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Haruki Tatsuta, Gen Ito, Alexander G. Bugrov, Alexei A. Tchernykh, Shi ...
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
1-8
Published: 2000
Released on J-STAGE: October 31, 2002
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We examined morphological variation in Kunashiri populations of P. sapporensis Shiraki and P. tyatiensis Bugrov using multivariate morphometrics to clarify their taxonomic status in comparison with Hokkaido populations of P. sapporensis. Although P. sapporensis in Kunashiri Island has a unique karyotypic characteristic, the neo-X and neo-Y system, cluster analysis indicated that the morphology is included in the range of variation seen in Hokkaido populations with the XO-male determination system. P. tyatiensis is characterized by having short-armed chromosomes compared with other Podisma species, but the morphology of this species did not differed much from P. sapporensis in Hokkaido, either. These results suggest that chromosomal changes do not contribute to phenotypic diversification. P. sapporensis in Kunashiri Island is probably reproductively isolated from P. tyatiensis on the same island because of conspicuous differences in the karyotype, whereas it is highly probable that P. tyatientsis in Kunashiri Island and P. sapporensis in Hokkaido constitute the same biological species.
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Tomohide Yasunaga
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
9-12
Published: 2000
Released on J-STAGE: October 31, 2002
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A new species of flower or minute pirate bug, Orius takaii, is described from Okinawa Island, the Ryukyus, Japan. This is the first Japanese representative of the nominotypical subgenus of Orius. The anthocorid was confirmed to be associated with a leguminous vine, Pueraria montana, and can be reared with a bulb mite, Rhizoglyphus robini Claparede.
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Hiroshi Suenaga, Akira Tanaka, Hidemi Kamiwada, Takahiro Kamikado, Nao ...
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
13-20
Published: 2000
Released on J-STAGE: October 31, 2002
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Two mass-reared strains of the melon fly, Bactrocera cucurbitae (Coquillett), showed contrasting oviposition patterns throughout a period of long-term culture. The two strains, established in 1980 (old strain) and 1985 (new strain), were maintained in a sterile insect technique project in Kagoshima Prefecture, Japan. During the first several generations of small-scale rearing of the two strains, selection for increased production efficiency was applied. As a result, an early-reproduction trait developed more rapidly in the new strain than in the old strain. After the selection was ceased, an early-reproduction trait developed in the old strain for 25 generations of large-scale mass rearing; there was no further development of the early-reproduction trait in the new strain. The result obtained with two-way selection for age at reproduction suggested that the new strain had been nearly at the selection limit for early reproduction at the beginning of mass rearing. The following two rearing conditions may be responsible for the observed differences in oviposition patterns of the two strains: differences in the selection regimes during the small-scale rearing and differences in the egg-collection methods used in the subsequent course of mass rearing of the strains.
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Yoshio Yamauchi, Jared Ragland, Hideaki Maekawa, Ryoichi Sato, Kunikat ...
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
21-26
Published: 2000
Released on J-STAGE: October 31, 2002
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The cDNA and deduced amino acid sequence for apolipophorin-III from the sweet potato hornworm, Agrius convolvuli, have been determined. The degree of sequence identity of apolipophorin-III between A. convolvuli and the tobacco hornworm, Manduca sexta, is quite high. The amino acid sequence from A. convolvuli also showed high similarity to the sequence of apolipophorin-III of four other Lepidopterans, Bombyx mori, Bombyx mandarina, Galleria mellonella and Spodoptera litura. The high level of cDNA and amino acid sequence identity between A. convolvuli and M. sexta indicates a relatively close phylogenetic relationship with respect to the apolipophorin-III gene.
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Mikio Yoshiyama, Kiyoshi Kimura, Hiroshi Honda
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
27-30
Published: 2000
Released on J-STAGE: October 31, 2002
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A method for microinjection was developed for the housefly, Musca domestica. Chorion membranes of freshly laid eggs were first removed with sodium hypochlorite (NaOCl). Dechorionated eggs were placed on double-sided Scotch tape, desiccated and covered with Halocarbon oil (Sigma). Posterior ends of the eggs were pierced with a fine glass needle for microinjection. Injected eggs were incubated at 25°C until hatching. Eggs dechorionated approximately 40 min after oviposition showed the highest hatching rate. Green food dye and suspended plasmid DNA constructs, included in the phosphate buffer, showed no harmful effects on embryonic development. Using the above procedure, an average of 75.0% of injected eggs survived to the first larval stadium. The technique described herein can be used for microinjection of various substances into the housefly.
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Yiping Zheng, Toyoshi Yoshiga, Sumio Tojo
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
31-39
Published: 2000
Released on J-STAGE: October 31, 2002
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Three storage proteins, hexamerins of 80-90 kDa subunits, have been purified and characterized from the common cutworm, Spodoptera litura. We have cloned the cDNAs of these storage proteins by immunoscreening and rapid amplification of cDNA ends (RACE). The deduced amino acid sequence of SL-1, a basic protein containing 7.7% methionine showed 82.3 and 68.4% identities to the Trichoplusia ni basic juvenile hormone-suppressible storage protein (8.4% methionine) and to the Bombyx mori methionine-rich storage protein (11.8% methionine), respectively. The amino acid sequences of α and β subunits with ca 4% methionine of SL-2, another basic protein, were 84% identical to that of T. ni basic juvenile hormone-suppressible storage protein with moderate methionine content (5.3%), but showed only 45% identity to SL-1. SL-3, an arylphorin was very similar (54-63% identity) to known other arylphorins, but differed considerably (31-35% identity) from SL-1 and SL-2 in their amino acid alignments. The most parsimonious tree obtained by systematic analyses of the sequence alignments of 16 lepidopteran storage proteins demonstrated that three storage proteins of S. litura are clustered into three sister groups, although they share extensive similarities throughout the alignment.
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Takashi Noda
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
41-44
Published: 2000
Released on J-STAGE: October 31, 2002
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The presense of diploid males and a sex determination system in Diadegma semiclausum, a larval parasitoid of Plutella xylostella, was examined by using an allozyme as a genetic marker. Among six enzymes investigated, only phosphoglucomutase (PGM) was apparently polymorphic. Two discrete bands were detected on electrophoretic banding patterns of PGM, indicating PGM was a monomer with two alleles on one locus. After establishing pure lines of each PGM allele, the heterozygous females were allowed to mate with their sons to examine the occurrence rate of diploid males in their progenies. Thus the numbers of diploid males identified did not differ significantly from those expected from the single-locus complementary sex determination (CSD). Inbreeding and the subsequent emergence of diploid males could partly account for the male biased sex ratio in the laboratory culture of D. semiclausum.
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Yoshifumi Hashimoto, Kana Hayashi, Tohru Hayakawa, Yasumasa Ueno, Ei-i ...
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
45-51
Published: 2000
Released on J-STAGE: October 31, 2002
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A plasmid library of restriction DNA fragments of a Plutella xylostella granulovirus (PxGV) was constructed, which covered all 9 EcoRI and all 19 HindIII fragments, and 18 of 20 PstI fragments. Restriction endonuclease analysis and DNA-DNA hybridization analysis of the cloned viral DNA fragments in the library and the restricted viral DNA fragments were carried out for construction of a physical map of PxGV DNA for ApaI, BamHI, BglII, EcoRI, HindIII, KpnI, PstI, SacII, XbaI and XhoI. The size of PxGV genome was estimated to be 102.2 kb. Location of the left-most DNA fragment on the physical map that contained granulin gene was determined by hybridization using a DNA probe of granulin gene of Trichoplusia ni granulovirus. Four homologous regions interspersed on the genome were also determined by DNA-DNA hybridization analysis.
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Osamu Saito
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
53-61
Published: 2000
Released on J-STAGE: October 31, 2002
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The reproductive development of the cotton bollworm moth, Helicoverpa armigera (Hübner), was observed, and flight activity of the moth was measured by actograph. The development of the moth ovary reached the vitellogenesis stage when the moths were 2 days old, and almost all of the moths copulated when they were 3 days old. The daily rhythms of flight activity of the uncopulated moths showed two peaks, one at the beginning and the other in the second half of the scotophase. There were no changes in the daily rhythms of flight activity of copulated males, whereas copulated females had one peak at the beginning of the scotophase. The flight activity of uncopulated cotton bollworm moths increased daily from the time of eclosion, reaching a peak at 3-4 days old, and then gradually reduced. The flight activity of females copulated at 3 days old was low at 4 days old, and then progressively decreased thereafter. The flight activity of copulated males was also low at 4 days old, but the activity levels recovered thereafter. Thus, it appears that the flight activity of the cotton bollworm changes will both age and copulation status.
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Yoshichika Kakei, Koji Tsuchida
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
63-67
Published: 2000
Released on J-STAGE: October 31, 2002
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We examined the effect of relative humidity on mortality during the pupal stage (prepupa and pupa) of Thrips palmi (Thysanoptera: Thripidae) under laboratory conditions. Mortality from the prepupal stage to adulthood decreased with increasing relative humidity. We compared the mortalities under 3 experimental treatments (control; upperside treatment, prepupae were released on filter paper; underside treatment, prepupae were covered with filter paper) at various relative humidities (58, 78, 82, 86, 88, 93 and 98%). The mortality under every treatment at 58% relative humidity was 100%. Except at 58 and 93% relative humidities, the mortalities under the underside treatment were lower than the other treatments. Differences in mortality among all three treatments were found at 82 and 86% relative humidities. At 88, 93 and 98% relative humidities, however, no differences in mortality among the three treatments were found. Logistic regression analysis revealed that both humidity and underside treatment had significant negative effects on mortality. Individuals released in the upperside treatment moved at higher rates within a day from the release than those in the underside treatment.
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Vic Casimero, Ritsuko Tsukuda, Fusao Nakasuji, Kenji Fujisaki
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
69-74
Published: 2000
Released on J-STAGE: October 31, 2002
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This study examined the influence of seven natural diets (cotton boll, cotton leaf, okra fruit, soybean seed, tomato fruit, tomato leaf, and corn kernel) and an artificial diet (Insecta LF) on the larval survival rate, larval duration, frequency of larval stadium types and pupal weight in Helicoverpa armigera. On most diets, the survival rate was notably lower in the early larval stage compared to the late one. The percentage of larvae that survived from the 1st-stadium to the end of the larval stage was highest on okra fruit and Insecta LF (>60%). Less than 60% of the larvae fed on the other diets completed their larval period. The mean larval period was significantly shorter for individuals reared on plant fruits or seeds as well as on Insecta LF than for those reared on plant leaves. The shortest larval duration was recorded on cotton boll while the longest was seen on cotton leaf. The number of larval stadia ranged from 5 to 6 on cotton boll, soybean seed, corn kernel and Insecta LF, 5 to 7 on okra and tomato fruits, and 6 to 7 on cotton and tomato leaves. The five-stadium type was dominant on cotton boll, okra fruit, corn kernel and Insecta LF, while the 6-stadium type was common on soybean seed, tomato fruit, cotton leaf and tomato leaf. Mean pupal weight was greatest in individuals fed on Insecta LF and least in those fed on tomato leaf.
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Tomonari Watanabe, Koichi Tanaka, Hiroya Higuchi, Kenji Miyamoto, Toru ...
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
75-79
Published: 2000
Released on J-STAGE: October 31, 2002
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We investigated the emergence of the overwintering apple snail, Pomacea canaliculata, from paddy soil after irrigation in a rice paddy in Kumamoto Prefecture, Japan. Prior to irrigation, densities of the snails, which were estimated by examining soil samples from the paddy, were 1.8/m
2 and 10.0/m
2 for live and dead snails, respectively. The proportion of live snails was 0.153, which may represent the survival rate throughout the overwintering period. After irrigation, we surveyed the snails emerging in 12 enclosures (pens) of 2 m×8 m constructed in the paddy. A mean of 27.8 snails per pen was found within the first five days after irrigation, and 3.5 per pen were captured in the subsequent 16 days. Thus, most of the snails emerged rapidly, within five days after irrigation; this period of emergence is far shorter than past records. The shell height of live snails collected after irrigation ranged from 4.9 to 25.8 mm, with a mean of 11.5 mm, which was significantly larger than that of dead snails, suggesting a higher mortality of smaller snails during the overwintering period.
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Yoshihisa Abe, Takashi Nakamura, Hiromitsu Inoue
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
81-85
Published: 2000
Released on J-STAGE: October 31, 2002
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The host plant preference of the Japanese population of Epilachna varivestis Mulsant (Coleoptera: Coccinellidae) as well as the host suitability for the beetle were studied at 25°C, under a 15L:9D photoregime. Three Fabaceae crops: Vigna angularis (L.), Phaseolus vulgaris L. and Vicia faba L., and two Fabaceae weeds: Pueraria lobata (Willd.) and Lespedeza bicolor Turcz., were examined. None of the 1st stadium larvae of E. varivestis fed on L. bicolor. The survivorship of larvae was low on P. lobata, but some adults fed on this plant. Thus, P. lobata may be used as a temporary resource by E. varivestis before this beetle colonizes more suitable plants. Neither adults nor 1st stadium larvae of E. varivestis fed on V. faba, but almost all the beetles examined completed development and reproduced on V. angularis and P. vulgaris. Therefore, E. varivestis has the potential to become an economic pest of V. angularis, although this bean, at present, is not as suitable as P. vulgaris for larval development and reproduction.
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Kaori Shiojiri, Junji Takabayashi, Syuichi Yano, Akio Takafuji
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
87-92
Published: 2000
Released on J-STAGE: October 31, 2002
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We observed the flight response of Cotesia plutellae and C. glomerata, which respectively parasitize Plutella xylostella and Pieris rapae, to crucifer plants. C. plutellae preferred the cabbage and Japanese radish plants infested by the hosts to uninfested, artificially damaged and nonhost (P. rapae)-infested plants. C. glomerata preferred host-infested cabbage plants to uninfested plants. However, C. glomerata showed an equal preference for host-infested plants and nonhost (P. xylostella)-infested or artificially damaged plants. In a comparison between plants infested by both herbivore species and those infested by the respective host larvae, C. plutellae preferred the host-infested plants, whereas C. glomerata preferred the plants infested by both species. These results indicate that (1) C. plutellae shows a specific response toward the host-plant complex, whereas C. glomerata does not, and (2) the presence of the nonhost affects the specificity of the response of the wasps toward the host-plant complex.
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Takahiro Hosokawa, Nobuhiko Suzuki
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
93-99
Published: 2000
Released on J-STAGE: October 31, 2002
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In the stink bug, Megacopta punctatissima, which forms mating aggregations, male mating behaviors and the copulatory success of males were examined in experimental populations with 4 different sex ratios. In the male-biased sex ratio, more males tended to stay in “copulatory aggregations” including at least a mating pair rather than in “non-copulatory aggregations” including no mating pair, despite a scarcity of non-copulating females in such aggregations. However, when copulating females were included, there were more females in the copulatory aggregations than those in the non-copulatory aggregations. Therefore, the results appear to suggest that males also regarded copulating females as potential mates. Males which had immigrated to an aggregation showed a higher copulatory success than resident males in the aggregation at a male-biased sex ratio. Moreover, males showed a large variation in mating success, and those which had a higher mating success tended to stay in aggregations of female-biased sex ratios. These results suggest that females may choose their mates in mating aggregations, and that the choice may influence male mating success more acutely in a male-biased sex ratio.
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Kiyomitsu Ito, Tadafumi Nakata
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
101-105
Published: 2000
Released on J-STAGE: October 31, 2002
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The critical photoperiod for short-day induced diapause was examined in eight different populations of Orius sauteri collected from northern Japan (36.0°N-45.4°N). Five out of six populations from Hokkaido had steep long-day type photoperiodic responses, i.e., almost all females grown under 14L-10D or shorter photoregime entered reproductive diapause and as little as a 1 h transition of photoperiod around the critical photoperiod drastically changed the diapause response. The curves of the photoperiodic response were relatively gentle in the most southern population of the Hokkaido and two northern Honshu populations. In particular, some females of the Tsukuba population (36.0°N) even laid eggs under such short daylengths as 11L-13D or 12L-12D. The critical photoperiod was longer in the populations from higher latitudes and shorter in those from lower latitudes, i.e., a clinal relationship was observed. The benefit of introduction of the southern populations to Hokkaido was discussed from the viewpoint of diapause. The advantages of the use of non-diapause strains selected from southern populations such as the Tsukuba population were also considered.
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Shohei Okuno, Madoka Nakai, Nobuyuki Seino, Tsuyoshi Hiraoka, Yasuhisa ...
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
107-113
Published: 2000
Released on J-STAGE: October 31, 2002
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Virion-free plasma from larvae of the armyworm, Pseudaletia separata, infected with an entomopoxvirus (PsEPV), adversely affects the embryonic and larval stages of the gregarious braconid endoparasitoid, Cotesia kariyai. We investigated the toxicity of virion-free plasma from PsEPV-infected P. separata larvae against C. kariyai embryos and larvae cultured in vitro. Parasitoid larvae collected from host larvae were individually transferred into plastic Petri dishes with IPL-41 medium and culture at 25°C for 7 d. The development of C. kariyai larvae was adversely affected when virion-free plasma was added to IPL-41 medium, even up to a dilution of 128. The mortality of in vitro-cultured parasitoid larvae decreased with increases in the concentration of virion-free plasma added to the medium. The parasitoid larvae became less susceptible to the lethal factor as the larval stage increased. Parasitoid larvae culture in IPL-41 medium added to virion-free plasma developed little if at all, and shrank and died 2 to 6 d after the start of culture, regardless of the larval stage of the parasitoid. In dead parasitoid larvae, the tissue receded from the cuticle and organs lost their organization and cellular integrity. Embryos cultured in IPL-41 medium containing virion-free plasma never progressed beyond the egg stage, and somatic tissues lost their organization. On the other hand, embryos cultured in IPL-41 medium containing normal plasma developed to the first stadium.
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Junji Takabayashi, Yoshibumi Sato, Shuichi Yano, Naota Ohsaki
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
115-118
Published: 2000
Released on J-STAGE: October 31, 2002
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We found that Pieris rapae larvae secreted oily droplets from the dorsal setae. By using GC-MS analysis, we identified palmitic acid and stearic acid as the major components in the secretion. We already reported that Cotesia glomerata, a parasitoid of P. rapae larvae, showed characteristic antennation to palmitic acid and stearic acid in the host-infested edge of the leaf. Based on our previous reports together with the result of this study, we inferred that the two fatty acids in the droplets were used by C. glomerata in her host searching.
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Hajime Ono, Ritsuo Nishida, Yasumasa Kuwahara
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
119-123
Published: 2000
Released on J-STAGE: October 31, 2002
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The oviposition response of a swallowtail butterfly, Papilio bianor, was elicited by a methanolic extract from leaves of its host plant Orixa japonica (Rutaceae). Reverse phase ODS column chromatography of a water soluble layer separated two active fractions, eluted with 1% acetic acid in water and 40% methanol +1% acetic acid in water. A major active stimulant in the latter eluate was isolated and identified as (−)-4-(E)-caffeoyl-L-threonic acid. This compound was found to be active alone (43% oviposition response at 0.1 g leaf equivalent per 10 cm
2 filter paper) and there was no significant synergistic effect of the compound on other active fractions. Hydroxycinnamic acid derivatives appear to be utilized widely as oviposition cues among the Papilionidae.
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Yukio Ishikawa, Tôru Kanke
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
125-130
Published: 2000
Released on J-STAGE: October 31, 2002
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Barley seedlings strongly deterred feeding of the migratory locust Locusta migratoria. Analysis of feeding-related behavior revealed that approach to barley seedlings and palpation occurred just as with palatable plants, but rejection of the plant occurred immediately after biting. Excision of the maxillary and labial palps had no effect on the rejection of barley seedlings, and feeding of palatable plants occurred as with intact insects. Removal of compounds on the surface of the barley leaves also had no effect, while ethanol extraction of the leaves diminished the deterrence of the barley seedlings. These results indicated that feeding deterrent(s) are localized inside the seedlings. An ethanol extract of barley seedlings exhibited strong deterrence in a feeding assay using a piece of sucrose-impregnated filter paper as the feeding substrate. Fractionation of the ethanol extract revealed that the strongest feeding deterrence was observed with the basic fraction, which contains alkaloids such as gramine. The other fractions also showed weak feeding deterrence. A crude alkaloid extract equivalent to 100 mg of barley leaf inhibited feeding of the locusts by 90%.
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Chiaki Fujiwara, Junji Takabayashi, Shuichi Yano
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
131-136
Published: 2000
Released on J-STAGE: October 31, 2002
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We measured the parasitization rates of Mythimna separata by a parasitoid, Cotesia kariyai, in a climate room on one species each of corn plant, kidney bean and Japanese radish plant. The trend of parasitization by wasps was corn>kidney bean>Japanese radish. In a cage, C. kariyai had greater olfactory responses to leaves (of corn, kidney bean, and Japanese radish) infested by the host larvae than to uninfested leaves. When we compared infested leaves using pairs of plant species, the wasps showed preference in this order: corn>kidney bean>Japanese radish. From GC-MS analysis, we found qualitative and quantitative differences in the blend of volatiles emitted from infested leaves of the three plant species. Such differences were considered to be one of the factors affecting the parasitization rates.
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Makoto Abe, Kazuhiro Matsuda, Yoshio Tamaki
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
137-142
Published: 2000
Released on J-STAGE: October 31, 2002
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Feeding responses to four cucurbitacins (B, E, I and E-glucoside) were investigated in three cucurbitaceous feeding leaf beetles, Aulacophora femoralis (Motschulsky), A. lewisii Baly and A. nigripennis Motschulsky by filter paper assay. A. femoralis and A. lewisii were strongly stimulated to feed by four cucurbitacins, and A. nigripennis was weakly stimulated to feed by cucurbitacin B at a concentration of only 0.01 mg/ml. A. nigripennis showed no significant feeding stimulant activity to cucurbitacins by a leaf disk assay. These results indicate that not all cucurbitaceous feeding beetle species are strongly stimulated to feed by cucurbitacins.
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Makoto Abe, Kazuhiro Matsuda
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
143-149
Published: 2000
Released on J-STAGE: October 31, 2002
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Cucurbitaceous feeding beetle species, Aulacophora femoralis, A. nigripennis, Epilachna admirabilis and E. boisduvali seldom attack Momordica charantia. The methanol extract of M. charantia leaves strongly deterred four beetle species from feeding. The methanol extract was partitioned between organic solvent and water, and the chloroform fraction, which showed a strong feeding deterrency, was obtained. The chloroform fraction was chromatographed with a silica gel column, and momordicines I and II were isolated. A. nigripennis was strongly deterred from feeding by momordicines I and II at lower concentrations than contained in M. charantia leaves. A. femoralis was deterred from feeding by momordicine II at a high concentration. The feeding of E. admirabilis and E. boisduvali was not affected by momordicines I and II alone. However, E. admirabilis and E. boisduvali were strongly deterred from feeding by mixtures of momordicines I and II, and momordicine II and other components.
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Satoshi Toda, Minoru Miyazaki, Mh. Osakabe, Shinkichi Komazaki
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
151-154
Published: 2000
Released on J-STAGE: October 31, 2002
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Torymus sinensis, an introduced parasitoid of Dryocosmus kuriphilus, was found to be present in the Oki islands though it had never been released there. To investigate the seasonal occurrence of two parasitoid wasps, T. sinensis and Torymus beneficus, and their hybrids, we collected 611 withered galls formed by D. kuriphilus in March 1996. Ninety-three females and 182 males of Torymus emerged from the galls. We separated species by the morphology and genotype of the malic enzyme (ME). Both parasitoids were found and T. sinensis was dominant. Seven females showed 5 bands of ME migrating between the S and F bands and were hybrids of T. sinensis with early-emerging T. beneficus. Only 8% of females were hybrids. Hybridization seemed to occur at low frequency in the field. Oki’s T. sinensis is considered to have been accidentally introduced long before our investigation and was classified into a Chinese ecotype judging from their eclosion period.
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Hiroshi Kajita
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
155-162
Published: 2000
Released on J-STAGE: October 31, 2002
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To determine the geographical distribution and composition of parasitoid species from Trialeurodes vaporariorum and the Bemisia tabaci-complex (B. tabaci and B. argentifolii), parasitized whiteflies were collected at different sites in Japan and parasitoids were reared for adult emergence. Amitus sp., Encarsia citri, E. formosa, E. japonica, E. lutea, E. transvena, Encarsia sp., Eretmocerus sp. and Syrphophagus sp. were reared from Trialeurodes vaporariorum sampled at 125 sites from 1977 to 1998. Amitus sp., E. azimi, E. citri, E. formosa, E. japonica, E. lutea, E. transvena and Eretmocerus sp. were reared from a B. tabaci-complex sampled at 36 sites from 1990 to 1998. The indigenous species E. japonica and E. transvena are widely distributed in Japan and are predominant parasitoids of T. vaporariorum and the B. tabaci-complex. The introduced parasitoid E. formosa has recently been found at many sites near greenhouses in which it has been used commercially by seasonal inoculative release to control T. vaporariorum and B. argentifolii. This is because some E. formosa leave the greenhouses to parasitize whiteflies in the field. Single species composition per site was dominant for T. vaporariorum and not numerous for the B. tabaci-complex. At the sites containing two or three parasitoid species, E. formosa was attacked frequently by E. japonica and E. transvena which are facultative heteronomous hyperparasitoids. In addition, male Syrphophagus sp. was also a hyperparasitoid of E. formosa.
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Tohru Hayakawa, Ei-ichi Shimojo, Masashi Mori, Masanori Kaido, Iwao Fu ...
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
163-170
Published: 2000
Released on J-STAGE: October 31, 2002
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A baculovirus virulence-associated protein, enhancin, was engineered for production in a baculovirus-insect cell expression system and used for transformation of tobacco plants. A recombinant Autographa californica nucleopolyhedrovirus (AcNPV) with the enhancin gene from Trichoplusia ni granulovirus, AcEnh26, was propagated in Sf9 cells. The infected cultured cells combined with either AcNPV occlusion bodies (OBs) or Spodoptera exigua NPV (SeNPV) OBs were fed to 3rd stadium larvae of S. exigua. Feeding larvae with AcEnh26-infected cells resulted in a 21-fold and 10-fold enhancement of infection by AcNPV and SeNPV, respectively, compared to controls. When a similar feeding assay was performed with engineered tobacco plants, a 10-fold enhancement of AcNPV infection was observed, but a marked enhancement of SeNPV infection was not observed. Thus, the engineering and expression of the baculovirus enhancin gene in homologous and heterologous organisms allowed us to analyze its effects on NPV infection of larvae which demonstrated its viral enhancement function.
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Tsutomu Saito, Hiroshi Hama
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
171-175
Published: 2000
Released on J-STAGE: October 31, 2002
JOURNAL
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Carboxylesterase isozymes responsible for organophosphate resistance in the cotton aphid, Aphis gossypii Glover, were evaluated by inhibitory experiments on isoelectric focused bands. Differences in the carboxylesterase band patterns were detected between organophosphate-susceptible and resistant clones, and the activity of all bands was equally inhibited by fenitroxon in both clones. The activity was also inhibited by carbaryl, methomyl and K2 (2-phenoxy-4H-1,3,2-benzodioxaphosphorin 2-oxide) in a resistant clone. Fenitroxon showed the highest inhibitory activity. On the other hand, in the peach-potato aphid, Myzus persicae (Sulz.), used as a comparative aphid species, no difference was detected in the carboxylesterase band patterns between organophosphate-susceptible and resistant clones. A single band, however, showed different activity between the clones. The band, whose activity was inhibited by fenitroxon, may be the isozyme responsible for insecticide resistance in M. persicae. These results indicate that all carboxylesterase isozymes, but not the particular isozyme in M. persicae, are related to organophosphate resistance, and that overall enzyme activity determines the degree of resistance in A. gossypii.
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Koichi Tanaka, Shozo Endo, Hikaru Kazano
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
177-187
Published: 2000
Released on J-STAGE: October 31, 2002
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The toxicity of nine insecticides to predators of rice planthoppers was examined with first instars of four spider species, i.e. Pardosa pseudoannulata, Tetragnatha maxillosa, Ummeliata insecticeps and Gnathonarium exsiccatum, and females of the mirid bug Cyrtorhinus lividipennis and the dryinid wasp Haplogonatopus apicalis, by dipping the test arthropods into insecticide solution. Deltamethrin was the most toxic to the spiders, with LC
50 at 0.033 to 1.1 ppm, followed by ethofenprox. The results indicate that the spiders are susceptible to synthetic pyrethroids. Insecticide susceptibilities of the spiders varied among species. T. maxillosa was more susceptible to seven insecticides, particularly to diazinon, than the other spiders, but P. pseudoannulata was more susceptible to phenthoate and carbaryl than T. maxillosa. Many insecticides, particularly phenthoate, imidacloprid and deltamethrin, were toxic to C. lividipennis. All insecticides tested were toxic to H. apicalis. We also evaluated the effect of insecticides on the spiders and C. lividipennis in paddy fields. Deltamethrin had a destructive effect on the spider populations and may have induced a resurgence of the Nilaparvata lugens population. Phenthoate reduced the abundance of lycosid spiders, and ethofenprox reduced the abundance of Tetragnatha. The C. lividipennis abundance decreased to a low level in all insecticide-treated plots except those treated by buprofezin.
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Abdul Razaq, Nobuo Ohbayashi, Masaya Shiraishi, Hironori Ono, Masakazu ...
Article type: Others
Subject area: Others
2000 Volume 35 Issue 1 Pages
189-198
Published: 2000
Released on J-STAGE: October 31, 2002
JOURNAL
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A comparative study of the mouthparts of Panonychus citri (McGregor) and Agistemus terminalis (Quayle) were conducted under scanning electron microscope. In P. citri, the palpus is five segmented and irregularly striated. The palpotarsus has three setae, three sensory organs and one smooth surfaced palpotarsal eupathidial spinneret. The palpotibia has comparatively small claws. The stylophore is comprised of irregularly striated basal and horizontally striated distal segments. The stylets are smoothly surfaced and originate from the ventral portion of fixed digits. The rostrum has an elevated lip of rostral gutter on its dorsal surface and a membranous flap on the ventral and lateral sides. The cheliceral stylets are cylindrically concave and reveal a rod-shaped food channel in the mesal region. While in A. terminalis, the palpus is also five segmented, a portion of the second segment is striated and the others are smoothly surfaced. The palpotarsus has a cylindrical and roughly surfaced sensory organ which exhibits a branched slender trifid sensillum at the apex. The palpotibia has bigger sharp claws, thicker at the base and roughly surfaced. The stylophore consists of a membranous basal and smoothly surfaced distal segments. The rostrum has a membranous overlap on the dorsal surface extending up to the rostral cavity.
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