Intraspecific competition of larvae in superparasitism was examined in Meteorus pulchricornis (Hymenoptera: Braconidae), a solitary endoparasitoid of lepidopteran larvae. The outcome of competition principally depended on the time interval between two ovipositions by conspecific females. Lethal symmetrical competition by physical attacks with sharp mandibles occurred between first-instar larvae just after or before hatching when two eggs were laid almost simultaneously into the same host within 30 min. During asymmetrical competition between first-instar larvae oviposited at an interval of 24 h, older larvae tended to win against younger ones. However, during competition between first- and second-instar larvae oviposited at an interval of 72 h, the first instar always killed amandibulate second instars by physical attacks using the mandibles. In contrast, obvious developmental delays, but not death, of young first-instar larvae were detected as a result of asymmetrical competition at a 96-h interval. We did not observe egg mortality during either symmetrical or asymmetrical competition.

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Polyoxin AL water-soluble powder (Polyoxin AL), a fungicide that inhibits chitin synthase, showed a synergistic effect with benzoylphenyl urea insect growth regulators (BPU-IGRs) in killing Spodoptera litura larvae. First, eight different commercially available insecticides were examined for a synergistic effect with Polyoxin AL in killing S. litura. Only Cascade, one of the BPU-IGRs, showed a synergistic effect. Next, eight BPU chemicals (six BPU-IGRs including Cascade and two reagents) were used. All eight chemicals showed a synergistic effect except for Dimilin. Finally, six fungicides, including Polyoxin AL, were examined for a synergistic effect with Cascade. Only Polyoxin AL showed a synergistic effect. These results suggest that the synergistic effect was specific for the combination of BPU chemicals and Polyoxin AL.

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The insecticidal effect of a water-soluble powder of Polyoxin AL, a fungicide that inhibits chitin synthase, on the larvae of Bombyx mori, Mamestra brassicae, Mythimna separata, and Spodoptera litura was examined. After the fungicide was mixed in diet and applied orally, all the larvae of S. litura, M. separata, and M. brassicae died at the molting stage at polyoxin levels of 0.03, 0.1, and 0.3% (wt/wt), respectively. A morphological study with S. litura showed that the larvae to which Polyoxin AL was orally applied failed to form a new cuticle. The median lethal concentration (LC₅₀) of Polyoxin AL in S. litura 3rd stadium larvae was approximately 0.02%. Polyoxin AL had little effect on B. mori, even at 0.3% in the diet. The standard chemicals polyoxin B, polyoxin D, and nikkomycin Z were applied orally to S. litura 3rd stadium larvae. All the larvae were killed after exposure to 0.005% polyoxin B and 0.015% nikkomycin Z. Polyoxin D, however, had no effect even at 0.015%. Polyoxin B and D were injected into the hemocoel of S. litura and B. mori with a syringe. The responses of these insects were quite different. In S. litura, both the chemicals inhibited metamorphosis. In B. mori, polyoxin B inhibited the larval molt, whereas polyoxin D had no effect. Body surface treatment with 1% (wt/vol) Polyoxin AL resulted in a failure to molt in both species.

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The ladybird beetle, Harmonia axyridis (Pallas), was studied under laboratory condition to reveal the effect of food stress on phenotypic changes in life history traits that reflect larval and adult performance. Two food environments (abundant and limited food availability) were used as experimental treatments. When the food was limited, larvae grew slowly. Surviving adults were smaller, and their pre-reproductive period was considerably prolonged, reproductive life span and fecundity were reduced, and longevity was increased. On limited food supply, adults had reduced efficiency of converting food into eggs in comparison to adults provided abundant food supply. The relationships between lifetime fecundity and female longevity suggested that for both food levels, there were two groups of individuals with one group showing a positive correlation and the other group a negative correlation between reproduction and longevity. Life history responses to food stress, and the trade-off between fecundity and female longevity, are discussed.

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The bacterium Pantoea agglomerans pv. millettiae (=Erwinia herbicola pv. millettiae) induces galls on the trunks and twigs of Wisteria floribunda (Fabaceae) in central Japan. We sampled bacterium galls from wisteria at six sites and report a diverse arthropod community, composed of 48 species, representing 33 families and 11 orders, associated with the galls. Dominant arthropods were the larvae of Matsumuraeses falcana (Lepidoptera: Tortricidae) and Synanthedon tenuis (Lepidoptera: Sesiidae) as facultative cecidophages, and Eudigraphis takakuwai takakuwai (Diplopoda: Polyxenidae) as a scavenger. The number of species, abundance of each feeding guild, and overall arthropod abundance were positively correlated with gall diameter.

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The soybean aphid, Aphis glycines Matsumura, is a pest of soybean [Glycine max L. (Merrill)] in Asia, and its recent establishment in North America has led to large, recurring outbreaks that have challenged pest management practitioners to seek environmentally responsible means for its control. Growth-chamber experiments identified resistance to A. glycines in soybean lines ‘Perrin’; ‘Tracy-M,’ its glabrous near-isoline ‘D88-5328,’ and its densely pubescent near-isoline ‘D88-5272’; ‘D75-10169,’ its glabrous near-isoline ‘D90-9216,’ and a densely pubescent near-isoline ‘D90-9220.’ Tracy-M and D75-10169 were antixenotic to A. glycines in host-selection tests. In no-choice nymphiposition tests, the number of nymphs deposited by A. glycines on D75-10169, Perrin, and Tracy-M did not differ from that on other lines after 24- and 48-h test periods. Under conditions in which A. glycines were free to distribute on plants over a 48-h period, aphids were found primarily on stems and trifoliolate leaves of Perrin, Tracy-M, D75-10169 and a resistant control, ‘Dowling,’ whereas the majority of aphids infesting susceptible lines ‘91B91’ and ‘Davis’ were distributed on unifoliolate leaves. Irrespective of shoot structure, low numbers of A. glycines were found on Dowling compared to other lines. The mean number of days to reproductive maturity for A. glycines did not differ among lines. Aphis glycines produced fewer nymphs during the first 7 d of reproduction on Perrin, Tracy-M, D75-10169 and Dowling compared to Davis, and fewer A. glycines progeny were produced on D75-10169 and Dowling than on 91B91. Results show that Dowling continues to be a strong source of resistance to A. glycines. Perrin, Tracy-M, and D75-10169 have been used as sources of resistance to other insects, and discovery of resistance to A. glycines in these three lines may increase their utility in soybean breeding programs.

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Introduced soil animals have frequently affected native fauna on oceanic islands that have never been connected to a continental land mass. Alien soil animals can be unintentionally introduced via transfer in potted plants or by commercial trade among islands and continental landmasses. Hot water treatment to destroy pests has recently been used during the quarantine of ornamental plants. To examine the possibility of using hot water treatment for introduced soil animals in potted plants, an experiment was performed to determine whether hot water treatment (immersion in water at 40, 43, 45, 47, and 50°C for 5 min) kills soil animals. I examined four taxa (different phyla) of soil invertebrates that have been introduced to the oceanic Ogasawara (Bonin) Islands, approximately 1,000 km south of the Japanese mainland. The species used were: the invasive alien terrestrial flatworm Platydemus manokwari (Platyhelminthes); an unidentified alien species of earthworm (Annelida); the alien snail Acusta despecta sieboldiana (Mollusca); and the alien ant Technomyrmex albipes (Arthropoda). The water temperature required to kill flatworms (≥43°C) and earthworms (≥43°C) was lower than that to kill snails (≥50°C) and ants (≥47°C). Use of hot water for protection from alien soil animal invasions may mitigate their environmental impacts, particularly on oceanic islands where valuable biota could be threatened.

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It has been known that diapause is not induced in populations of the two-spotted spider mite, Tetranychus urticae, under continuous darkness (DD). When the light intensity was changed under LD 8:16 at 18°C, the threshold intensity for blue light (475 nm) to induce 50% of diapause was below 50 mW/m²; and the blue light was most effective in photoperiodic induction of diapause. The threshold intensities for green (572 nm) and orange (612 nm) light were 50–500 and 500–2,500 mW/m², respectively. T. urticae showed no sensitivity to red light (658 nm) even at 2,500 mW/m² intensity. Low diapause incidence under long wavelengths was probably due to the absence of photoreception by photoreceptor pigments for photoperiodic time measurement, or for circadian entrainment required for photoperiodic induction.

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The sorghum plant bug Stenotus rubrovittatus (Matsumura) (Heteroptera: Miridae) is a major seed pest of rice in Japan. Male S. rubrovittatus were previously shown to be attracted to traps baited with unmated females. The solvent extract of unmated females was analyzed by GC-MS using HP-INNOWax and HP-5ms columns, and retention index data and mass spectra of peaks detected in the female extract were compared with those of authentic samples. Three compounds, hexyl butyrate (=butanoate), (E)-hex-2-en-1-yl butyrate and (E)-4-oxohex-2-enal, were identified from the female extract. Contents of these compounds in solvent extract of females were ca. 18.6, 8.6 and 1.0 μg/female, respectively. In a field experiment, a blend of three compounds showed potent attractant activity to male S. rubrovittatus, although no binary combinations of the three components were attractive. These results suggested that these compounds are components of the female sex attractant pheromone of S. rubrovittatus.

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The current study was conducted to investigate the pathogenicity and its mode of action by Verticillium lecanii hybrid strains in different sedentary stages of Heterodera glycines. Three different sedentary stages (pale yellow female, yellow brown cyst, and dark brown cyst) of H. glycines were treated with V. lecanii and incubated for 3 weeks on water agar. After 3 weeks of incubation, eggs were investigated for the following parameters: (i) the infection frequencies of eggs, (ii) the number of eggs laid, and (iii) the number of mature and healthy eggs. Subsequently, the fecundity of H. glycines treated with V. lecanii was investigated in greater detail. Consequently, some strains had a greater ability to infect eggs and this significantly reduced the number of eggs laid and mature eggs in pale yellow females. This study indicates that V. lecanii is more effective on females rather than cysts of H. glycines and that V. lecanii may act on H. glycines in multiple ways.

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To determine the effect of xylem hardness and larval body size on the pupal-chamber tunnels (hereafter PCTs) made by Monochamus alternatus, newly hatched larvae were inoculated on Abies sachalinensis, Picea jezoensis, and Pinus densiflora logs and reared in the laboratory. After most larvae had developed well, larval body size and PCT size were measured. Larval body mass was significantly heavier in P. jezoensis and P. densiflora than in A. sachalinensis. ANCOVA with larval body mass as a covariate indicated that the adjusted mean of the median depth of the PCTs was greater in A. sachalinensis and P. jezoensis than in P. densiflora and that the adjusted mean of the PCT length was greater in P. jezoensis than in the two other tree species. P. densiflora xylem is known to be harder than the two other conifers. Consequently, it can be concluded that larvae of equal body mass make deeper and longer PCTs in soft xylem than in hard xylem.

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The heat shock protein gene, hsp70, was cloned and sequenced from the diamondback moth, Plutella xylostella (L.). cDNA sequence analysis revealed a 1,992 bp-long open reading frame, which encodes a protein with a calculated molecular weight of 72.2 kDa. Results of Southern blot analysis suggested the presence of multiple copies of the hsp70 family in the genome. Increased expression of hsp70 was observed in fourth instar larvae exposed to 42°C. No significant up-regulation of hsp70 expression was observed when fourth instar larvae were treated with sub-lethal doses of insecticides, chlorfenapyr, permethrin, and acephate. These results suggest that hsp70 cloned in the present study is less sensitive to insecticides.

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The ambrosia beetle Platypus quercivorus causes mass mortality of fagaceous trees throughout Japan. Previous studies demonstrated low levels of P. quercivorus attack on both thinner trees and re-attacked trees with previous infection history. To determine the causes of the low levels of attack on these trees, the patterns of attack by P. quercivorus were investigated in 35 Quercus crispula trees for two consecutive years. Logistic regression analysis indicated a significant positive effect of tree size on the probability of male beetle flying to trees, although previous infection history was not selected as an explanatory variable in the model. Tree size and previous infection history exhibited significant positive and negative effects, respectively, when both were selected as explanatory variables in a model predicting the probability of male beetle boring holes in trees. These results suggest that P. quercivorus disregards thinner trees, and flies away from trees with previous infection history after approaching.

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Developmental parameters and photoperiodism in Trigonotylus tenuis (Reuter) (Heteroptera: Miridae) were examined using wheat seedlings as food. The thermal threshold and effective cumulative temperature were 12.5°C and 91.9 day-degrees in the egg stage, 12.7°C and 155.8 day-degrees in the nymphal stage, and 11.7°C and 49.7 day-degrees in the preoviposition stage. Mean longevity of female and male adults at 25°C was 18.4 and 22.8 days, respectively, and a female adult laid 203 eggs on average. A temperature-dependent long-day photoperiodic response was observed in the maternal induction of egg diapause. At 17.5, 20 and 22.5°C, females showed a clear response to the photoperiod with a critical daylength of around 12.5 h/day; females reared under short-day conditions laid diapause eggs whereas those reared under long-day conditions laid nondiapause eggs. At higher temperatures (25, 27.5 and 30°C), however, females responded little to the photoperiod, irrespective of which they laid a high percentage of nondiapause eggs. Based on comparisons with T. caelestialium, a species closely related to T. tenuis, this photoperiodism is considered to be an adaptation to southern climates.

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The olfactory responses of adult males and females of the fruit-piercing moth, Oraesia excavata, to lactones as specific components among ripe peach fruit odors were recorded by electroantennogram (EAG) techniques and trap captures in the field. Six lactones (γ-hexalactone, γ-octalactone, δ-octalactone, γ-decalactone, δ-decalactone and γ-dodecalactone) and a green leaf volatile compound (cis-3-hexen-1-ol) as the reference compound for normalization were used to measure EAG responses. The EAG response to γ-hexalactone, shown to be the highest among the six lactones tested, did not reach as high as that to a mixture of five lactones when 10% concentrations (v/v) of the lactones were used. There was no significant difference between males and females in EAG responses to those compounds. In the field experiment, the number of moths captured by traps baited with a mixture of the five lactones (γ-hexalactone, γ-octalactone, γ-decalactone, δ-decalactone and γ-dodecalactone=142 : 7 : 145 : 70 : 28, v/v) was about half that captured with ripe peach fruit; however, the moths were not captured by traps with individual lactones. These results show that O. excavata is attracted by a mixture of lactones, but not by individual lactones, although individual lactones are recognized by antennal receptors.

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Effects of the antiparasitic drug moxidectin were studied in laboratory and field experiments in Hokkaido, Japan by pour-on administrations (500 μg/kg) on a target pest Haematobia irritans Linnaeus, nontarget coprophagous flies represented by Neomyia cornicina (Fabricius), and the dung beetle Caccobius jessoensis Harold. The concentration of moxidectin excreted into cattle dung was maximum at 3 days post-treatment both in the first and second trials, and then it diminished. No moxidectin was detected on or after day 21 post-treatment in the first trial, and on or after day 28 post-treatment in the second trial. Larval development of H. irritans was hampered from 1 to 7 days post-treatment. No N. cornicina pupated in dung at days 1 and 3 post-treatment, and pupation and emergence rates were reduced in the dung until 7 days post-treatment. There were no significant differences in numbers and weight of brood balls constructed by Caccobius jessoensis in dung from treated and control cattle. Adult emergence rates of C. jessoensis on days 1, 3, 7, 14 post-treatments were not significantly different between control and treated groups, and more than 90% of adult emergence rates were demonstrated in both groups. In the field study using emergence traps, 3,433 (18 families) flies emerged from dung from untreated control cattle and 1,667 (16 families) flies emerged from dung from treated cattle. Notably, the number of Sciaridae spp. (first Experiment) and Sepsis latiforceps Duda and Sphaeroceridae spp. (second Experiment) significantly decreased in dung pats of treated cattle. From 48 dung pats in the field experiments, total dry weight of major coprophagous flies that emerged was 1,741.8 mg in dung from control cattle and 1,170.0 mg in dung from treated cattle, showing 32.8% reduction in treated dung. Emergence rates of C. jessoensis from brood balls recovered from soil beneath dung pats in the field experiments were not significantly different between dung from control and treated cattle on each sampling day (1, 7, 14, and 21 days) post-treatment.

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Carpophilus marginellus is a candidate pollinator of the subtropical orchard trees cherimoya and atemoya. We investigated the developmental period and adult size of this species at constant temperatures of 18, 20, 25, and 30°C as basic information for mass rearing and release in greenhouses as a pollinator. The photoperiod was 16-h light/8-h dark at all temperatures. The developmental period was shorter and the adult size was smaller at higher temperatures. Mortality was lowest at 25°C and highest at 30°C. The thermal threshold (developmental zero) ranged from 11.9 (female larvae) to 15.6°C (female pupae) among developmental stages and sexes. The thermal constant (total effective temperature) of the period from egg to adult emergence was ca. 292 degree-days.

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The white grub beetle, Dasylepida ishigakiensis, was originally known only in the Yaeyama region, including Ishigaki-jima and Iriomote-jima Islands, of the southern part of the Ryukyu Islands, Japan. At the end of the 1990s, a population was discovered to occur abundantly in sugarcane fields in the Miyako region, including Miyako-jima and Irabu-jima Islands, approximately 90 km northeast of the Yaeyama region. Using specimens collected from these islands, fragments of mitochondrial DNA containing portions of ribosomal RNA, cytochrome c oxidase subunit I, and cytochrome b genes were sequenced. Phylogenetic analyses using the sequences revealed discrete separation into three clades: two comprised exclusively of individuals from Ishigaki-jima and Iriomote-jima, respectively, and the third comprised of individuals from the Miyako region, including both Miyako-jima and Irabu-jima. Separation of the clades by rather long branches suggested that they have been geographically isolated for an evolutionarily long period and indicated that the population in the Miyako region was not established by the recent invasion of insects from the Yaeyama region.

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In Adoxophyes honmai, a population that has developed resistance to a disruptant composed of (Z)-11-tetradecenyl acetate was recognized in Shimada in Shizuoka Prefecture. The sex pheromone components of the resistant population were individually analyzed. The average amounts of (Z)-9- and (Z)-11-tetradecenyl acetates were 40.5 ng and 45.6 ng, respectively, whereas the averages in the susceptible population were 39.9 ng and 15.1 ng. The results suggest that resistant females biosynthesize more (Z)-11-tetradecenyl acetate in order to heighten the ratio of the acetate in the sex pheromone component. A 40 : 60 blend of (Z)-9- and (Z)-11-tetradecenyl acetates was the best of six kinds of lures tested on resistant males. The male response tunes to the sex pheromone blend produced by resistant females. Although no attractiveness has been generally observed in a lure impregnated with only (Z)-9-tetradecenyl acetate, males were attracted to the incomplete lure treated with the mating disruptant in the field. Resistant males supposedly utilize the widespread odor of (Z)-11-tetradecenyl acetate released from mating disruption devices installed in the tea canopy for orientation, while they trace a directional plume of (Z)-9-tetradecenyl acetate emitted from the lure.

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In the Ryukyu Islands of Japan, larvae of the green chafer Anomala albopilosa (Hope) are known as a serious pest of sugarcane. Based on sequences of mitochondrial ribosomal RNA genes obtained from specimens collected in this and adjacent areas, the phylogenetic relationships among local populations and geographic distribution patterns of haplotypic groups were examined. As a result, individuals were divided into five groups of haplotypes (Groups A–E). The shape of the phylogenetic trees suggested that they have been separated for a long period in their evolutionary history. Among the three groups distributed in the Ryukyu Islands, Groups B and D were restricted to the northern Amami region and Yaeyama region, respectively, while the range of Group C extended from the Amami to Yaeyama regions through the Okinawa and Miyako regions and largely overlapped the other two groups. This result was considered to suggest that the insular populations of this species were genetically muddled by the recent expansion of Group C that probably originated in the Okinawa region in the central Ryukyu Islands. Causes of these phenomena are discussed in relation to the food habits of this species and the paleogeography of this area.

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To understand the relationship between juvenile hormone (JH) titers and morphogenetic changes associated with soldier differentiation of the termite Reticulitermes speratus, mandibular length (length between apex and first teeth) of presoldiers induced by various concentrations of JH III (0–320 μg per dish) was measured. Presoldiers were observed when treated with more than 20 μg JH III. Both left and right mandibular lengths were significantly different among differentiated presoldiers treated with different concentrations of JH III. Concentration-dependent effects on mandibular lengths were observed: higher JH III concentrations (160 and 320 μg) caused differentiation in presoldiers with longer mandibles, and lower concentrations (40 and 80 μg) caused differentiation in presoldiers with shorter mandibles. These results suggest that morphogenetic changes specific to soldiers are influenced by JH titers (endogenous JH+applied JH III) in workers. Live soldiers could inhibit presoldier differentiation in R. speratus workers. Interestingly, mandibular lengths of presoldiers induced by JH III were influenced by soldier presence, which could influence morphological changes, probably by regulation of JH titers in workers, as recently shown in the termite Coptotermes formosanus.

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