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Volume 16 (1972)
- Issue 4 Pages 171-
- Issue 3 Pages 121-
- Issue 2 Pages 59-
- Issue 1 Pages 1-
Volume 16, Issue 2
Displaying 1-11 of 11 articles from this issue
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III. Neurosecretory Axons and Corpus CardiacumYoshiaki KONO1972 Volume 16 Issue 2 Pages 59-66
Published: June 25, 1972
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSAxon processes of neurosecretory cells of the brain, distinguished by secretory granules with specific diameter, were investigated electron microscopically. Synapses from common neurone to neurosecretory axon were observed in the neuropile of the brain. Neurosecretory I cells and II cells in the pars intercerebralis, and neurosecretory IV cells in the dorso-lateral part of brain sent axons, through nervi corporis cardiaci I and II respectively, to the corpus cardiacum, and there they established axon terminals. Intrinsic neurosecretory cells with secretory granules with a diameter of 130-160mμ were also observed in the corpus cardiacum. The neurosecretory axon terminals at the corpus cardiacum were filled with secretory granules of various electron densities, and many synaptic vesicles (ca. 50mμ in diameter) also aggregated along the axon membranes. The appearance of these axon terminals, considered as for hormone release, were always observed from the prepupal to the earlier pupal stage of both diapause and non-diapause individuals. Characteristically, just after pupation of the non-diapause insect when neurosecretory materials were vigorously released, many vacuolated parts appeared in the axons of the neurosecretory II cell together with synaptic vesicles and secretory granules.View full abstractDownload PDF (5961K) -
Akira TAKAI, Keinosuke HARA, Minoru INO1972 Volume 16 Issue 2 Pages 67-74
Published: June 25, 1972
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSFluctuation in the number of overwintering Nephotettix cincticeps was studied during a period of 3 years at 3 localities. For the estimation of the number of individuals, “quadrate-suction” method was used together with the removal (time-unit capture) method. In the over-wintering generation, mortality of eggs and young nymphs seemed to be caused mainly be the effect of temperature. Death of hibernating nymphs was observed mainly during the period from December to the first 10 days of January in different years and localities. Survival rate of the 4th instar nymphs in winter was usually high as compared with other the developmental stages.
The blowing method captured 20%-50% of insects. Sampling efficiency of this method was lower than the “quadrate-suction” method, and was affected considerably by temperature. Spiders played an important role in reducing the number of N. cincticeps during winter.View full abstractDownload PDF (1693K) -
Shoei OTSU1972 Volume 16 Issue 2 Pages 75-78
Published: June 25, 1972
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSThe materials used in this investigation were collected during the period from December 1st, 1968 to February 15th, 1971 (during the hunting season). Fifty one individuals of the aminal were obtained at the foot of Mt. Iide and Mt. Asahi. The stomach content showed that the foods taken by the animal were consisted of 3 species of birds, 3 species of mammals and 2 kinds of berries. Japanese Cooper Phesant, Phasianus soemmeringii scintillans (GOLD) and Tohoku hare, Lepus brachyurus angustidens HOLLISTER were of frequent occurrence, making respectively 47% and 30% of the total weight of the stomach content. It is noted that there were fruits of the persimmon, Diospyros Kaki THUNB., showing 8% of the total weight. The statistics of the Ministry of Agriculture indicates that the number of Japanese marten is gradually decreasing in the wild of Japan.View full abstractDownload PDF (522K) -
Naotoshi KAKIYA, Keizi KIRITANI1972 Volume 16 Issue 2 Pages 79-86
Published: June 25, 1972
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSIn the green rice leafhopper, Nephotettix cincticeps, flight ability of adults in relation to the number of days that elapsed after their emergence (Expt. I), the influence of maternal age (Expt. II), and of rearing density (Expt. III) upon flight activity of adults were studied by tethered flight experiments. The insects used in Expt. I had been reared at 25°C, under 24hr illumination, while those in Expts. II and III, were reared at 30°C, under 16hr illumination. The tethered flight experiment was conducted at a temperature of 30°C with a headwind of 1-2m/sec. From the 2nd day after emergence in the case of the female and 4th day in the male, the adults began to fly, and on about the 8th day, which was 1 or 2 days before oviposition (the mean pre-oviposition period was 9.7 days), the flight duration and percentage of adults which flew attained their maxima. Differences between “fly” and “non-fly” adults in their flight activity and in the physiological characteristics were compared with each other among the progeny derived from different ages of famale adults: 1st to 3rd (young mother), 6th to 8th (middleaged mother) and later than 11th (old mother) day after the beginning of oviposition. In the offspring derived from young mothers, the “fly” adults had inferior physiological characteristics, e.g. shorter life span of adult, longer preoviposition period, and lesser number of eggs deposited, compared with those of the “non-fly, ” but these relationships were reversed for offspring from old mothers. These facts suggested that there existed a tendency of specialization of migrants and residents among offsprings produced from young mothers, and that only vigorous individuals are able to fly among those from old mothers. Flight activity was compared between adults which had been reared as nymphs at a high population density (5 larvae/tube) and isolated. The former had high flight activity and inferior physiological characteristics compared with the latter. This suggested that the high larval population density urges the specialization of migrants and residents. In this respect, population density during adulthood was ineffective.View full abstractDownload PDF (1041K) -
Azusa FUJIIE1972 Volume 16 Issue 2 Pages 87-93
Published: June 25, 1972
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSThe frequency distribution of individuals per plant of the two aphid species, Dactynotus formosanus TAKAHASHI and Myzus persicae SULZER, was investigated in lettuce fields at the Chiba Agricultural Experiment Station. It was suggested that the frequency distribution of individuals per plant of these aphids was a highly contagious one. No relationship was found between the value of Iδ-index and the mean density. In the autumn populations, the values of Iδ-index of D. formosanus were generally larger than those of M. persicae. In D. formosanus, Iδ values were larger in autumn than in spring. Sample size necessary for assuring a given precision was calculated by using the value of the Iδ-index. On a condition that the mean was between 1.0 and 1.5, more than 200 plants were needed to assure a desired precision. The frequency distribution of individuals per plant was represented by a negative binomial distribution in all the populations of the two species. In the autumn population of D. formosanus the value of common k of the negative binomial distribution was estimated to be 0.0331, when the calculation was restricted to the cases of x≤1.5. A preliminary test of the sequential sampling plan and the estimation of the mean of individuals based on the frequency of non-infested plants were made using the value of common k obtained. A linear relationship appeared between the number of individuals per plant and the percentage of infested plants, and this suggested the possibility of estimating aphid density by using this relationship.View full abstractDownload PDF (733K) -
Control with Selective, Low Dosage Insecticides by Reduced Number of ApplicationsKeizi KIRITANI, Takashi INOUE, Fusao NAKASUJI, Sachio KAWAHARA, Takaji ...1972 Volume 16 Issue 2 Pages 94-106
Published: June 25, 1972
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSIn an attempt to develop an integrated control programme for rice pests, a feasibility study to control rice pests with minimum number of applications of selective insecticides at low rates was explored from 1969 to 1971. The number of hoppers (Nephotettix cincticeps, Laodelphax striatellus, Sogatella furcifera and Nilaparvata lugens), and spiders (Lycosa, Oedothorax, Tetragnatha, and Theridion) and the stalks infested by Chilo suppressalis were counted weekly by direct observation. Aiming to replace BHC with other non-persistent and selective insecticides, the effectiveness of some organophosphates, i.e. MEP and diazinon, was tested in comparison with BHC in 1969. The organophosphates were not only more effective in controlling boresr's infestation but also yielded much more crop than BHC. In 1970, the feasibility of reducing the number of insecticidal treatments was examined. Also a comparison was made between different formulations, i.e. granule and dust, with their respective effect on spiders and the effectiveness for the control of rice pests. BPMC was very effective on hoppers and chlorophenamidine, Cartap and MEP were so on the borer, but they were less toxic to spiders. The rice yield was increased by use of these selective insecticides with reduced number of applications, by 1-3 times, as compared with the commercial control programme. The granular formulation of insecticides gave satisfactory control of rice pests with less influence on spiders than the dust formulation. But the high content of the active ingredient in the granular formulation remains to be solved. An attempt was made in 1971 to control rice pests with a low dosage, and with minimum number of insecticidal treatments, i.e. two times during the growing season. The insecticides used were chlorophenamidine and Cartap for the borer, and BPMC for hoppers. Satisfactory control of hoppers was attained with only one application of BPMC, whereas it was impossible to assess the effectiveness of chlorophenamidine and Cartap on the borer due to its low population density at the time of investigation.View full abstractDownload PDF (1599K) -
1972 Volume 16 Issue 2 Pages 106
Published: 1972
Released on J-STAGE: February 12, 2009
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Atsushi KOKUBO1972 Volume 16 Issue 2 Pages 107-109
Published: June 25, 1972
Released on J-STAGE: February 12, 2009
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Zenzaburô ÔGANE1972 Volume 16 Issue 2 Pages 109-111
Published: June 25, 1972
Released on J-STAGE: February 12, 2009
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Shigeo MURAKOSHI1972 Volume 16 Issue 2 Pages 111-113
Published: June 25, 1972
Released on J-STAGE: February 12, 2009
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Kazuo NAKAMURA1972 Volume 16 Issue 2 Pages 113-114
Published: June 25, 1972
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSDownload PDF (277K)
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