The bumble bee Bombus terrestris L. is an effective pollinator in the cultivation of greenhouse hot pepper Capsicum annuum L. Data indicates that colony traffic and foraging activity was highest at 25.7°C in greenhouse, whereas at 32.7°C, the foraging activity and colony traffic decreased 69.7 and 40.0%, respectively. By increasing the number of larvae and workers, the colony traffic and foraging activity also increased, respectively. Moderate temperature in the morning probably facilitates the overall activity of bees in a greenhouse. The data indicates that bumble bee pollination increased the fruit mass and number of seeds by 27.2 and 47.8%, respectively, compared to that of the control. These significant results substantiate the effectiveness of bumble bees in the pollination of pepper grown in greenhouses.

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The aims of this paper have been (a) to document postembryonic eye growth in the common laboratory stick insect Carausius morosus and (b) to examine whether the capacity of the eye to adapt to changing light intensities varied with age. We found that number of facets, corneal thickness, ommatidial diameter, widths of cone and retinal layers, and rhabdom volume increased linearly. Interommatidial angles, pigment grain sizes, and microvillar diameters, however, remained approximately the same. On the basis of the morphometric data we calculated that sensitivity in the adult stick insect eye was at least tenfold that of the eye of first instar nymphs and could show that adults would be able to perceive a similar amount of detail at considerably dimmer ambient light than the smaller individuals. In terms of resolving power this means that light- and dark-adapted first instar stick insects possess acceptance angles of 5.3° and 8°, respectively and that the corresponding figures for the adult eye are 4.7° and 7.3°. The bigger (and more light-sensitive) eye of fully grown C. morosus makes protection against radiation damage a more serious issue in the adult individual than the small first instar. The findings explain why smaller (=younger) stick insects are less nocturnal than mature, fully-grown individuals. It is, thus, not surprising to see that dark/light adaptational photomechanical changes affecting pigment position and rhabdom widths, are more pronounced in the eyes of the adults.

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Herbivorous arthropod fauna of the horse nettle Solanum carolinense L., an alien solanaceous herb of North American origin, was characterized by surveying arthropod communities in the fields and comparing them with the original community compiled from published data to infer the impact of herbivores on the weed in the introduced region. Field surveys were carried out in the central part of mainland Japan for five years including an intensive regular survey in 1992. Thirty-nine arthropod species were found feeding on the weed. The leaf, stem, flower and fruit of the weed were infested by the herbivores. The comparison of characteristics of the arthropod community with those of the community in the USA indicated that more sapsuckers and less chewers were on the weed in Japan than in the USA. The community in Japan was composed of high proportions of polyphages and exophages compared to that in the USA. Eighty-seven percent of the species are known to be pests of agricultural crops. Low species diversity of the community was also suggested. The depauperated herbivore community, in terms of feeding habit and niche on S. carolinense, suggested that the weed partly escaped from herbivory in its reproductive parts. The regular population census, however, indicated that a dominant coccinellid beetle, Epilachna vigintioctopunctata, caused a noticeable damage on the leaves of the weed.

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Sperm storage in Adalia bipunctata (L.) (Coleoptera, Coccinellidae) was examined and compared between diapausing and non-diapausing females. We observed that non-diapausing females store on average 13,688 (±722, S.E.) sperm in their spermatheca and that every female examined had sperm in storage (n=16). In contrast, most diapausing females had empty spermatheca and only two had sperm in storage (n=15). Mean sperm number in diapausing females was 250 (±112, S.E.). The mean length of the spermatozoa stored by non-diapausing females was 2,068.5 μm (±9.8, S.E.), ranging from 1,530.8 to 3,171.7 μm. Sperm length in diapausing females was only measurable in one female and was of 2,102.9 μm (±22.4, S.E.).

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The nutrient intake of the third instar larvae of Anomala cuprea (Ac) and Protaetia orientalis submarmorea (Pos) (Coleoptera: Scarabaeidae) from a mixture of cow dung and wood chips of two wood species (Cryptomeria japonica and Quercus mongolica), was assayed by the stable isotope technique. The values of δ¹⁵N and δ¹³C (deviations of ¹⁵N/¹⁴N and ¹³C/¹²C from the standard materials) were measured in the following samples: (1) the integument plus the head of the 3rd instar larvae of both species reared in 1999 autumn fed with a mixture of cow dung and wood chips or with leaf mold, (2) cow dung, (3) wood chips, and (4) leaf mold as the larval food before onset of rearing. The δ values of the bodies of larvae fed with leaf mold differed with the beetle species. The δ¹⁵N values of the larval bodies of both species fed with the mixture were close to those of cow dung, whereas the δ¹³C values were in between those of cow dung and wood chips. Therefore, both species were presumed to obtain almost all their nitrogen from cow dung, and their carbon from both cow dung and wood chips.

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In species of several insect orders and spiders, it has been shown that the size of male genitalia relative to body size decreases as the body becomes larger (negative allometry), while the relative size of other morphological traits tends to be constant. Such a contrast between genital and somatic traits suggests stabilizing sexual selection on male genitalia: males with small or large genitalia are prone to fail to inseminate females due to incompatibility of their genitalia. In the present study, we tested the contrast between genital and somatic traits for males of a lepidopteran insect, Ostrinia latipennis. We examined allometry of five genital and 11 somatic traits for each of three local populations of O. latipennis. Of the 15 allometric slopes for genital traits, 14 showed significantly negative allometry, whereas none of the 33 slopes for somatic traits represented negative allometry. These results showed that the size of male genitalia in O. latipennis is more stable than the size of somatic traits against changes in body size. This study supports Eberhard et al.'s (1998) hypothesis which states that the low genital allometry in insects and spiders is caused by sexual selection. Based on currently available information on genital morphology and sexual communication in O. latipennis, it seems unlikely that the lock-and-key hypothesis is responsible for the stable genital size in this species.

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Eobiana engelhardti subtropica (formerly Metrioptera hime) is wing-dimorphic. The long-winged (LW) morph was clearly induced by crowding during the nymphal stages. Short-winged (SW) females produced eggs more intensively in an earlier period than did LW females. This difference in egg production between the two wing morphs seems to be associated with different patterns of increase in body weight after adult emergence. The body weight of SW females rapidly increased and reached its peak at about the time when oviposition started. On the other hand, the increase in body weight of LW females was slow, although it continued even after the start of oviposition. These findings suggest that the SW morph is adapted to sedentary life and rapid reproduction and that the LW morph tends to migrate before or during reproduction. However, in both the morphs, reproductive traits (pre-oviposition period, egg-laying period, number of eggs laid, and longevity) were to some extent flexible and could be modified by photoperiodic conditions.

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We examined the effect of moth age and photoregime on the timing of male response to sex pheromones in male Cnaphalocrocis medinalis. The responsiveness of males varied with age, increasing up to 3-days and then remaining constant to 7-days. In male responses to the pheromone throughout the scotophase under five different photoregimes, it was shown that the time to reach the maximal response level after lights-off was rather constant (ca. 4 h), regardless of the duration of the scotophase in a range from 6 to 18 h. The maximal response level in every case appeared to be maintained until the end of the scotophase. Furthermore, in the experiment involving ±3 h shifts of lights-off or lights-on timing from the usual 15L:9D, the male responsiveness increased within 4 h after lights-off, and the maximal level extended throughout the remaining dark period. These results suggest that, at least under the present experimental conditions, only lights-off and lights-on cues are critical for the timing of the increase and decrease in responsiveness. No responsiveness was observed under light conditions, showing that light inhibits the responsiveness of males to sex pheromones.

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When examined with a phase-contrast microscope, all of the 15 Bacillus thuringiensis serovar yunnanensis (H20ab) strains, the reference type strain and the 14 Japanese isolates, produced large rhomboidal inclusions in spore-lacking cells but not in spore-forming cells. No envelopes were associated with inclusions. Inclusion matrix consisted of electron-dense homogeneous substances. The frequency of inclusion-forming cells was <1% of the cell population in each strain. Also, phase-dark spherical bodies, much smaller than rhomboidal inclusions, were often associated with cells in sporulating cultures. Electron microscopic studies with the four selected yunnanensis strains revealed that: (1) the majority of cells produced spores but not crystalline inclusions, (2) formation of crystalline inclusions was limited to the spore-lacking cells, and (3) electron-dense round bodies, much smaller than rhomboidal crystalline inclusions and putatively assigned to poly-β-hydroxybutyrate inclusions, were often observed in both spore-forming cells and inclusion-forming asporogenous cells. The overall results strongly suggest that the formation of crystalline inclusions in asporogenous cells is an H serotype-specific phenotype characteristic of the B. thuringiensis serovar yunnanensis.

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The sugi bark borer, Semanotus japonicus, occurs naturally in Honshu, Shikoku, Sado Is., Oki Is., and Yaku Is. in Japan, and its main host tree is the Japanese cedar, Cryptomeria japonica. Because the geographical structure of the morphological characters largely corresponds to the sites of the glacial refugia and the post-Pleistocene dispersal route of the Japanese cedar, the history of the cedar was postulated to have shaped the genetic population structure in the borer. In this study, we used partial sequences from mitochondrial DNA genes, the COI, tRNA^Leu-UUR and COII to elucidate processes in the geographical structuring of S. japonicus populations. Ten haplotypes were revealed among 52 individuals from four populations that ranged from Iwate to Ehime prefectures. The geographical distribution of these haplotypes was highly structured. Two distinct lineages were detected, which probably represented the Pacific coastal and the Japan Sea side lineages, from the neighbour-joining method and haplotype networking. As haplotypes of both Pacific and Japan Sea lineages were found in the Iwate population, a second contact might have occurred in the Tohoku area. These results suggested that the present genetic structure of S. japonicus was determined by the host's past history.

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The brown citrus aphid, Toxoptera citricidus, was attacked by the parasitoid Lysiphlebus japonicus, and was actively attended by two ant species, Lasius niger and Pristomyrmex pungens. The impacts of the two ants on the parasitism of the aphid by the parasitoid were assessed experimentally at a no-pesticide mandarin grove. Aphid colonies were artificially initiated on young citrus shoots in summer. Lysiphlebus japonicus females were frequently observed foraging in aphid colonies attended by P. pungens, but rarely in colonies attended by L. niger and colonies where ants were excluded. L. japonicus females were attacked by P. pungens workers, but oviposited successfully by avoiding the ants. Large predators were excluded by both ant species from the aphid colonies, while they were abundant in ant-excluded colonies. L. niger workers often carried living aphids away from the attended colonies, whereas P. pungens removed no aphids and disregarded parasitized aphids, thereby incidentally protecting the parasitized aphids from predators. Consequently, L. japonicus-mummies were formed in great numbers in colonies attended by P. pungens, but were scarce in colonies attended by L. niger and ant-excluded colonies. Aphid-attending P. pungens workers reduced predation and hyperparasitism on L. japonicus larvae within mummies. Thus, P. pungens attending T. citricidus largely enhances parasitism by L. japonicus and its larval survival, compared with when ants are absent, whereas L. niger exerts no remarkable impact.

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Myo-inositol was found in the hemolymph of three species of rice planthoppers, Nilaparvata lugens, Laodelphax striatellus and Sogatella furcifera, along with the major common components by ¹H-NMR spectroscopy. Myo-inositol concentration was about three to five times higher than trehalose concentration. N. lugens nymphs as well as adults contained myo-inositol. Trace experiments with ¹³C-NMR spectroscopy showed that myo-inositol was produced from glucose and accumulated in the hemolymph with a peak concentration appearing later than that of trehalose. The role of myo-inositol in rice planthoppers is discussed.

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We tested the response of the herbivorous mite Tetranychus urticae to uninfested lima bean leaves exposed to herbivore-induced conspecific plant volatiles by using a Y-tube olfactometer. First, we confirmed that exposed uninfested leaves next to infested leaves were more attractive to carnivorous mites Phytoseiulus persimilis than uninfested leaves next to uninfested conspecific leaves. Under the same conditions, uninfested leaves next to infested conspecific leaves were more attractive to T. urticae than uninfested leaves next to uninfested leaves. Based on these data, we discuss the role of the volatiles from the exposed plants in a tritrophic system.

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The sugi bark borer, Semanotus japonicus, occurs naturally in Honshu, Shikoku, Sado Is., Oki Is., and Yaku Is. in Japan, and its main host tree is the Japanese cedar, Cryptomeria japonica. Because of a correspondence between the present distribution of geographical variation in the borer and the refugia of the Japanese cedar during the last full-glacial period, isolation of the cedar is thought to have caused differentiation in the borer between local populations. In this study, we used morphological information to elucidate the geographical differentiation of S. japonicus populations. Multivariate analyses were performed based on ten morphological characters for ten populations. Populations between the Pacific coast side and the Wakasa Bay area showed remarkable variation in morphological characters. Because the distribution of the refugia of the cedar coincided with the patterns of morphological variations in S. japonicus, it is suggested that the geographical structure of the present S. japonicus population was caused by isolation during the last glacial period. While vicariance is no longer a factor with the expansion of C. japonica's distribution, its past effects may have been important enough to influence the present genetic structure of S. japonicus.

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Alarm pheromone activity was demonstrated in a hexane rinse of the mite Histiogaster rotundus Woodring (Acari: Acaridae). Silica gel column chromatography of the hexane rinse from 1,000 mites afforded an active fraction consisting solely of neryl formate [3,7-dimethyl-(Z)-2,6-octadienyl formate] by GC/MS analysis. Synthetic neryl formate triggered the same escape behavior at 1–100 ng. On average 6.7±0.5 ng of the pheromone was contained in a female, and 10.1±0.5 ng in a male.

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Apple (Malus domestica Borkh.) trees that had not been sprayed with either insecticides or miticides were explored for the occurrence of tetranychid and phytoseiid mites, and predatory characteristics of the phytoseiid mites were investigated in the laboratory at 20±0.5°C, with a 15L : 9D photoperiod and 90±5% RH, to find an appropriate domestic phytoseiid predator for controlling Panonychus ulmi (Koch) in Japan. Amblyseius womersleyi Schicha, Amblyeseius tsugawai Ehara and Typhlodromus vulgaris Ehara were found on apple trees inhabiting P. ulmi and Tetranychus urticae Koch. Among phytoseiid mites sampled, T. vulgaris showed a favorable developmental ratio of 75% with the female ratio of 67%, when reared on P. ulmi. Mated females of T. vulgaris laid eggs when fed larvae and adults of P. ulmi. On the contrary, immature stages of T. vulgaris neither consumed prey nor developed, and mated females reared on P. ulmi laid no eggs when fed T. urticae. Therefore, T. vulgaris was expected to be an effective predator for suppressing the P. ulmi population in apple orchards under reduced spray programs.

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In order to assess the efficacy of Crotalaria juncea and C. spectabilis as trap crops against the soybean cyst nematode, Heterodera glycines, rates of hatching of H. glycines eggs in the root leachate, penetration into Crotalaria roots by H. glycines juveniles and their development in the roots, and the effects of planting these Crotalaria species on population density of H. glycines in soil were investigated. The rates of hatching of H. glycines eggs in the root leachates from C. juncea and C. spectabilis were significantly greater than the rates in distilled water and in the leachates from non-host plants. Stimulation of hatching by C. juncea was significantly greater than that by C. spectabilis and similar to that by the host plant, kidney bean. The number of second-stage juveniles that penetrated Crotalaria roots was similar to the number that penetrated soybean roots, but most of the second-stage juveniles in Crotalaria roots did not develop to an advanced stage of growth. The population density of H. glycines in soil in which Crotalaria had been planted decreased significantly compared with that in fallow soil (no plants) in both pot and field plot tests. The effect of planting C. juncea on reduction in population of the nematode in soil was generally greater than that of C. spectabilis. From the results of these experiments, it was concluded that the use of Crotalaria, especially C. juncea, as a trap crop is a promising method for reducing the population density of H. glycines.

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Six compounds were identified from the millipede Oxidus gracilis (C. L. Koch). They were benzaldehyde, mandelonitrile, phenol, p-cresol, benzaldehyde dimethyl acetal, and creosol (2-methoxy-4-methyl phenol). Except for benzaldehyde, all were detected for the first time from this millipede. Mandelonitrile was the major component of the six compounds. The others were trace constituents and significantly varied in quantity depending on the site of collection, suggesting an influence of environmental factors on their production.

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The Vat gene of melon confers resistance to Aphis gossypii through both antixenotic and antibiotic mechanisms. This article reports several experiments carried out to detect this gene in melon lines from a melon breeding program. These included antixenosis, antibiosis and virus transmission trials. Results showed that, for Vat detection, antibiosis trials were not as discriminating as antixenosis trials. The antixenosis trials discriminated more clearly between resistant and susceptible lines after 72 h than after 24 h. We additionally developed a rapid and simple choice-test method to assess antixenotic effect. This test discriminated rapidly and effectively between resistant and susceptible lines. The aphids showed significant rejection of resistant lines after only 1.5 h of exposure. Thus compared to the conventional antixenosis trials this test has several advantages, including rapidity, ease of use, and non-destructiveness (allowing replicate testing of a single plant, or subsequent obtention of seed).

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Studies were conducted in three flat storerooms in Southern Greece, filled with approx. 45 tons of wheat each, stored in 1.5 m deep bulks, in order to examine the seasonal abundance of insect and mite species, in relation to their horizontal and vertical spatial distribution into the bulked grain. For this purpose, wheat samples were taken from June 2000 until March 2001, at 10-day intervals, by using a partitioned grain trier. The surface of the grain bulk was divided into three sampling zones, the central zone (the central part of the bulk), the edge zone (close to the walls) and the corners (the corners of the store rooms). The trier samples were examined separately for the upper, medial and lower 0.5 m of the bulk. Significant differences were recorded for wheat moisture content among zones (p<0.0001) and among depths (p=0.0012). On the contrary, no significant differences were noted for temperature among zones (p=0.2281) and depths (p=0.3049). In general, the moisture content was higher in the upper 0.5 m of the bulk, compared to the other two depths. Temperature decreased during the sampling period and this reduction was more vigorous from October and on. Eight insect species and 25 mite taxa were found during the sampling period. The most abundant insect species were Plodia interpunctella Hübner (Lepidoptera: Pyralidae), Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) and Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae). The most abundant mite species were Acaropsis sollers Rohdendorf (Prostigmata: Cheyletidae), Tyrophagus putrescentiae (Schrank) (Astigmata: Acaridae) and Glycyphagus domesticus (De Geer) (Astigmata: Glycyphagidae). For the majority of the most abundant insect and mite species, the highest population densities were recorded during autumn. More individuals were found at the corners and the central zone, compared to the edge zone. In addition, significantly more individuals were found in the upper 0.5 m of the bulk (p<0.05), compared to the other two depths, with the exception of A. sollers which was equally distributed in the upper 1 m. All the aforementioned species of insects and mites showed an aggregated spatial pattern, as indicated by Taylor's Power Law estimates. The use of Taylor's parameters for the estimation of accuracies and sample sizes for the most abundant species indicated that these parameters were notably varied among species.

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Laboratory experiments were carried out to clarify the bodyguard effects for the aphid, Aphis craccivora Koch, against predatory ladybeetle larva, Coccinella septempunctata L., by two ant species, Tetramorium caespitum Linnaeus and Lasius niger L. In particular, we examined the effectiveness of protection for aphids as related to ant activities on a plant. The number of attacks on a ladybeetle larva by ants until the ladybeetle larva dropped from the plant did not differ between the two ant species, suggesting similar aggressiveness of the two ant species. However, the number of attacks per min by L. niger was five times greater than that by T. caespitum. Consequently, the residence time of the ladybeetle larva was shorter and the proportion of aphids eaten was lower in the presence of L. niger than in the presence of T. caespitum. Thus, the encounter rate between ants and predators is one of the most important factors for bodyguard effects on aphids, resulting from the markedly different foraging behaviors of the two ant species.

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