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Volume 24 (1980)
- Issue 4 Pages 205-
- Issue 3 Pages 137-
- Issue 2 Pages 49-
- Issue 1 Pages 1-
Volume 24, Issue 3
Displaying 1-9 of 9 articles from this issue
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I. The Effect of Larval Aggregation and its FormHiroshi NAKAMURA1980 Volume 24 Issue 3 Pages 137-144
Published: August 25, 1980
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSLarvae of Neodiprion sertifer (GEOFFROY) live in compact aggregation throughout their larval period. Larvae were reared in different group sizes to evaluate the aggregation effects on the larval mortality, the larval development and the weight of cocoons. Laboratory experiments and observations of natural larval groups were conducted to define the characteristics of larval aggregation. The durations of the first and second instars were much longer in the isolated rearings than in the group ones. There was no difference in the weight of cocoons among all the rearing groups. The survival rates were 55-60% in the rearing groups with 1, 2, 3 and 5 larvae, and 77% in those with 7 larvae. Larvae in the rearing groups comprising 10 and 20 individuals seldom died. The mortality of larvae which were reared on dry needles became higher with the decrease in the group size. The values of *m which were calculated on the basis of the number of larvae per one needle for natural groups became smaller at feeding time and higher at moulting time. It was observed that at feeding time several larvae formed a small group at the feeding site on each needle and at moulting time many larvae moved to the lower part of needle and formed a tight aggregation there. It was found that aggregation of N. sertifer involved two types, i.e., “feeding group” which was composed of several larvae per one needle at feeding time and “moulting group” which was formed by many larvae at moulting time. The ecological significance of these two types of larval aggregation were discussed.View full abstractDownload PDF (1469K) -
III. Effects of Growth Stage of Corn on Survival and Weight of the LarvaeOsamu SAITO1980 Volume 24 Issue 3 Pages 145-149
Published: August 25, 1980
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSThe first generation larvae of oriental corn borer were fed dent corns at the vegetative or the reproductive stage, and the second generation larvae were fed corns at the ripening stage in Morioka, Tohoku district. Upon the examination of the specimens from a dent corn field, it was found that the second generation larvae showed higher survival and developed into slightly lighter pupae than those of the first generation. In green house experiments with potted dent corns, the larvae fed upon the late reproductive stage of corn showed the highest survival and the heaviest weight of all. Larvae fed upon the vegetative stage of corn showed low survival and low weight. At the late ripening stage of corn, the larvae showed high survival, but low weight. From the results obtained, it was concluded that the differences in survival and weight of larvae between two generations in the field could be ascribed to the difference in growth stages of corn fed to the larvae.View full abstractDownload PDF (623K) -
III. Control Threshold Density and Sampling SizeKazuo EMURA, Akio KOJIMA1980 Volume 24 Issue 3 Pages 150-156
Published: August 25, 1980
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSIn Niigata Prefecture, larvae of the rice leaf beetle injured rice leaves from the beginning to the end of June, and reduced the yield of rice. The best time for controlling this pest with insecticides was when hatching of the larvae was at its peak, which corresponded to the 4th-5th day after the peak of oviposition. On the basis of the relationship between the damage caused by the 3rd and 4th instar larvae and the survival rates from egg to the 3rd instar, the control threshold density, as determined by the peak egg density at the beginning of June, was about 8 eggs per hill. The eggs were laid in masses on rice leaves, and the masses were distributed randomly in a paddy field. The practical sample size required for determining the control threshold of eggs, with a reasonable precision was 36 hills per paddy field (18 points×2 hills). On the other hand, the control threshold in terms of the peak density of immigrated adults in the paddy field was estimated at about 0.1 beetles per hill. The best time for insecticide application coincided with the 10th day of peak adult density. But, this control threshold value was less precise as compared with that obtained for the eggs. The distribution of the adults in the paddy field was aggregated. The sample size required for making a decision on insecticide application was 100 hills (4 points×25 hills) per paddy field for adults.View full abstractDownload PDF (952K) -
Hideaki MAEKAWA, Keisuke KIMURA, Naoko SAISHU, Hiromu AKAI1980 Volume 24 Issue 3 Pages 157-166
Published: August 25, 1980
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSTwo lines of larvae producing large amount (L-line) and small amount (S-line) of silk fibroin, respectively had been selected over 50 generations derived from the Pyrénées Bombyx mori, belonging to the European race, and the posterior silk glands of the lines were used as materials. There were no differences between the L-line and wild type with respect to the intracellular structure and the amount of nucleic acids. In the case of the S-line, however, numerous differences were identified such as a decreased ramification of nuclei, a smaller number of nucleoli, variations in the distribution of the lamellar structure of endoplasmic reticulum and a decreased number of elementary fibroin fibers in the Golgi complex. The observations indicate that the intracellular organelles are inactivated with respect to the production of fibroin in the S-line. Although the synthesis ratio of ribosomal RNA and fibroin mRNA could not be distinguished between the two lines, the amount of DNA and RNA's of the S-line was about 30% lower than that of the L-line. It was suggested that the ultrastructural changes in the S-line were caused by the decreasing amount of all RNA species including fibroin mRNA resulting from a small amount of DNA.View full abstractDownload PDF (7142K) -
Taira ICHINOSÉ, Shirô SHIBAZAKI, Masayoshi OHTA1980 Volume 24 Issue 3 Pages 167-174
Published: August 25, 1980
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSRecently a massive outbreak of the Tenebrionid, Alphitobius diaperinus PANZER has been observed in broiler-chicken houses in various parts of Japan and adiabatic materials such as polyurethane- or polystyrene foam which line the walls were damaged seriously by boring of the insect. Investigations were carried out to explore the reason why such infestation had occurred. The development of A. diaperinus was promoted by the high temperature around 30°C and high population density, but was inhibited at a temperature of 15°C in every developmental stage. Three-day exposure of eggs at 7°C gave only 2 per cent hatching. Water deficiency also prevented breeding from taking place. The strong activity of amylase enabled to confirm that the insect was a typical stored product pest depending on feedstuff rich in starch. The relationship between activity and temperature was consistent with that of the developmental velocity and the temperature, with maximum values at 35°C. Only old-age larvae did bore into various adiabatic materials, while younger ones and adults did not, and they failed to survive on these materials. Some coatings of the materials prevented boring. These results indicate that the injury is caused merely by the requirements of a pupation site by the mature larvae and that the thermal, moist and trophic conditions in broiler-houses are conducive to the development and multiplication of the insect.View full abstractDownload PDF (1757K) -
Masato UCHIDA1980 Volume 24 Issue 3 Pages 175-183
Published: August 25, 1980
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSThe appearance of diapausing females of two mite species (Tetranychus urticae KOCH and T. kanzawai KISHIDA) was observed at the critical photoperiod of about 12 hours at the intermediate temperature of 16°C, and about 50% diapausing females appeared in early October in Tottori District. The diapausing females of T. urticae overwintered in groups under the roughened bark and those of T. kanzawai overwintered under fallen leaves and tight rope knots of lateral shoot. It was found that there was a high correlation between the number of summer females on leaves in late September and the amount of overwintering females. Diapause was broken in about 70% of the females of T. kanzawai collected from pear orchard on November 15, by chilling at about 4°C for 29 days, and in about 50% of the females of T. urticae the diapause was broken by exposure to a temperature of about 4°C for 41 days. But it was observed that in about 60-90% of females of the two species diapause ended in late December in the field. The number of detached females from overwintering areas increased linearly from late February to early March. This phenomenon was completed in late March in T. kanzawai, whereas in T. urticae it extended up to mid-April.View full abstractDownload PDF (1163K) -
Seiya KAMANO1980 Volume 24 Issue 3 Pages 184-188
Published: August 25, 1980
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSThe bean bug, which is a harmful pest of soybeans in Japan, can be reared on artificial solid diet and water. The best diet which is composed of soybean casein, a mixture of 19 amino acids, starch, saccharose, cellulose powder, salt mixture, cholesterol, ascorbic acid and a combination of 9 vitamines, supported the growth and development of the insect from the egg to the adult stage as in the case of soybeans. When one of the nutrients such as starch, casein, mixture of amino acids or cholesterol was omitted from the basal diet, adverse effects appeared on the growth and development, and no adults were obtained. The growth of nymphs reared on the diet which did not include cellulose, saccharose, ascorbic acid or vitamin mixture, was retarded although a few adults appeared. No difference in nymphal growth and development was noted when these were reared on the diet without salt mixture.View full abstractDownload PDF (593K) -
Hisaaki TSUMUKI, Katsuo KANEHISA1980 Volume 24 Issue 3 Pages 189-193
Published: August 25, 1980
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSEffect of low temperature on glycerol and trehalose concentration in haemolymph of rice stem borer larvae was studied. Glycerol formation in haemolymph of the mature larvae reared at 25±1°C was observed when these were stored at low temperatures such as 15°C, 10°C and 4°C, especially at 10°C. In the larvae reared at 25±1°C, glycerol formation in haemolymph of diapausing larvae induced under short day photoperiod was higher than that of non-diapausing types under long day photoperiod at low temperatures. However, once the diapause induced under short day photoperiod was broken by exposure to low temperature, glycerol concentration in haemolymph decreased. These phenomena were also observed in hibernating larvae collected in fields. Glycerol production was stimulated in non-diapausing larvae treated with JH-I. These observations show that in the rice stem borer glycerol formation may be related to diapause and low temperature. Trehalose concentration in haemolymph appeared to be more closely related to low temperature than to diapause.View full abstractDownload PDF (555K) -
Nozomu FUJIYOSHI, Masaharu NODA, Hisao SAKAI1980 Volume 24 Issue 3 Pages 194-196
Published: August 25, 1980
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSDownload PDF (989K)
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