• International Journal of Industrial Entomology and Biomaterials
• /
• v.9 no.2
• /
• pp.241-247
• /
• 2004

It was investigated whether or not flight has any effects on oviposition and colony development of the artificially hibernated Bombus terrestris queen and ,$CO_2$-treated queen. Flight periods were defined as 0 days (control), 1 day, 3 days and 6 days. The weights of queens after flight were 1.5-8.9% lower than those before flight depending on the flight periods. The oviposition and colony development of artificially hibernated and $CO_2$-treated B. terrestris queen were affected by the flight. Among flight periods tested, in particular, the queens start to flight for 3 days showed better flight effect than those other flight periods in the colony development, rate of colony foundation, rate of progeny-queen production, the number of worker and queen produced. But, the longer the flight periods is, the worse the oviposition and colony development of the queens hibernated artificially and $CO_2$-treated are (i.e., the 6 days-flight queen).

• Korean journal of applied entomology
• /
• v.44 no.3 s.140
• /
• pp.199-205
• /
• 2005

Seasonal occurrence and ovarian development of the bean bug, Riptortus clavatus Thunberg (Heteroptera: Alydidae), were studied at a soybean field and an university campus in which host plants are less available for the bug in Gyeongnam province with aggregation pheromone traps in 2004. It was assumed that the bug passed three generations per year at the university campus. Adults of the 1st generation might occur from early July to early August and that of the 2nd one from mid August to late September. Adults of the 3rd generation occurred from early October to mid November, entered reproductive diapause without carrying eggs in the ovaries of females during winter, and resumed activity from late March of the next year. Full-grown eggs in the ovaries of the overwintered females were first observed at the 1st half of May. Two peaks of occurrence, from early August to mid September and from mid October to mid November, were shown at soybean field that was sowed on May 24. The two peaks almost corresponded to those of the 2nd and 3rd generations at the university campus, respectively.

• Development and Reproduction
• /
• v.25 no.4
• /
• pp.269-277
• /
• 2021

Effects of water temperature and hormones on ovarian development of conger eel in Korea were investigated. Ovarian development was analyzed by measuring gonadosomatic index (GSI) and oocyte diameter with histological methods. At rearing water temperatures of 12℃, 14℃, and 16℃, GSI value increased from 3.66 at the start of the experiment to 7.44, 8.82, and 7.34 at the end of the experiment, respectively. At rearing water temperatures of 12℃, 14℃, and 16℃, egg diameter increased from 245.11-300.25 ㎛ at the start of the experiment to 377.62-480.27 ㎛, 396.72-498.54 ㎛, and 382.29-475.69 ㎛ at the end of the experiment, respectively. Follicular oocyte development revealed that primary yolk globule stage observed from January to March. It entered to secondary yolk globule stage in April and remained at the same stage until July. As a result of examining effects of three hormones (human chorionic gonadotropin (HCG), luteinizing hormone releasing hormone analogue (LHRHa), and salmon pituitary extraction (SPE) on ovarian development, HCG was found to be the most effective one. The progress from diapause of the secondary yolk globule stage to migratory nucleus stage of oocytes could be induced by treating fish with HCG at 1,000 IU/kg. The effect of hormone treatment on ovarian development of conger eel in Korea was the most effective at water temperature of 14℃.

• Korean journal of applied entomology
• /
• v.48 no.2
• /
• pp.221-227
• /
• 2009

Temperature effects on diapause termination of Paratlanticus ussuriensis eggs were studied by measuring embryonic development and hatching rates at various conditions of indoor chilling and overwintering temperatures. Diapausing eggs of P. ussuriensis did not hatch at continued incubation at $25^{\circ}C$ and even after chilling for once at either $5^{\circ}C$ or $10^{\circ}C$ for 30, 45 and 60 days. In addition, double chillings at $5^{\circ}C$ with a 90 days interval at $25^{\circ}C$ did not induce hatching of diapausing eggs. However, double chillings at $10^{\circ}C$ induced hatching at 3.6${\sim}$26.7%. When eggs were incubated at $25^{\circ}C$ after chilling for once at $5^{\circ}C$ for various periods, those weights were not changed but those chilled at $10^{\circ}C$ gradually increased to approximately 1.5 times. When 60-days-old eggs were artificially deposited under the soil at three different mountain sites in September 2007, the hatching rates of the first-overwintered eggs were 11.3, 3.5 and 4.1% and those of the second-overwintered eggs were 25.1, 21.6 and 0.4% at Hoepori, Bitanri and Hwasanri, respectively. Most eggs were hatched from mid-March to mid-April but little bit earlier in southern regions. During the hatching period soil temperatures in three tested locations were around 8 to $12^{\circ}C$. In overall, diapausing eggs of P. ussuriensis were greatly influenced by chilling temperature conditions and those repeated cycles, and may required overwintering for one or two times to hatch for the post-embryonic development.

• Korean journal of applied entomology
• /
• v.61 no.3
• /
• pp.409-422
• /
• 2022

Two dominant thrips in hot pepper (Capsicum annuum) cultivating in greenhouses are Frankliniella occidentalis and F. intonsa in Korea. This study investigated their overwintering physiology. These two thrips were freeze-susceptible and suppressed the body freezing temperature by lowering supercooling point (SCP) down to -15~-27℃. However, these SCPs varied among species and developmental stages. SCPs of F. occidentalis were -25.7±0.5℃ for adults, -17.2±0.3℃ for pupae, and -15.0±0.4℃ for larvae. SCPs of F. intonsa were -24.0±1.0℃ for adults, -27.0±0.5℃ for pupae, -17.2±0.8℃ for larvae. Cold injuries of both species occurred at low temperature treatments above SCPs. Thrips mortality increased as the treatment temperature decreased and its exposure period increased. F. occidentalis exhibited higher cold tolerance than F. intonsa. In both species, adults were more cold-tolerant than larvae. Two thrips species exhibited a rapid cold hardening because a pre-exposure to 0℃ for 2 h significantly enhanced the cold tolerance to a lethal cold temperature treatment at -10℃ for 2 h. In addition, a sequential exposure of the thrips to decreasing temperatures made them to be acclimated to low temperatures. To investigate the overwintering sites of the two species, winter monitoring of the thrips was performed at the greenhouses. During winter season (November~February), adults of the two species were not captured in outside of the greenhouses. However, F. occidentalis adults were captured to the traps and observed in weeds within the greenhouses. F. occidentalis adults were also emerged from soil samples obtained from the greenhouses during the winter season. F. intonsa adults did not come out from the soil samples at November and December, but emerged from the soil samples obtained after January. To determine the adult emergence due to diapause development, two thrips species were reared under different photoperiods. Adult development occurred in all photoperiod treatments in F. occidentalis, but did not in F. intonsa especially under short periods. Tomato spotted wilt virus, which is transmitted by these two species, was detected in the weeds infested by the thrips during the winter season. These results suggest that F. occidentalis develops on weeds in the greenhouses while F. intonsa undergoes a diapause in the soil during winter.

• Korean journal of applied entomology
• /
• v.42 no.2
• /
• pp.139-144
• /
• 2003

The effect of $CO_2$-treatment on interrupting diapause of Bombus ignitus was examined to provide a means for year-round rearing of the bumblebee. When mated young queens were exposed to 65% or 99% $CO_2$ for 30 min daily during two consecutive days, oviposition rate increased to 75% and 77%, respectively, comparing 50% in $CO_2$-untreated queens. At the same time, the days needed to first oviposition shortened to 17-18 days in $CO_2$-treated queens, comparing to 30 days in $CO_2$-untreated queens. $CO_2$-treatment at the second day after mating was appropriate to the oviposition and colony development. $CO_2$-treatment showed a positive effect on the oviposition and colony development, but less than them of overwintered queen in numbers of produced progeny. It can be concluded that $CO_2$-treatment to B. ignitus is insufficient to produce commercial grade bumblebee colony in spite of its capability for promoting oviposition, because the treatment failed to form a big colony.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.19 no.1
• /
• pp.155-164
• /
• 2009

The most important factors in environment that influence the physiology of insects are temperature and humidity. Insects display a remarkable range of adaptations to changing environments and maintain their internal temperature (thermoregulation) and water content within tolerable limits, despite wide fluctuations in their surroundings. Adaptation is a complex and dynamic state that widely differs in species. Surviving under changing environment in insects depends on dispersal, habitat selection, habitat modification, relationship with ice and water, resistance to cold, diapause and developmental rate, sensitivity to environmental signals and syntheses of variety of cryoprotectant molecules. The mulberry silkworm (Bombyx mori) is very delicate and sensitive to environmental fluctuations and unable to survive naturally because of their domestication since ancient times. Thus, the adaptability to environmental conditions in the silkworm is quite different from those of wild insects. Temperature, humidity, air circulation, gases and photoperiod etc. shows a significant interaction in their effect on the physiology of silkworm depending upon the combination of factors and developmental stage affecting growth, development, productivity and quality of silk. An attempt has been made in this article to briefly discuss adaptation in insects with special emphasis on the role of environmental factors and their fluctuations and its significance in the physiology of mulberry silkworm, B. mori.

• Korean journal of applied entomology
• /
• v.50 no.3
• /
• pp.253-256
• /
• 2011

The walnut leaf beetle, Gastrolina depressa, belongs to family Chrysomelidae (Coleoptera), and is one of the major pests of walnut trees. G. depressa eggs were oval and dark orange. The three G. depressa larval instars were gray in color. The larval period was approx. 8.14 days ($24^{\circ}C$, 16L:8D). Adults of both sexes were dark blue, and females were larger than males. Overwintered adults emerged in late April, and laid eggs in clusters on young leaves of the host tree. Mature 3rd instar larvae pupated after a short prepupal period. Adults emerged starting mid-May and entered into diapause shortly afterward.

• Korean Journal of Environment and Ecology
• /
• v.34 no.4
• /
• pp.274-281
• /
• 2020

This study aimed to investigate the autumn spawning by bitterling (A. rhombeus) inside mussel (Unio douglasiae) and the adaptation characteristics at the Bongseocheon Stream of Mankyeonggang River. The survey was carried out between August 2015 and July 2016. The spawning season was from September to November, and 17-75 (36.2 ± 16.44) eggs were found from mature females. During the survey period, 476 mussels were collected, 129 (27.1%) of spawned A. rhombeus. Mussels that spawned eggs, embryos, and larva of A. rhombeus (46.3 ± 4.55 mm, n = 129) were larger than than those that did not spawn (42.6 ± 8.51 mm, n = 347). The appearance frequency of A. rhombeus larva before and after the formation of lens was 99.8% (n = 597) vs. 0.2% (n = 1) from October 2015 to March 2016, 25.6% (n = 23) vs. 74.4% (n = 67) in April 2016, 0% (n = 0) vs. 100% (n = 40) on May 2016. The number of eggs, embryos, and larvae of A. rhombeus inside the mussels were 1-18 (5.6 ± 3.81). The number and appearance frequency of A. rhombeus eggs, embryos, and larvae inside the mussel according to mussel gill demibranchs position were 1 (0.01 ± 0.09, n = 1) and 0.78% in the left outer demibranch, 1-18 (2.33 ± 3.31, n = 63) and 48.84% in the left inner demibranch, 1-15 (2.97 ± 3.79, n = 76) and 58.91% in the right inner demibransh, and 1-12 (0.33 ± 1.71, n = 7) and 5.43% in the right outer demibransh. The highest frequency of the developmental position of eggs, embryos, and larvae occurred 71.8% (n = 445) in lower part 3 (L3) before formation lens and 94.4% (n = 102) in L3 after formation lens, indicating that L3 was dominating position for eggs, embryos, and larvae. More eggs, embryos, and larvae of A. rhombeus were found more often in the inner demibranshs than outer demibranchs. Since A. rhombeus is a species that spawn in the autumn and thus avoids the competition with interspecific and glochidia. However, they have to spend the winter in low water temperature. Consequently, we assume that A. rhombeus have evolved toward embryonic diapause under the low water temperature before the formation of lens and spawning inside the supracranchial cavity to save the transit energy from the water space to the suprabranchial cavity after the achieving movement ability with the formation of lens.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.18 no.2
• /
• pp.113-120
• /
• 2009

Embryonic lethal abnormal visual (elav) is a lethal gene in Drosophila inducing the abnormal development and function of nervous system. We cloned a Bm-elav gene by bioinformatics and biological experiment, based on sequence of ELAV protein and dbEST of Bombyx mori. The full-length of Bm-elav cDNA is 1498 bp, contains a 906 bp open read frame (ORF) encoding a precursor of 301 amino acid residues with a calculated molecular weight of 34 kDa and pI of 8.99. Bm-ELAV protein precursor contains three RNA recognition motifs (RRM) in $24{\sim}91$, $110{\sim}177$ and $222{\sim}295$ bit amino acid residues respectively, and belongs to RNA-binding protein family. Bm-ELAV shared varying positives, ranging from 56% to 60% (Identities from 41% to 45%), with RRM from other species of Xenopus tropicalis, Apis mellifera, Tribolium castaneum, Branchiostoma belcheri and Drosophila. Gene localization indicated that Bm-elav is a single-copy gene, gene mapping within 12-chromosome from 7916.68 knt to 7918.16 knt region of nscaf2993. Spatiotemporal expressions pattern analysis revealed that Bm-elav expressed higher in most tested tissues and developmental stages in whole generation, such as silk gland, fat body, midgut, hemopoietic organ and ovary, but almost no expression in terminated diapause eggs. This suggested that the expression of Bm-elav in early developmental embryonic stages might induce abnormal development like in Drosophila. Cloning of the Bm-elav gene enables us to test its potential role in controlling pests by transferring the gene into field lepidopteran insects in the future.