Oviposition behavior of the parasitoid, Eumicrosoma blissae (Maki) toward unparasitized eggs of the oriental chinch bug, Cavelerius saccharivorus Okajima was observed in the laboratory. After the female encountered a host egg mass, her oviposition behavior could be divided into nine discrete steps: drumming, extension of ovipositor sheath, probing, drilling, insertion of ovipositor, withdrawal of ovipositor, withdrawal of ovipositor sheath, marking, and retraction of ovipositor sheath. In some cases, insertion of ovipositor did not occur. The parasitoid egg was found only in hosts where a female exhibited ovipositor insertion and marking. When a female attack a parasitized host, she often marked it without ovipositor insertion after drilling. The duration of marking was long when the ovipositor was inserted. The frequency distribution of the number of attacks per host egg was not random. There was a tendency for E. blissae to attempt to insert its ovipositor in the same host egg only once. The characteristics of the oviposition behavior of E. blissae are discussed in comparison with those of other egg parasitoids.

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Control efficacy of Metarhizium anisopliae RNO31 formulation against larvae of the scarab beetle and a population of this fungus were investigated in a sweet potato field. The formulation was made by addition of vegetable oil to bran pellet cultures of the fungus, drying at room temperature to a moisture content of approximately 15% and granulation to about 2 mm in diameter. Insecticidal activity of the formulation was high against the Ist stadium larvae of Anomala cuprea at l0⁵ and l0⁶ colony forming units/g air dried soil. The formulation was applied in ridges or over the entire area of experimental plots at 100 g/m² prior to planting cuttings of sweet potato stems. The percentage of undamaged roots was significantly higher in the plots with application over the entire area than in the control plots on the day of harvest. The percentages of undamaged roots in the fungus application plots were the same as in the fenthion plots. Larvae of Maladera japonica, Holotrichia parallela, Blitopertha orientalis, Anomala rufocuprea and A. cuprea were found in the experimental field. Numbers were very low in the plots with application over the entire area. Populations of M. anisopliae in these plots and in the ridge application plots showed little change from the day of application to the day of harvest.

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Eggs of Plutella xylostella (DBM), 0, 1, 2, 2.5 and 3 days old, were offered to female Trichogramma chilonis in a laboratory experiment. Females oviposited on host eggs of all ages tested. However, the percentage of oviposition was highest on the l-day-old host eggs, and decreased as the host egg became younger or older than the 1-day-old host. Parasitized host eggs did not hatch. The emergence rate was high on the 1-day-old eggs but did not differ among other host ages, except the 3-day-old host. A T. chilonis progeny failed to complete development on the 3-day-old DBM eggs. Hind tibia length of the emerging parasitoid female progeny also tended to decrease as the host egg became older than 2 days. Host age had no significant effect on development time. A method of utilization of the parasitoid in a biological control program against DBM is also discussed based on the effect of DBM egg age on the parasitism of the parasitoid.

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The behavioral responses of Dacne picta, a major insect pest of the shiitake mushroom (Lentinula edodes), to the odor of different stages of this mushroom were investigated by linear track olfactometer in the laboratory. The mushrooms were classified into three stages, growing, mature and decaying according to the life cycle of the mushrooms in the field. The assays were conducted on three growing stages and dried and re-hydrated mushrooms. Both male and female beetles showed chemotactic responses to the odor of all the growing stages and re-hydrated mushrooms. The rates of the beetles attracted to the odor varied among mushrooms belonging to the same stage, but these were not correlated with the amount of mushrooms.

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The prey consumption, development and mortality of Orius sauteri and O. minutus nymphs fed on Frankliniella occidentalis larvae were investigated under 25°C and 16L-8D in the laboratory in order to evaluate the efficiency of the Orius spp. as predators against F. occidentalis. The mortalities of O. sauteri and O. minutus fed on F. occidentalis larvae during the nymphal stages were 51.7% and 72.9%, respectively. These were almost equivalent to those of O. sauteri fed on Thrips palmi larvae and O. insidiosus fed on Sericothrips variabilis adults. Mean sum total nymphal durations of both sexes of both Orius spp. were 14.1 to 14.7 days. These were a little longer than those of O. sauteri fed with T. palmi larvae. Individuals of both sexes of both Orius spp. killed more than 100 F. occidentalis larvae during nymphal development. These results indicate that both O. sauteri and O. minutus may be promising biological control agents for controlling F. occidentalis.

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To clarify the effect of the volatiles of Pinus densiflora on the temporal pattern of departure of Bursaphelenchus xylophilus from Monochamus alternatus adults (nematode departure curve), autoclaved or normal pine twigs were provided to the beetles. Monoterpenoids were not detected from the air of rearing containers with autoclaved pine twigs. A Kolmogorov-Smirnov test showed that there were significant differences in the averaged nematode departure curve between the 2 beetle groups supplied with different foods. The time of 50% nematode departure was shorter in the beetles supplied with autoclaved twigs. The proportion of nematodes which remained in the bodies of 5l-day-old M. alternatus was significantly smaller in the beetles supplied with autoclaved pine twigs. Consequently, it is suggested that B. xylophilus had a trait of spontaneous departure from M. alternatus and that the volatiles from excised normal P. densiflora twigs repressed B. xylophilus departure from M. alternatus.

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Andrographolide, the main constituent of the tropical shrub Andrographis paniculata, was studied for its oviposition deterrence against the diamondback moth (DBM). In the no-choice experiment, andrographolide applied at 1, 000 ppm on five-week-old cabbage plants significantly reduced the number of eggs laid by the moths by about 50%. However, this compound has no oviposition deterrent activity when applied at 250 and 500 ppm. On the other hand, the choice experiment showed that 250, 500 and 1, 000 ppm andrographolide sprays reduced moth oviposition by 72 to 81%.

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The pyrrhocorid bug, Pyrrhocoris sibiricus, which is a ground-dwelling seedfeeder, shows a wing polymorphism producing brachyptery and macroptery. The present study was undertaken to clarify the seasonal variation in the incidence of macroptery in this species. Adults of this species were collected from a field in Okayama from July to December in 1994 and in 1995. Fifth stadium nymphs were also collected from the same field from September to October in 1995. The nymphs were reared at 25°C under 16L-8D. All adults were checked for wing form. It was indicated that the incidence of macroptery showed a seasonal variation in both sexes. In 1994, the incidence of macroptery was high from late August to mid October in females and from mid September to mid October in males. The incidence of macroptery was higher in September than in October in the adults which had emerged from the 5th stadium nymphs. These results indicate that the incidence of macroptery becomes highest in the early autumn. The incidence of macroptery in the autumn was higher in 1994 than in 1995. This may have been attributed to a difference in the length of the hot period.

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The BMC1 element has been found in the Bombyx mori genome as an interspersed repetitious sequence classified as a non-LTR retrotransposon similar to the Ll family in mammals. The BMC1 family has a highly conserved structure ; however, many copies contain defects in their reverse transcriptase domains and 5′-truncations. Duplication of target sequences at the 5′ and 3′ ends of the elements generated by transposition events are readily detected. To attempt gene introduction into the silkworm, B. mori, genome, we used the BMC1 element as a candidate for a transformation vector. A plasmid construct with the element and a cat gene for a reporter was transfected into cultured cells. In the bulk DNA isolated from cells transfected with the plasmid containing or lacking the BMC1 sequence shifted bands were observed only if BMC1 was present. One of five clones isolated from transfected lines has evidence for recombination to B, mori genomic BMC1 sequences. This indicates that this element might be useful for constructing a transformation vector into the B. mori genome.

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Feeding stimulation of soyasaponins on oriental clouded yellow larva, Colias erate poliographus, which feeds on Leguminosae, was investigated. Soyasaponin Bb showed strong feeding stimulation, and Ba and Bc exhibited moderate activity. HPLC analysis of soyasaponins revealed that the content of soyaspaonin Bb was considerably higher than those of Ba and Bc. These results indicated that soyasaponin Bb acts mainly as a feeding stimulant in the host selection of soybean by oriental clouded yellow larvae. The role of soyasaponins in the host selection of oriental clouded yellow larva is discussed.

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Aulacophora nigripennis adults have winter diapause and accumulate myo-inositol during winter. To elucidate the relationship between diapause state and myo-inositol metabolism, two kinds of juvenile hormone analog (JHA), methoprene and pyriproxyfen, were topically applied to the diapausing beetles and subsequent changes in diapause state and myo-inositol content were observed. Application of JHA terminated diapause and also inhibited myo-inositol accumulation. These observations suggest that diapause state and myo-inositol content of this beetle are regulated by the JH endocrine system, although it remains unsolved whether the disappearance of myo-inositol was caused by direct action of JH or by an indirect effect accompanied by diapause termination.

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Effects of ultraviolet (UV) exposure on the survival of Steinernema kushidai infective juveniles (J_III) and its insecticidal activity against the cupreous chafer, Anomala cuprea, Iarvae were examined at 25°C. The UV used was from sunlight and from UV lamps. The peak wavelengths of UV A, UV B and UV C lamps were 350, 310 and 254 nm, respectively. The nematode mortality significantly increased after the exposure to sunlight for 40 min at three intensities (4.3, 3.3 and 3.1 mW/cm²) of UV, and their insecticidal activity decreased. UV A (1.2 mW/cm²) was not harmful to J_III for up to 40 min exposure. Contrarily, all J_III were killed by the exposure to UV B (0.9 mW/cm²) for 5 min and to UV C (0.9 mW/cm²) for 30 s. The insecticidal activity of J_III and the number of A. cuprea cadavers producing nematode progeny after the treatments decreased at 40 min, 5 min and 10 s exposures to sunlight, UV B and UV C, respectively, but did not decrease after the exposure to UV A. Sunlight, UV B and UV C decreased the density of viable symbiotic bacterium. Xenorhabdus japonicus, associated with S. kushidai in the body of J_III.

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A study was conducted to determine the most effective conditions for enhancing the learned response by Ascogaster reticulatus Watanabe, an egg-larval parasitoid of the smaller tea tortrix, Adoxophyes sp. (Lepidoptera : Tortricidae). Female parasitoids were found to learn tea leaf extract with the host egg mass and walk along an extract-treated line. We compared the learned response of females with zero to five oviposition experiences as well as females with various lengths of oviposition time (from contact with host to different lengths of oviposition). Furthermore, we investigated the effect of the length of intervals between experiences on the learned response of females. The learned response of females tended to increase with the number of conditionings (1-3 times) and the oviposition time during conditioning (0-120 s×3). However, responses were low after a single conditioning regardless of oviposition time. The length of the intervals between conditionings (5-120 min) did not affect the learned response of females. It is suggested that learned response through experience is essentially a gradual process in which the number of experiences and the oviposition time during conditioning are major elements.

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An enhancing factor (EF) from Pseudaletia separata entomopoxvirus was serologically related to the fusolin but unrelated to the spheroidin. The spheroid contained a protein serologically related to the EF and the fusolin. The EF consisted of a protein and a polysaccharide.

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The distribution of the great mormon butterfly, Papilio memnon L., has been expanding to northeastern areas in the Kinki district in western Japan. To investigate the relationship between the phenomenon and characteristics of diapause of this species, the photoperiodic response of 4 Japanese populations including the subtropical and northernmost ones was examined. The critical photoperiod for inducing diapause at 20°C was 12 h 30 min in a subtropical population in Naze City (28°23′N), and about 13 h in temperate populations in Kagoshima (31°36′N), Wakayama (34°11′N), and Mino (34°54′N) Cities. Latitudinal variation was not found in diapause intensity (94-111 days) among the 3 temperate populations. However, diapause incidence at 13.5L-l0.5D, which is slightly longer than the critical photoperiod, increased with latitude of the locality, and the deepest diapause was observed in some individuals in the Mino population. Nevertheless, the differences in critical photoperiod and diapause intensity among populations was smaller than that among broods in each population. As it appears to be difficult to explain the recent northward invasion of this species only by this slight change in diapause trait, the influence of climatic warming on the phenomenon is also discussed.

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The Intergovernmental Panel on Climate Change (IPCC) estimated that the global mean surface air temperature will increase about 2°C above the 1990 level by 2100. Such an increase in temperature may result in an increase in the number of generations per year of most insects. Several simulation models have been constructed to predict the increase in the number of generations, but these require a great deal of calculation to obtain estimates for many insect species at various locations under various scenarios of global warming. This paper proposes an analytical method to enable a quick estimation. Two assumptions are used : (1) The developmental rate of insects is approximately given by a linear function of temperature (T), with a developmental zero (T₀) and a thermal constant (K). (2) The increase in temperature is approximately even throughout the year. Let m be the current annual mean temperature at a given location, and ΔT the potential increase in temperature under global warming at the location. If the temperature before the ΔT-rise is higher than T₀ in summer and lower than (T₀-ΔT) in winter, the increase in the number of generations per year, which is denoted by ΔN, is approximately given by ΔN≈ΔT[c+ d(m-T₀)]/K, where c and d are constants. The validity of the approximation is checked using the "smoothed daily normals" in Japan obtained as a running mean of 15 successive daily normals where a daily normal is defined as the averaged daily temperatures for 30 years from 1960 to 1990. The estimates are c=204.4 and d=12.46. Using this formula, linear isoclines of ΔN are plotted in a graph of T₀ versus K. By plotting the T₀ and K of various insects in this graph, we can estimate the increase in the number of generations under global warming in temperate zones.

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A total of 19 parasitoid species belonging to the families Eulophidae (17 species), Pteromalidae (1), and Braconidae (1) were reared from larvae of the peach leafminer Lyonetia clerkella (Linnaeus) in Tsukuba in 1993-1995. Chrysocharis nitetis (Walker) was the most frequent parasitoid. Species composition of parasitoids associated with L. clerkella in Kagoshima Prefecture was also investigated in 1995. All 13 species reared were common to those in Tsukuba, but the relative abundance of each species was markedly different.

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We purified Antheraea pernyi arylphorin (ApA) from the larval hemolymph by gel permeation chromatography, DE-52 cellulose column chromatography, and hydroxyapatite column chromatography. Our results show that ApA is a hexameric protein with a native molecular weight of 450, 000, and consists of three molecules of two subunits each weighing 83, 000 and 82, 000. ApA is rich in tyrosine (8.2%) and phenylalanine (8.4%) and poor in methionine (1.4%). The amounts of ApA in the hemolymph increased during the feeding stage and decreased during the molting stage. ApA was partially recaptured by the fat bodies during the larval-pupal metamorphosis. ApA remained in the hemolymph and also in the fat bodies at a constant level throughout the diapause pupal stage but was then reduced to traces just before adult emergence. In vitro translation of RNA from the fat bodies and immunoprecipitation using anti-ApA serum showed that ApA synthesis occurs in the fat bodies through the feeding stage but is reduced remarkably after spinning. The translatable ApAmRNA was not detected at pupation at all.

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Acetylcholinesterase (AChE) inhibiting activity of eight 3-alkylsulfonylphenyl methanesulfonates was measured and its relationship with the structure of substituted alkyl moieties was analyzed in susceptible and resistant strains of Culex tritaeniorhynchus. The activity of the compounds was not so potent as that for the green rice leafhopper, Nephotettix cincticeps, previously reported. However, a parabolic relationship of the activity was detected with the distance between the S atom and the distal C atom of the alkyl moiety. The shape of the parabolic curve and the optimum distance were the same in susceptible and resistant strains, but the activity was about 100 times higher for AChE of the susceptible strain than for that of the resistant strain. No significant relationship was detected with the steric constant. An activity structure relationship was, however, detected with the steric constant in N. cincticeps, but not with the distance S-C, based on the previous results. Considering that the sulfone moiety of methanesulfonates conjugates with the esteratic subsite of the AChE active site to inhibit its activity, a structural change apparently occurred in the esteratic subsite of AChE in the resistant strain of C. tritaeniorhynchus, and was different from that of N. cincticeps.

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In order to analyze the complex endosymbiotic system of aphids, immunohistochemical double staining was conducted using anti-GroEL and anti-GroES polyclonal antibodies. By this method, primary and secondary intracellular symbiotic bacteria were vividly differentiated by color on the same tissue sections of disymbiotic species from diverse aphid taxa. The primary symbionts were detected with anti-GroEL antiserum in pink while the secondary symbionts were stained with anti-GroES antiserum in dark brown. On account of its wide applicability, and high selectivity and resolution, this method will be a useful tool in investigating the nature, origin and dynamic evolution of the endosymbiotic system in aphids.

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The Mexican bean beetle, Epilachna varivestis, was confirmed in leguminous vegetable fields in Yamanashi and Nagano Prefectures, central Honshu, Japan in the summer of 1997. It was estimated that this species had already colonized these areas about four or five years earlier, and that the adults can survive the winter there.

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A juvenile hormone analog, fenoxycarb, was topically applied to 5th stadium larvae of the silkworm, Bombyx mori, and the subsequent growth of the larvae was investigated. When fenoxycarb was applied on days 0 to 5 of the 5th stadium, the length of the stage increased and the rate of pupation decreased in a dose-dependent manner. During this period, the later the larvae were treated, the greater were the effects. The treatments also delayed the growth of the silk glands and the rise of the hemolymph ecdysteroid titer in a dose-dependent manner. In addition to the prolongation of the 5th stadium, treatment on days 3 to 5 induced a supernumerary molt to the 6th stadium with pupal characteristics. In these animals, the ecdysteroid titer increased from the day after the treatment and peaked at time of head capsule slippage. Treatment on day 6 or 7 had only slight effects on the subsequent growth. These results indicate that the feeding period of the 5th stadium can be divided into three stages according to the animal's responses to fenoxycarb.

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