Applied Entomology and Zoology

Regular Papers

Expression efficiency of a scorpion neurotoxin, AaHIT, using baculovirus in insect cells

Kiyoko Taniai, Ahmet B. Inceoglu, Bruce D. Hammock

Article type: Regular Paper
Subject area: [not specified]
2002 Volume 37 Issue 2 Pages 225-232
Published: 2002
Released on J-STAGE: April 25, 2003

DOIhttps://doi.org/10.1303/aez.2002.225

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Insect-selective neurotoxins are useful agents for developing recombinant baculoviral insecticides. AaHIT, one such toxin, was expressed in AcMNPV and had a dramatic effect on pest insects. However, the toxin production was relatively low. In order to identify reasons for the low production of recombinant AaHIT (rAaHIT) in insect cells, we analyzed the expression efficiency using Northern blotting, enzyme-linked immunosorbent assay, Western blotting, and a bioassay using Sarcophaga falculata larvae. The levels of rAaHIT mRNA and protein in Sf21 cells were comparable with those of another secreted protein, recombinant juvenile hormone esterase (rJHE), which was expressed in the same baculovirus system. However, the secretion efficacy of rAaHIT was significantly lower than that of rJHE. In addition, the toxic activity in the medium was approximately 1% of the total secreted rAaHIT. Western blot analyses suggested that rAaHIT aggregated and accumulated in cells. We attempted to increase the amount of soluble rAaHIT in cells using a co-expressed chaperonin, BiP. Although co-expressed BiP apparently increased the amount of soluble rAaHIT in cells, no improvement of active toxin production in the medium was detected. These results suggest that secretion and folding of rAaHIT are insufficient in insect cells.

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The effect of sonicating Pasteuria penetrans spores on their infection in root-knot nematode Meloidogyne spp. (Tylenchida: Meloidogynidae)

Yukio Orui

Article type: Regular Paper
Subject area: [not specified]
2002 Volume 37 Issue 2 Pages 233-235
Published: 2002
Released on J-STAGE: April 25, 2003

DOIhttps://doi.org/10.1303/aez.2002.233

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The effect of sonicating Pasteuria penetrans spores on their infection in the root-knot nematodes Meloidogyne spp. was investigated using P. penetrans isolates MAP from M. arenaria and MHP from M. hapla. The spores of MAP and MHP taken from adult females were suspended in sterile water, and stored for two months at 5°C. Then, the spores were sonicated for 5, 15, and 30 min. The infection rates of sonicated MAP and MHP spores in females were 2.0–2.3 times and 1.5–3.0 times as high as the respective non-sonicated treatments. After sonication, the infectivity to Meloidogyne females for both MAP and MHP spores was remarkably enhanced.

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Parasitoids (Hymenoptera: Braconidae, Aphidiinae; Aphelinidae) of four principal pest aphids (Homoptera: Aphididae) on greenhouse vegetable crops in Japan

Hajimu Takada

Article type: Regular Paper
Subject area: [not specified]
2002 Volume 37 Issue 2 Pages 237-249
Published: 2002
Released on J-STAGE: April 25, 2003

DOIhttps://doi.org/10.1303/aez.2002.237

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Aphidiine and aphelinid parasitoids of four principal pest aphids on greenhouse vegetable crops in Japan, Aphis gossypii, Myzus persicae, Macrosiphum euphorbiae and Aulacorthum solani, were surveyed to find native parasitoids that would be useful as biological control agents. A total of 19 species (Aphidiinae: 13 species in 7 genera, Aphelinidae: 6 Aphelinus species) were confirmed as parasitoids of the four pest aphids from field collection and breeding experiments. Of these, six species (Lysiphlebus fabarum and 5 Aphelinus species) were new to Japan. In total, 145 tritrophic (parasitoid–host aphid–plant) relationships are reported. The principal aphidiine parasitoids were Lysiphlebus japonicus and Binodoxys communis on A. gossypii, Aphidius gifuensis and Diaeretiella rapae on M. persicae, and A. gifuensis on A. solani. There were no predominant species among the parasitoid spectrum of M. euphorbiae in Japan. Aphelinus gossypii, A. varipes, A. albipodus and A. asychis showed a high degree of suitability for Aphis gossypii, Aphis gossypii and M. persicae, M. persicae and M. euphorbiae, and all four principal pest aphids, respectively. A key to the parasitoid species associated with the four pest aphids in Japan is provided. The potential using the native parasitoids as biological control agents against the four pest aphids is discussed.

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Method in sex discrimination in the mango pulp weevil Sternochetus frigidus (Fabr.) (Coleoptera: Curculionidae)

Louella Rowena Allera De Jesus, Satoshi Nojima, Jose R. Medina, Kanju ...

Article type: Regular Paper
Subject area: [not specified]
2002 Volume 37 Issue 2 Pages 251-255
Published: 2002
Released on J-STAGE: April 25, 2003

DOIhttps://doi.org/10.1303/aez.2002.251

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We describe a simple method for sexing Sternochetus frigidus (Fabr.) using a stereomicroscope to view the dorsum of the terminal abdominal segment. In the male, clipped wings exposed distinctly truncate penultimate segments, whereas in the female, the terminal tergite tapered posteriorly.

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Temporal differences in mating behavior between rice- and water-oats-populations of the striped stem borer, Chilo suppressalis (Walker) (Lepidoptera: Crambidae)

I Made Samudra, Kaoru Emura, Sugihiko Hoshizaki, Yukio Ishikawa, Sadah ...

Article type: Regular Paper
Subject area: [not specified]
2002 Volume 37 Issue 2 Pages 257-262
Published: 2002
Released on J-STAGE: April 25, 2003

DOIhttps://doi.org/10.1303/aez.2002.257

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Rice-feeding and water-oats-feeding populations of Chilo suppressalis usually occur over areas around paddy fields in Japan. Laboratory observations showed temporal differences in mating and female calling between the populations. The rice-population was sexually active in the first half of the scotophase whereas the water-oats-population was sexually active in the second half of the scotophase. Under a no-choice condition in the laboratory, adults of the rice- and water-oats-populations could hybridize in both reciprocal crosses. However, mating frequency was significantly lower in crossings between females of the rice-population and males of the water-oats-population than in the opposite crosses. The peak time of mating in the F1 generation was intermediate between the times of their parental populations. Similar patterns of mating time were observed in the F2 generation. These results indicate that the time of mating in C. suppressalis is genetically controlled, most likely by a polygenic system.

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Density dynamics of the entomopathogenic fungus, Beauveria bassiana Vuillemin (Deuteromycotina: Hyphomycetes) introduced into forest soil, and its influence on other soil microorganisms

Mitsuaki Shimazu, Noritoshi Maehara, Hiroki Sato

Article type: Regular Paper
Subject area: [not specified]
2002 Volume 37 Issue 2 Pages 263-269
Published: 2002
Released on J-STAGE: April 25, 2003

DOIhttps://doi.org/10.1303/aez.2002.263

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Beauveria bassiana conidia were mixed into the forest soil, and the density dynamics of soil microorganisms were investigated using selective media to clarify the impact of B. bassiana application on them. The density of bacteria was between 1×10⁶ and 10⁸ CFU/g, and that of actinomycetes was around 1×10⁶ to 10⁷ CFU/g regardless of the addition of B. bassiana. Densities of general fungi and of B. bassiana in the non-treatment plot were always approximately 1×10⁵ CFU/g and 1×10² CFU/g, respectively. On the other hand, densities of both general fungi and B. bassiana in the treatment plot increased to 3 to 5×10⁷ CFU/g immediately after the mixing of B. bassiana. Densities gradually decreased to 1/10 the density after 12 months. Microscopic observations revealed that B. bassiana conidia do not germinate in non-sterilized soil, but they do germinate in sterilized soil. Densities of fungi other than B. bassiana could not be measured in the treatment plot. However, they were not thought to be affected by mixing of B. bassiana, because the metabolism of B. bassiana seemed to be very inert.

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Host plant resistance in Japanese chrysanthemums against Frankliniella occidentalis (Thysanoptera: Thripidae) during the non-flowering stage

Izumi Ohta

Article type: Regular Paper
Subject area: [not specified]
2002 Volume 37 Issue 2 Pages 271-277
Published: 2002
Released on J-STAGE: April 25, 2003

DOIhttps://doi.org/10.1303/aez.2002.271

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Leaf damage caused by Frankliniella occidentalis and its population growth were investigated with the vegetative plants of two Japanese chrysanthemum cultivars, Yuki-no-izumi and Kan-komichi in greenhouses. Significant differences were found in the levels of leaf damage and thrips population growth between the two cultivars. On Kan-komichi, which had significantly less damage to leaves, the size of the thrips population was smaller than that on Yuki-no-izumi, indicating a clear difference in host plant resistance to F. occidentalis between the two cultivars. Life history characters of the thrips were individually determined on the two cultivars in a laboratory. Most thrips larvae that fed on the leaves of Kan-komichi died before prepupation. This high mortality can contribute to a higher resistance demonstrated by that cultivar in the greenhouse experiment.

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Radiolabeling of cuticular proteins of the brown-winged green bug, Plautia stali Scott (Hemiptera: Pentatomidae)

Fumio Ihara, Koji Mishiro, Takeru Sato

Article type: Regular Paper
Subject area: [not specified]
2002 Volume 37 Issue 2 Pages 279-283
Published: 2002
Released on J-STAGE: April 25, 2003

DOIhttps://doi.org/10.1303/aez.2002.279

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Fourth-stadium nymphs of the brown-winged green bug, Plautia stali, were orally labeled with [³⁵S]cysteine. We then measured the levels of radioactivity in the fourth- and last-stadia exuvia. Levels of radioactivity in the exuvia increased with increasing doses of [³⁵S]cysteine. The radioactivity levels of labeled exuvia treated with KOH suggested that the [³⁵S]cysteine was incorporated into cuticular proteins. The degradation pattern of labeled exuvia by bovine pancreas protease and crude enzyme solutions prepared from entomopathogenic fungi suggested that radiolabeled exuvium can be used as a substrate for cuticle-degrading enzymes.

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Effects of synthesized tannin on the growth and survival of a generalist herbivorous insect, the common cutworm, Spodoptera litura Fabricius (Lepidoptera: Noctuidae)

Masahiro Nomura, Takao Itioka

Article type: Regular Paper
Subject area: [not specified]
2002 Volume 37 Issue 2 Pages 285-289
Published: 2002
Released on J-STAGE: April 25, 2003

DOIhttps://doi.org/10.1303/aez.2002.285

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We examined the effects of tannin on a generalist herbivorous insect, the common cutworm (Spodoptera litura). The dosage effect was estimated by measuring the growth performance of the cutworm when the larvae were fed artificial diets containing different amounts of synthesized tannin. We used artificial diets to exclude the effects of non-tannin defense mechanisms in plant foliage. Indices of growth performance, number of dead larvae, pupal weight, total feeding amount and length of larval period were obtained. We found that tannin inhibited the growth of the cutworm larvae and that the inhibitory effect was proportional to the amount of tannin ingested. These results support the traditional theory that plant tannin is a defense agent against generalist herbivores, and that its effects are proportional to its concentration in foliage.

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Expression of growth-blocking peptide in Mamestra brassicae (Lepidoptera: Noctuidae) cell lines

Masakuni Narita, Kikuo Iwabuchi, Tsuyoshi Hiraoka

Article type: Regular Paper
Subject area: [not specified]
2002 Volume 37 Issue 2 Pages 291-294
Published: 2002
Released on J-STAGE: April 25, 2003

DOIhttps://doi.org/10.1303/aez.2002.291

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Growth blocking peptide (GBP) is one of the growth regulators in lepidopteran insects. Using RT-PCR, we detected GBP expression in two insect cell lines from Mamestra brassicae, SES-MaBr-4 from the fat body and SES-MaBr-93 from hemocytes. The sizes of the RT-PCR products agreed with the sizes calculated from the GBP cDNA sequence. These findings suggest that GBP is a candidate for an essential growth factor in these insect cell lines.

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Individual rearing of the Japanese mealybug, Planococcus kraunhiae (Kuwana) (Homoptera: Pseudococcidae) on germinated broad bean seeds

Yutaka Narai, Tamotsu Murai

Article type: Regular Paper
Subject area: [not specified]
2002 Volume 37 Issue 2 Pages 295-298
Published: 2002
Released on J-STAGE: April 25, 2003

DOIhttps://doi.org/10.1303/aez.2002.295

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The Japanese mealybug, Planococcus kraunhiae could be reared individually on germinated broad bean seeds as an alternative food source. The developmental period from egg stage to adult oviposition was 65 days at 20°C and 46 days at 24°C. Egg hatchability was higher than 98% at both temperatures. Survival rate from egg stage to adult emergence was 76% at 20°C and 81% at 24°C. The total number of eggs per female was 588 at 20°C and 965 at 24°C. Adult longevity of females at 20°C and 24°C was 32 days and 26 days, respectively. The suitability of germinated broad bean seeds for P. kraunhiae is discussed in comparison with other alternative food sources.

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Resistance to a mating disruptant composed of (Z)-11-tetradecenyl acetate in the smaller tea tortrix, Adoxophyes honmai (Yasuda) (Lepidoptera: Tortricidae)

Fumiaki Mochizuki, Takehiko Fukumoto, Hiroshi Noguchi, Hajime Sugie, T ...

Article type: Regular Paper
Subject area: [not specified]
2002 Volume 37 Issue 2 Pages 299-304
Published: 2002
Released on J-STAGE: April 25, 2003

DOIhttps://doi.org/10.1303/aez.2002.299

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At tea fields in Shimada in Shizuoka Prefecture, a mating disruptant composed of (Z)-11-tetradecenyl acetate (trade name: Hamaki-con) had been used for controlling Adoxophyes honmai (Yasuda) annually since 1983. In 1986, four years after use of the disruptant was initiated, the disruption percentage of pheromone trap catches was 96%, and a high control effect was observed. However, from 1996 to 1998, 14 to 16 years after treatment was started, the percentages became less than 50%. When the disruptant was applied in other tea fields where it had not been previously used, the disruption percentages were over 99%. These results strongly suggest the possibility that a selection pressure caused by continuous use of the disruptant should have caused the low disruption percentage in Shimada. We propose that the phenomenon be termed “resistance” to a mating disruptant composed of (Z)-11-tetradecenyl acetate in A. honmai. When the sex pheromone blend of A. honmai, 63 : 31 : 4 : 2 mixture of (Z)-9-tetradecenyl acetate, (Z)-11-tetradecenyl acetate, (E)-11-tetradecenyl acetate and 10-methyldodecyl acetate (4-component blend), was applied as a disruptant for the “resistance” population, the disruption percentage was 99% and the larval density in the next generation decreased. These results suggest that the 4-component blend is useful as a control tool for the “resistance” population.

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Biotic characteristics in the deltamethrin-susceptible and resistant strains of Culex pipiens pallens (Diptera: Culicidae) in China

Xiulan Li, Lei Ma, Lixin Sun, Changliang Zhu

Article type: Regular Paper
Subject area: [not specified]
2002 Volume 37 Issue 2 Pages 305-308
Published: 2002
Released on J-STAGE: April 25, 2003

DOIhttps://doi.org/10.1303/aez.2002.305

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Culex pipiens pallens was selected with deltamethrin for 12 generations, and the LC₅₀ value rose steadily from 0.040 mg/l to 24.660 mg/l (617 times). The biotic parameters were observed for the deltamethrin-susceptible (SS) and resistant (RR) strains of C. pipiens pallens in the laboratory. In the RR strain, the fecundity, percentage of pupation and emergence decreased by 44.8%, 17.6% and 8.9% respectively; the percentage of scattered eggs increased by 22.5%; the time from hatching to emergence was prolonged by 1.32 days; the weight of female and male adults increased by 0.202 mg and 0.231 mg, respectively; and the life-span of the female and male adults was reduced by 4.13 days and 4.74 days, respectively. The results indicated that deltamethrin resistance of the mosquito was correlated with disadvantages during reproduction.

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Microsatellites in the gypsy moth, Lymantria dispar L. (Lepidoptera: Lymantriidae)

Chiharu Koshio, Miwako Tomishima, Koji Shimizu, Heui-Soo Kim, Osamu Ta ...

Article type: Regular Paper
Subject area: [not specified]
2002 Volume 37 Issue 2 Pages 309-312
Published: 2002
Released on J-STAGE: April 25, 2003

DOIhttps://doi.org/10.1303/aez.2002.309

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Gypsy moth DNA segments containing polymorphic dinucleotide repeats were sought for future studies regarding paternity and sperm precedence. Three microsatellite DNA loci were amplified by three sets of primers. These loci were sufficiently polymorphic to be used for paternity tests. The allele types observed were different among the three local populations.

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Improvement of egg collection method in West Indian sweetpotato weevil, Euscepes postfasciatus (Fairmaire) (Coleoptera: Curculionidae) by feeding on a smaller cubic piece of sweet potato root

Yukio Shimoji, Masaaki Yamagishi

Article type: Regular Paper
Subject area: [not specified]
2002 Volume 37 Issue 2 Pages 313-318
Published: 2002
Released on J-STAGE: April 25, 2003

DOIhttps://doi.org/10.1303/aez.2002.313

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A mass-rearing system is necessary for success in the West Indian sweetpotato weevil, Euscepes postfasciatus, eradication project using the sterile insect technique (SIT). We must establish an efficient egg collection method, because a large number of eggs must be placed on the surface of an artificial diet for mass-rearing of E. postfasciatus. When females of E. postfasciatus were provided smaller cubic pieces of sweet potato root, they fed but were not able to lay eggs in them. As a result, the females stored more mature chorioned oocytes in the ovariole than normal females that were able to feed and lay eggs. When these females were starved, they dropped twice as many fertilized eggs at random after being provided larger cubic pieces of sweet potato root in which it was possible to lay eggs. We discuss application of this female egg-dropping trait to an actual mass-rearing system.

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Effects of host age and size on clutch size and sex ratio of Oomyzus sokolowskii (Hymenoptera: Eulophidae), a larval-pupal parasitoid of Plutella xylostella (Lepidoptera: Yponomeutidae)

Akiko Nakamura, Takashi Noda

Article type: Regular Paper
Subject area: [not specified]
2002 Volume 37 Issue 2 Pages 319-322
Published: 2002
Released on J-STAGE: April 25, 2003

DOIhttps://doi.org/10.1303/aez.2002.319

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We investigated the effects of host age and size on clutch size and sex ratio of Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae). The number of eggs laid (primary clutch size) tended to increase with host age and was significantly larger for the late fourth-stadium larvae than for the second- and third-stadium larvae. The number of wasps that emerged from a host (secondary clutch size) tended to increase with host age and was significantly larger for the late fourth-stadium hosts than for the second-stadium hosts. In the late fourth-stadium hosts, secondary clutch size tended to increase significantly with host size. There were no significant differences in sex ratios among host ages or sizes. Where fewer than 10 wasps emerged from a host, most clutches produced only 1 male; larger clusters tended to produce 2 or more males. This implies that O. sokolowskii may deposit male eggs in the early eggs of a clutch and place the second male eggs in the tenth or later eggs of a clutch. By this mechanism, O. sokolowskii is thought to produce an invariable sex ratio regardless of clutch size.

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Analysis in the course of polydnavirus replication in ovarian calyx cells of the parasitoid wasp, Cotesia kariyai (Hymenoptera: Braconidae)

Kohjiro Tanaka, Hitoshi Matsumoto, Yoichi Hayakawa

Article type: Regular Paper
Subject area: [not specified]
2002 Volume 37 Issue 2 Pages 323-328
Published: 2002
Released on J-STAGE: April 25, 2003

DOIhttps://doi.org/10.1303/aez.2002.323

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The parasitoid wasp Cotesia kariyai oviposits into larvae of the armyworm Mythimna (=Pseudaletia) separata. At this time, the coinjection of a polydnavirus and venom is prerequisite for successful parasitoid development. Polydnaviruses are responsible for developmental arrest and interference with the host's immune system; thereby they are called symbiont viruses of the parasitoid wasps. In this study, we demonstrated that C. kariyai polydnaviruses (CkPDVs) replicate in ovarian calyx cells of the host female wasps after pupation. In the course of the replication, DNA synthesis commences by one day after pupation, being followed by capsid protein synthesis. Almost one day after the initiation of the capsid protein synthesis, envelope proteins become visible in the lateral oviducts. Therefore, it is reasonable to assume that the complete virion of CkPDV is not composed simultaneously but requires gradual steps.

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Environmental factors determining wing form in the lygaeid bug, Dimorphopterus japonicus (Heteroptera: Lygaeidae)

Rikiya Sasaki, Fusao Nakasuji, Kenji Fujisaki

Article type: Regular Paper
Subject area: [not specified]
2002 Volume 37 Issue 2 Pages 329-333
Published: 2002
Released on J-STAGE: April 25, 2003

DOIhttps://doi.org/10.1303/aez.2002.329

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Dimorphopterus japonicus, a lygaeid bug which mainly feeds on the eulalia, Miscanthus sinensis, shows a marked wing dimorphism of brachyptery and macroptery. Our preliminary experiments suggested that temperature, photoperiod and density during the nymphal stage are important for the determination of wing form in D. japonicus. The purpose of this study was to elucidate, by more detailed experimentation, the relationships between each environmental factor and the incidence of macroptery. Environmental factors such as high temperature, long photoperiod, and crowding during the nymphal stage stimulated the production of macropters in D. japonicus. Moreover, the incidence of macroptery increased with increase in temperature, photoperiod and density. Results that no macropters appeared at a density of 1, 2 and 5 individuals per container, might indicate that body contact among bugs is necessary for macropter development and the fact that the incidence of macroptery increased, depending on crowding, is suggestive of a strategy for escape from deteriorating habitats. Moreover, both conspecific crowding and seasonal factors, such as temperature and photoperiod, were important in the determination of wing form. The strong effect of seasonal factors such as temperature and photoperiod on wing-form determination implies that wing dimorphism has evolved as a component of seasonal adaptation.

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