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Chiharu KOSHIO
1997 Volume 32 Issue 2 Pages
273-281
Published: May 25, 1997
Released on J-STAGE: February 07, 2008
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The gypsy moth, Lymantria dispar L, in Japan showed two patterns of copulation; duration type I and type II. Type I copulation was the more typically seen type and was sufficient to fertilize almost all of a female's eggs. Type II copulation continued until the female began pre-ovipositional behavior and occurred when other males were attracted to the copulating pair. Type II copulation, therefore, appears to be a mate guarding strategy by males. Males changed their strategies from mate searching to mate guarding in response to disturbances by other males.
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Satoshi NAKAMURA
1997 Volume 32 Issue 2 Pages
283-291
Published: May 25, 1997
Released on J-STAGE: February 07, 2008
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The ability of Exorista japonica females to regulate clutch size in response to host density was investigated in the laboratory. On the assumption that the flies can estimate host density by the frequency of host encounters, the effect of time interval between host encounters and the number of hosts offered on the oviposition decision of female flies was studied, and host discriminatory ability was examined. A female fly was offered a cup (considered as a patch) containing host(s) at various time intervals. Clutch size decreased as the time interval between host encounters was shortened and as host density per patch increased. The number of eggs laid per patch during a single attack increased with increases in the time interval between host encounters was lengthened and as host density per patch increased, even at a constant time interval. Females discriminated between unparasitized and parasitized hosts when the parasitized host contained 10 eggs, but did not discriminate when the parasitized host had only 5 eggs. Moreover, the time interval between host encounters affected host discrimination. Females oviposited equally on an unparasitized and a parasitized host with 10 eggs when they encountered hosts at 24 h intervals, but they laid fewer eggs on the parasitized host when the interval between host provisions was 1 min. the results indicated that E. japonica females not only regulated clutch size in relation to host availability but also discriminated between unparasitized and parasitized hosts.
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Yoshiaki KONO, Masakazu TAKAHASHI, Minoru MIHARA, Kazuhiro MATSUSHITA, ...
1997 Volume 32 Issue 2 Pages
293-301
Published: May 25, 1997
Released on J-STAGE: February 07, 2008
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Injection of a specific trehalase inhibitor, validoxylamine A(VAA), suppressed oocyte development in the American cockroach, Periplaneta americana. Ootheca formation was also affected by the same treatment. Inhibition of trehalases of ovaries and thoracic muscles in P. americana in vitro by VAA was very strong; I
50 values were 5.0×10
-9 M and 1.4×10
-8 M, respectively. When the inhibition of trehalase activity was measured after injection of VAA(5 and 50 μg/insect) into cockroaches, more than 90% of the activity in the ovaries was inhibited. The high level of inhibition lasted 2 weeks at the higher dosage, but recovery activity was observed in the second week following the injection of the lower dosage. VAA injection also inhibited the muscular trehalase but to a lesser degree than the ovarian trehalase. Enhancement of haemolymph trehalose concentration and the maintenance of its higher level after the injection of VAA suggested strong inhibition of trehalase in various tissues of the cockroach. It is speculated that the uptake of materials required for oocyte development as well as the energy supply was prevented through the inhibition of trehalase.
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Masatoshi HORI, Hiroaki KOMATSU
1997 Volume 32 Issue 2 Pages
303-310
Published: May 25, 1997
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Olfactory behaviors of Neotoxoptera formosama, an aphid pest of allium crops, to host and non-host plant odors were investigated with a linear track olfactometer. Aphids were significantly attracted to odors of host plants, Allium fistulosum and A. tuberosum. On the contrary, they were repelled by odors of non-host plants, rosemary and pennyroyal. The odor of pennyroyal masked the attractiveness of host plant odor and the odor of rosemary repelled aphids even in the presence of host plant odor. Rosemary oil also had a repellency effect against aphids, and repelled them even in the presence of host plant odor. Six components of rosemary oil identified by GC-MS analysis, 1, 8-cineole, d, l-camphor, α-pinene, etc., showed this repellency as well. 1. 8-Cineole and d, l-camphor repelled aphids even in the presence of host plant odor and α-pinene masked host plant attractancy. 1, 8-Cineole is the main component of rosemary oil and is thought to be main factor responsible for the repellency of rosemary. It was concluded that N. formosana may use host plant odors for host selection and be repelled by certain non-host plant odors. Rosemary volatiles may play an important role in defense of the plants from attack by parasites.
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Masaru HONDO, Naotake MORIMOTO
1997 Volume 32 Issue 2 Pages
311-316
Published: May 25, 1997
Released on J-STAGE: February 07, 2008
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Population changes of the mulberry tiger moth, Thanatarctia imparilis and the carabid beetle Parena perforata, a nest inhabiting specialist predator of its larvae, were analyzed. The number of T. imparilis colonies decreased suddenly from 1989 to 1991 and, gradual increased thereafter from 1991 to 1995. The carabid beetle was observed in ca. 90% of the prey colonies in 1990, however, it was not observed in 1991 and 1992. From 1993 to 1995, the density of P. perforata increased with the increase in density of T. imparilis. About 90% of T. imparilis larval colonies were destroyed before entering hibernation in 1990, while the destruction of larval colonies was only ca. 10% both in 1993 and 1994. although the predation by P. perforata acted strongly during the declining phase of the T. imparilis population, it did not act during the increasing phase. It was suggested that P. perforata is an important factor in regulating T. imparilis populations.
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Susumu NAKANO, Koji NAKAMURAI, Idrus ABBAS
1997 Volume 32 Issue 2 Pages
317-323
Published: May 25, 1997
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A Sumatran phtophagous lady beetle, Epilachna enneasticta was reared under laboratory conditions in order to study its survivor ship and fertility schedules. E. enneasticta required 28.7 days for development of the immature stages. The mean longevity of males (90.4 days) was longer than that of females (71.4 days). The mean length of the pre-reproductive period (30.1 days) was longer than that of the post-reproductive period (2.4 days). Females laid eggs continuously at a rather constant rate throughout their reproductive period and the average number of eggs produced per female was 425.4. the intrinsic rate of natural increase r was 0.070 per capita per day. E. enneasticta showed half to two-thirds of the mean fecundity, twice the pre-reproductive period, and a lower intrinsic rate of natural increase than three of its sympatric species in Sumatra (E. vigintioctopunctata, E. septima, and E. dodecastigma).
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Hirohisa KURAMOTO, Mitsuaki SHIMAZU
1997 Volume 32 Issue 2 Pages
325-331
Published: May 25, 1997
Released on J-STAGE: February 07, 2008
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Entomophthora muscae was introduced into model populations of house flies in an experimental windowless poultry house. Four hundred to 500 healthy flies were reared in 50 m
3 poultry rooms with 10 and 50 flies respectively infected with E. muscae. When the living infected flies were released into the room, they died within 7 days and the disease prevailed on non-injected flies with a peak of mortality about 18 days after the introduction. More than 90% of the initially healthy flies were killed by the disease including secondary infection over a period of 33 days. When conidia-discharging cadavers were attached to the inside of the room, the non-injected flies started to die 6 days after introduction of the cadavers and about 90% of the flies were killed including secondary infection within 20 days. Thus, epizootics of E. muscae could be induced by the introduction of living infected flies or fresh fly cadavers in a practical scale poultry house.
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Masahiro TAKAGI, Yoshio TSUDA, Wannapa SUWONKERD, Akira SUGIYAMA, Soms ...
1997 Volume 32 Issue 2 Pages
333-340
Published: May 25, 1997
Released on J-STAGE: February 07, 2008
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Larval mosquito communities in rice fields were examined monthly for 2 years at 3 study areas (15 subareas) near Chiangmai, Thailand. the temporal and spatial variations of community structure were analyzed based on the similarity of species composition among mosquito communities. Subareas were grouped depending on the similarity of the species composition. A large cluster which was composed of several small groups of subareas supporting mosquito communities of a similar species composition was observed in the rainy season. In the subareas of the large cluster, 2 Japanese encephalitis (JE) vector mosquitoes, Culex vishnui THEOBALD and C. tritaeniorhynchus GILES, occupied more than 60% of the mosquito communities, and a large number of JE vectors appeared from the rice fields. In the dry season, the large cluster of subareas disappeared and the species composition of the mosquito community varied greatly among the subareas. The successional change of mosquito colonization and an asynchronous cultivation of rice plants were suggested as important ecological factors related to the development of rice field mosquito communities.
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Takuya AIKAWA, Noritoshi MAEHARA, Kazuyoshi FUTAI, Katsumi TOGASHI
1997 Volume 32 Issue 2 Pages
341-346
Published: May 25, 1997
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A simple method for loading adult Momochamus alternatus with Bursaphelenchus xylophilus is presented. Statistical analyses indicated that vectors with larger nematode loads could be obtained in a shorter length of time from the nematode inoculation to vector larval introduction into substrate of Pinus densiflora bolt and the use of larger vector larvae.
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Yoshinori SHINTANI, Yukio ISHIKAWA
1997 Volume 32 Issue 2 Pages
347-354
Published: May 25, 1997
Released on J-STAGE: February 07, 2008
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Photoperiodic response of larval development in the yellow-spotted longicorn beetle, Psacothea hilaris (PASCOE), was examined at 20 and 30°C using six geographic populations collected in Japan (Akita, Oyama, Ayabe, Ino, Naze and Ishigaki). The results were compared with the responses at 25°C. By contrast, photoperiodic response at 20°C was largely different from that at higher temperatures. In the Ayabe and Ino populations, which showed clear long-day responses at higher temperatures, supernumerary molting (a characteristic of larval diapause in this species) was induced under both 12L: 12D and 15L:9D. Larvae of the Naze population also showed less clear long-day photoperiodic response. Most noticeably, larvae of the Akita, Oyama and Ishigaki populations, which did not show clear photoperiodic response at higher temperatures, expressed typical long-day responses at 20°C.
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Tomohide YASUNAGA
1997 Volume 32 Issue 2 Pages
355-364
Published: May 25, 1997
Released on J-STAGE: February 07, 2008
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This is the first part in a series of three papers which revise the seven species of the flower bug genus Orius WOLFF occurring in Japan and Taiwan. Herein two new species representing two new subgenera, Orius (Xylorius) miyamotoi from Kyushu, Japan and O. (Trichorius) atratus from the Ryukyus and Taiwan, are diagnosed, described and illustrated. General morphology and taxonomic characters are discussed.
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Koji HORI, Ayako WADA, Toumi SHIBUTA
1997 Volume 32 Issue 2 Pages
365-371
Published: May 25, 1997
Released on J-STAGE: February 07, 2008
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The galls on Ulmus leaves formed by Tetraneura fusiformis enlarged gradually from the 1st week of gall development to the 3rd week and rapidly from the 3rd to the 4th week, although no further enlargement was, thereafter, observed. Offspring began to be produced by the fundatrix from the 4th week and reached a maximum in number in the 5th week. thereafter, the number of offspring did not change until the 7th week. Dry weight of leaves with or without galls increased similarly from the 2nd to the 7th week, though the dry weight of the latter was higher than that of the former throughout the season. Maximums of peroxidase and polyphenoloxidase activities in non-galled leaves were observed in the 1st week and the zero week, respectively, and then those enzymatic activities gradually fell, whereas those in the galls were at a maximum in the zero or fist week, then dropped rapidly and were almost lost at the 2nd (peroxidase) or 4th week (polyphenoloxidase). These observations suggest that the process of formation and utilisation of galls by insects is apparently divided into two broad physiological stages before and after the 4th week.
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Li ZHANG, Toshio SHONO
1997 Volume 32 Issue 2 Pages
373-378
Published: May 25, 1997
Released on J-STAGE: February 07, 2008
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Toxicities of pyriproxyfen, a juvenile hormone analog, were studied by topical treatment to stages of houseflies from the 3rd instar larva to pupa of a susceptible SRS strain. the toxicities gradually increased from the early stage of the 3rd instar larva to the white pupal stage. Further studies indicated that the white pupa was the most susceptible stage to the chemical and the mortality of pupae decreased sharply after the white pupal stage. Pyriproxyfen susceptibilities were compared between the 3rd instar larvae and white pupae using SRS and YPPF (a pyriproxyfen resistant strain) houseflies, white pupae of the two strains were 130 and 440 times more sensitive than the 3rd instar larvae. White pupae of YPPF houseflies were 400-fold resistant to pyriproxyfen while the 3rd instar larvae were 12, 400-fold resistant. The results indicate that the white pupa is the most sensitive stage to pyriproxyfen and thus is thought to be a critical stage for the study of juvenile hormones and their analogs.
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Tomohide YASUNAGA
1997 Volume 32 Issue 2 Pages
379-386
Published: May 25, 1997
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The subgenus Heterorius WAGNER and four representative species occurring in Japan and Taiwan are diagnosed and/or redescribed. Orius similis ZHENG is proposed as a junior synonym of strigicollis POPPIUS. Orius nagaii YASUNAGA is reported from the Continental Russian Far East and Korea for the first time. Illustrations of the male and female genitalia, the most important taxonomic characters, and notes on habitat of each species are provided.
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Tomohide YASUNAGA
1997 Volume 32 Issue 2 Pages
387-394
Published: May 25, 1997
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The fourth subgenus of Orius from Japan and Taiwan, Paraorius YASUNAGA and MIYAMOTO, is diagnosed, and the single species included in the subgenus, Orius (P.) tantillus (MOTSCHULSKY) is reported from Japan with detailed distributional records and diagnosed. Keys to Japanese and Taiwanese subgenera and species are given. A note on an European species, O. laevigatus, recently introduced to Japan, and a check list of Orius species of the world are also provided. This is the final part of a series of revision treating Orius from Japan and Taiwan.
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Hidenari KISHIMOTO, Akio TAKAFUJI
1997 Volume 32 Issue 2 Pages
395-401
Published: May 25, 1997
Released on J-STAGE: February 07, 2008
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Several life-history parameters were compared among 3 populations of the phytoseiid mite, Amblyseius womersleyi SCHICHA, with different capacities for diapause. The parameters were monitored at 18, 20 and 25°C: 16L8D, at which diapause was not induced. Large variations were demonstrated among populations in the temperature effect on total oviposition and age-specific oviposition pattern. In the Aomori and Kyoto populations, which had high and intermediate diapause capacity, respectively, temperature affected total oviposition, and females laid significantly fewer eggs at 18 and 20°C than at 25°C in the Aomori population, and fewer at 18°C than at 20 and 25°C in the Kyoto population. On the other hand, in the Naha population which had a very weak diapause capacity, temperature did not affect the total oviposition. These results showed that the lower the capacity for diapause, the wider is the temperature range at which full reproduction is achieved.
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Yoshitaka NAKASHIMA, Yoshimi HIROSE
1997 Volume 32 Issue 2 Pages
403-405
Published: May 25, 1997
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Katsuyuki KOHNO, Yoshimi HIROSE
1997 Volume 32 Issue 2 Pages
406-409
Published: May 25, 1997
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Makoto HATTORI
1997 Volume 32 Issue 2 Pages
409-412
Published: May 25, 1997
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Manabu SHIBAO
1997 Volume 32 Issue 2 Pages
413-415
Published: May 25, 1997
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Yooichi KAINOH
1997 Volume 32 Issue 2 Pages
416-418
Published: May 25, 1997
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Sudawan CHAEYCHOMSRI, Motoko IKEDA, Michihiro KOBAYASHI
1997 Volume 32 Issue 2 Pages
418-421
Published: May 25, 1997
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