다. ScirpoPhaga incertulas 의 난(卵)에서 나온 벌목 천적(天敵)으로 Tetrasticus schoenobii, Telenomus rowani, Trichogramma japonicum 3종(三種)이 발견(發見)되었고 기생봉(寄生蜂)의 생물적(生物的)인 습성(習性)에 기초(基礎)를 둔 기생율(寄生率) 계산(計算)방법을 소개하였다. 난기생봉(卵寄生蜂) 3종(三種)의 공기생(共寄生) 조합(組合)은 T. rowani+T. japonicum 조합(組合)이 가장 많았고 T. rowani 는 단기생성(單寄生性) 천적(天敵)으로 우화성충(羽化成蟲) 수(數)가 가장 많았지만 3종(三種)의 기생봉중(寄生蜂中) T. schoenobii 는 유충기간(幼蟲期間) 중 Scirpophaga incertulas 의 난(卵)을 $2{\sim}4$개(個) 소모(消耗)시키므로 가장 유용(有用)한 천적(天敵)이었으며 이 천적(天敵)의 1세대기간(世代期間)은 $10{\sim}14$일(日) 이었다.

• 한국해양학회지:바다
• /
• 제18권2호
• /
• pp.104-109
• /
• 2013

이번 연구에서는 서해와 남해에 서식하는 노래미(Hexagrammos agrammus)와 쥐노래미(Hexagrammos otakii)의 산란특성 연구를 위해 2012년 11월부터 12월까지 스쿠버다이빙을 통한 잠수조사를 실시하였다. 서해에서는 수심 6-7 m의 크고 작은 암반지역 위에 있는 홍조류에 노래미 난괴가 간격을 두고 부착되어 있었으며, 난괴 주변에도 홍조류가 많이 분포하고 있었다. 산란기의 노래미 수컷은 붉은색의 혼인색을 띄며 난괴를 보호하고 있었고, 수정란과 함께 은폐되어 눈에 잘 띄지 않았다. 남해의 경우 수심은 서해와 같은 6-7 m이지만, 사질 및 암반에 놓인 폐그물 위, 바위 틈, 해조가 무성한 암반지역 등 비교적 다양한 곳에 노출되어 있는 4-8개의 쥐노래미 난괴를 확인할 수 있었으며, 서해와는 다르게 외부에 노출되고 조류소통이 좋은 지역에서 난괴가 확인되었으며, 쥐노래미 수컷의 혼인색은 황금빛을 띄고 있어 쉽게 발견할 수 있었다.

• 한국응용곤충학회지
• /
• 제37권2호
• /
• pp.119-206
• /
• 1998

만수국 혼식과 만수국, 잔디, 산검양옻나무, 붉나무 및 양파 등의 식물체 추출액이 토마토에서 당근뿌리혹선충의 기생에 미치는 영향을 알아보기 위하셔 실험을 수행하였다. 만수국을 토마토와 혼식한 실험에서는 토마토 정식 15일전에 만수국을 이식한 구가 15일 후에 이식한 구보다 당근뿌리혹선충의 발생이 적었으며, 잎과 뿌리의 추출액 처리가 혼식보다 더욱 효과적이었다. 즉 만수국 잎추출액의 원액을 토마토 정식 5일전에 처리한 구의 난낭수는 2.2개, 뿌리추출액의 원액을 처리한 구는 5.6개로서 무처리구의 129.4개보다 현저히 적었다. 또한 잔디 추출액처리의 경우에도 무처리구의 난낭수가 87.2개였던데 비하여 원액 처리구는 21개, 2배 희석액 처리구에서는 28.4개로 적었다. 산검양옻나무, 붉나무 및 양파추출액도 당근뿌리혼선충의 발생을 현저히 억제시켰는데, 무처리구의 난낭수 193.6개에 비하여 산검양옻나무 추출액 원액 5일전 처리구에서는 1.6개, 붉은나무 추출액 원액 처리구는 1.6개, 양파추출액 원액 처리구는 6.2개로서 매우 효과가 있었다. 이 실험에서 사용하는 식물체의 추출액을 토마토 정식전에 처리하는 것이 동시 또는 후에 처리하는 것보다 효과적이었으며 추출액의 농도가 높을수록 형성된 난낭수가 적었다.

• 한국패류학회지
• /
• 제9권2호
• /
• pp.1-15
• /
• 1993

The reproductive ecology of the purple shell, Rapana venosa was investigated by the histological observations on depositions of the egg capsules, and hatching of larvae in the laboratory and the subtidal zone of the vicinity of piung-do, Chollabud-do, west coast of korea, for one year from June 1992 to May 1993. The results are summarized as follows:1. Rapana venosa is dioecious in sex. The ovary is composed of a number of ovarian lobules, and the testis comprises a number of ovarian lobules, and the testis comprises of gonads could be classified into 4 stages in males and 5 stages in females: 1) growing stage(in female subdivided into 2 stages of early and late growing stage). 2)mature stage. 3)spent stage or copulationstage. 4)rdcovering stage. The early growing stage in females of the purple shell was in September through February, late gorwing stage was in October to March, mature stage was in September to January, mature stage was in September to July, copulation stage was in Februaty to June and recovering stage in April to October.3. Spawning occurred 3-4 times at intervals of 1-3 days, and completed within 10 days from the beginning of spawning during the spawning season of the year.4. From the results of laboratory and field observations, egg masses are composed of a number of egg capsules, egg masses are occurred from May to late August, and in mid August depositions of egg mass in composed of 90-113 egg capsules, fecundity in an egg capsule was ranged 984 to 1,241 eggs(average 1,096 egg). Therefore, fecundity in total egg capsules spawned per individual during the spawning season is estimated as approximately 320,000 to 450,000 egges.5. The incubation period during deposition of an egg capsule to hatching larvad tood 17 days at 18.3-20.4%C(water temperature)and 1.021 (specific gravity fo sea water).

• 대한수의학회지
• /
• 제33권2호
• /
• pp.277-283
• /
• 1993

In the present study, observations were made on the life-history of Lymnaea viridis under laboratory conditions, involving incubation period of the eggs and their hatching rate, shell length of the newly hatched snails, sexual maturity, size of the snails when the snail produced the first egg-mass, the number of eggs in each egg-mass, egg-laying, ovipostion, growth rate of the snails, and longevity of the snail. At temperatures between $19.8^{\circ}C$ to $22.5^{\circ}C$, incubation period of the eggs occupied 10~12 days, and after beginning of hatching, all young snails emerged completely from the egg-mass within 5 days. The hatching rate was 88%. The average shell length of the newly hatched snails was about 0.064cm. The rate of growth was extraordinarily rapid under good laboratory conditions. When two snails were reared in one culture vessel($20{\times}15{\times}5cm$) with blue-green algae at about $22^{\circ}C$, snail growth was optimal, taking 37 days to reach 1.2cm in shell length. Sexual maturity reached in about 19 days. The size of the snails at sexual maturity was $0.78{\pm}0.05cm$ in length and $0.47{\pm}0.04cm$ in width. The first egg-masses produced were $0.59{\pm}0.22cm$ in length and $0.34{\pm}0.08cm$ in width, and contained 7~38 eggs. The eggs are usually laid in water. The egg-laying was affected by food and temperature. Snails fed with blue-green algae at about $22^{\circ}C$ produced larger egg-masses than the snails fed with fish food at about $26^{\circ}C$. Under conditions of continuous activity and growth, the maximum expectation of life appears to be 109~350(mean 230) days. And the shell length of snails at death were 1.39~1.64cm.

• Fisheries and Aquatic Sciences
• /
• 제18권4호
• /
• pp.395-399
• /
• 2015

We observed seasonality and other characteristics of spawning in the greenling Hexagrammos agrammus off the coast of Tongyeong. Eleven spawning grounds were identified between November, 2013 and January, 2014. The fertilized eggs of H. agrammus were assigned to developmental stages I, II, III, and IV. Based on this classification, we showed that the spawning season extended from the end of October to mid-January. H. agrammus used diverse seaweed species attached to shallow bedrock as spawning substrata that provided good camouflage. Two to seven egg masses were fertilized around the holdfasts of individual seaweeds at depths of 1.2-4.0 m. We identified species-specific reproductive traits of H. agrammus during the spawning season, including strong parental care of the fertilized eggs.

• The Plant Pathology Journal
• /
• 제17권3호
• /
• pp.159-163
• /
• 2001

Influence of soil temperature [accumulated degree-day for the base temperature $5^{\circ}$($\textrm{DD}_5$)] on the development of Meloidogyne arenaria were studied in a winter grown oriental melon greenhouse in Seongju, Korea. Egg masses were first observed on roots at the accumulation of 565 $\textrm{DD}_5$(40 days after transplanting), suggesting that the nematode has completed the first generation in 40 days. Second-stage juveniles (J2) densities were lowest at 863 $\textrm{DD}_5$ in April, first increased at 1,334 $\textrm{DD}_5$ in May, peaked at 2,951 $\textrm{DD}_5$ in July, and decliner thereafter. Development of egg masses and J2 density in soil revealed that M. arenaria could develop in 7-8 generations in a year in the greenhouse. Degree-day monitoring, therefore, could aid to predict nematode development in soil and can be valuable tool a to develop root-knot nematode control strategies.

• 농약과학회지
• /
• 제20권4호
• /
• pp.281-285
• /
• 2016

블루베리에서의 갈색날개매미충 산란특성과 산란량 감소를 위한 황색끈끈이 트랩의 효과를 조사하였다. 수관상부, 중부, 하부에서의 갈색날개매미충 난괴 발생율은 각각 56.6~60.2%, 23.8~28.1%, 11.7~19.7%로 반 이상이 상부에 집중 분포하였다. 난괴가 한 개만 발생한 가지비율이 50.9%로 가장 높았으며 난괴수가 2개인 가지비율은 20.5%로 다음으로 높았고, 3개와 4개 이상인 가지비율은 각각 14.6%, 14.0%였다. 황색끈끈이트랩을 1개월간 설치한 결과 갈색날개매미충 유살량은 트랩 당 평균 17.1마리였고, 주당 난괴수는 트랩처리구와 무처리구 각각 0.4, 1.3으로 황색끈끈이트랩을 설치 할 경우 무처리구에 비해 산란량이 1/3로 감소하였다. 즉 황색끈끈이트랩 설치로 갈색날개매미충 산란량을 줄일 수 있을 것으로 기대된다.

• 한국패류학회지
• /
• 제8권1호
• /
• pp.21-28
• /
• 1992

Field investigations were made in 1991 and 1992 in Kwangju and the western and central Chonnam area to determine the distribution of Lymnaea viridis, the intermediate host of Fasciola hepatica, and to study their life history during the different seasons. It had a wide distribution, existing all over the places, and the principal habitats of the snail were rice paddies. The life cycle was determined by making frequent visits to a series of habitats. The snsils began to produce egg masses in April, and egg production was the highest in May and June. Egg laying was continued but decreased in summer. There was sudden decrease in egg production in October when the temperature was below 2$0^{\circ}C$. The number of snails in July. Under the unfavourble conditions the snail either crawle up on the snail to aestivation. At low temperature below 8$^{\circ}C$ the snails hibernated inthe mud of the habitat. It was found in some habitats thao the snails were loving together with L. auricularia and Physa s pp. which indicates the neccessity of differentiation among them.