During field applications of Beauveria bassiana for control of Monochamus alternatus larvae living in dead pine trees, differences of mortalities by application date could not be analyzed due to variability in timing of oviposition. To solve this problem, pine logs with eggs of the same age were obtained by exposing logs to female beetles for one day in a screened cage in July or August. Nonwoven fabric strips impregnated with B. bassiana cultures were applied to the logs in September. Infection rate by B. bassiana was higher among larvae from eggs laid in August compared with those from eggs laid in July. Among the logs oviposited on the same day, the infection rate was higher in those with 4 strips/2 m than those with 1.5 strips/2 m. The results of the experiment showed that control of M. alternatus by applying nonwoven fabric strips with B. bassiana was more effective when the fungus was applied to young larvae located under the bark instead of older larvae further within the wood.

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Life-history traits of the Kanzawa spider mite, Tetranychus kanzawai, were assessed and compared with those of the closely related species, T. parakanzawai. This was done by determining the intrinsic rates of natural increase, r_m, of three strains of T. kanzawai and one strain of T. parakanzawai, on leaf discs from each of the four host plants (collected plants) as well as one of suitable hosts for T. kanzawai, mulberry. The r_m-values of the three T. kanzawai strains varied largely from 0.187/day to 0.283/day, and the r_m's on the collected hosts (tea, hydrangea and Japanese pear) were 0.043–0.096/day lower than on mulberry. The r_m of the T. parakanzawai strain was only 0.008/day lower on the collected plant (kudzu vine) than on mulberry. These results seem to suggest that tea, hydrangea and Japanese pear are poor-quality plants for T. kanzawai when compared to their performance on mulberry.

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The development and oviposition of three predacious insects, Stethorus japonicus, Oligota kashmirica benefica, and Scolothrips takahashii, reared on different species of spider mites were studied at 27°C: 16L8D. Eggs and deutonymphs of three species of spider mites, Panonychus mori, Tetranychus urticae, and Amphitetranychus viennensis, which are pest species on Japanese pear, were provided as the prey for the predacious insects. The quality of each spider mite species as prey differed markedly among the three predacious insect species. Both the development and oviposition of S. japonicus differed greatly with the prey species. A. viennensis was a superior prey for both development and oviposition, while P. mori was not. In particular, most larvae reared on P. mori eggs died during the first stadium and only about 10% of larvae developed to pupae. Most larvae of O. kashmirica benefica reared on P. mori eggs also died during the first stadium. However, their development and oviposition were not greatly affected by the difference in prey species. S. takahashii developed and oviposited well regardless of the prey species examined, except that larvae reared on P. mori deutonymphs required more time to complete development.

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Resistance to pyrethroids in the diamondback moth (DBM), Plutella xylostella, has been shown to be conferred by nerve insensitivity. In the present study, amino acid sequences corresponding to the domain IIS4–IIS6 region of the para-sodium channel, which is known to be significant for nerve insensitive pyrethroid resistance in a variety of insects, were compared between pyrethroid-resistant (R) and non-selected (NS) strains. Thr to Ile and Leu to Phe substitutions were identified in R strain at the IIS5 and IIS6 regions, respectively. Although the resistant Ile and Phe residues were also shared by the NS strain at the same amino acid positions, frequency of the resistant amino acid residues in the population was lower than that in the R strain. Amino acid sequences corresponding to the domain IS6 region and the linker region of the domains III–IV, which were recently shown to be involved in the pyrethroid resistance in particular lepidopteran insects, were also compared between the R and NS strains. However, no amino acid substitution was observed in the R strain at either region. These results suggest that Thr to Ile and Leu to Phe substitutions in the domain IIS4–IIS6 were associated with the pyrethroid resistance in DBM.

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Population changes of the mulberry tiger moth, Thanatarctia imparilis (Butler) (Lepidoptera: Arctiidae) and its carabid predator, Parena perforata (Bates) (Coleoptera: Carabidae) were surveyed at three disjunct study sites in the Kinki region, western Japan, from 1989 to 2001. At one of the three study sites, the population density of T. imparilis increased gradually, thereafter, decreased drastically, and then increased again. At this site, the number of P. perforata per prey colony changed closely with the density of T. imparilis. During the decline phase of T. imparilis, P. perforata was observed in over 80% of the prey colonies, and many egg masses of the beetle were deposited on each prey colony. It was observed that the effect of the predation acted strongly during the decline phase of T. imparilis. At another site, moreover, P. perforata was observed in over 80% of the prey colonies during the period of population decline of T. imparilis. At the third site of the three, however, the carabid beetles were observed in less than 10% of the prey colonies even during the decline phase of T. imparilis. At this site, the population density of T. imparilis decreased after high density had persisted for a few years and started to increase after low density had persisted for a few years. In addition, the change in amplitude between the highest density and the lowest density was ca. one-third that at the other two sites. It was suggested that the predator-prey interaction constitutes an important factor in explaining the different behaviors of T. imparilis populations at different localities.

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Papilio polytes, a Rutaceae feeder, exploits only a few plant species as larval food plants in nature. To clarify the physiochemical factors underlying its narrow host range, we examined the acceptability of four rutaceous plants, Citrus depressa (a host plant) and other potential hosts, Fagara ailanthoides, Evodia meliifolia, and Orixa japonica, to ovipositing females of the butterfly. Female responses to the foliage, methanol extracts and partitioned fractions prepared from these plants were assayed for the presence of oviposition stimulants and/or deterrents. The foliage and methanol extracts of C. depressa and F. ailanthoides readily induced egg-laying, while those of E. meliifolia evoked weak responses from females. In contrast, ovipositing females never accepted O. japonica. Further experiments with fractions derived from the respective plants revealed that C. depressa and F. ailanthoides contained potent oviposition stimulant(s) and E. meliifolia, both moderate stimulant(s) and weak deterrent(s). Negative oviposition response to O. japonica proved to be ascribed to the presence of weak deterrent(s) and the lack of any appreciable stimulant(s). Larval survivorship on these plants was also recorded as an estimate of fitness. In good coincidence with female oviposition responses, both 1st- and 5th-stadium larvae performed well on C. depressa and F. ailanthoides, while larval performance appeared a little worse on E. meliifolia. On the other hand, the survivorships of two larval stadia on O. japonica differed greatly from each other: whereas the mortality of neonates was very high, 5th stadium larvae grew into pupae as well or better on this plant as compared to E. meliifolia. These results suggest that the four rutaceous plants are arrayed as follows in decreasing order of acceptability: C. depressa=F. ailanthoides>E. meliifolia>>O. japonica.

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Recently, crop damages by the cabbage webworm, Hellula undalis Fabricius (Lepidoptera: Pyralidae), has been frequently observed in Japan, and the development of a species-specific trap for monitoring of the field population is required. Unfortunately, the attraction activity of the known sex pheromone of this species, (E,E)-11,13-hexadecadienal, is too weak to be effective in a lure for this trap. Thus, we began field screening tests to find compounds that could enhance the attraction activity of (E,E)-11,13-hexadecadienal. In the tests, we found that a mixture of 5 μg of (E,E)-11,13-hexadecadienal and 15–500 ng of (Z)-11-hexadecenal showed the same attraction activity as virgin females. The existence of this compound was not confirmed in the extract of virgin females.

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The sequence of acetylcholinesterase (AChE) cDNA from the diamondback moth (DBM), Plutella xylostella (L.) was determined. A 2.3 kb partial cDNA sequence, containing an ORF encoding AChE precursor with 638 amino acid residues was obtained by primer walking. The deduced protein sequence showed the highest homology to AChE of the Colorado potato beetle (CPB) and the green rice leafhopper. The DBM AChE belongs to the Drosophila melanogaster Ace-orthologous insect AChE subfamily. A single AChE gene transcript (7.6 kb) was detected by Northern blot analysis. This is the first report of the complete coding sequence of AChE cDNA from a lepidopteran insect.

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Energy dynamics of a natural population of the cotton bollworm, Helicoverpa armigera, was investigated using a combination of field surveys and a laboratory energy budget experiment. The ingestion and production of the population (during generations 2nd–4th) were 29.59 kJ/m² and 2.69 kJ/m², respectively. The assimilation efficiency ranged from 64.67 to 75.72%, and the net ecological efficiency was 9.21–16.21%. Of the fruit production of cotton plants, 0.17% was consumed and 9.80% damaged by the bollworm population over the entire study period. Both percentages were significantly higher in the 2nd generation than those in the 3rd and 4th generations. This work provides strong evidence that H. armigera is a major pest in a cotton agroecosystem in North China, and the second generation was the key damage-causing generation.

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We investigated the effects of temperature and photoperiod on development and oviposition of Frankliniella occidentalis. Even though the developmental periods of eggs, larvae and pupae were shorter at 20°C than at 15°C, no significant difference in the developmental periods was observed between long photoperiod (16L:8D) and short photoperiod (10L:14D). The longevity of adult females was longer under short photoperiod than long photoperiod at 15°C. Fewer eggs were laid per female per day under short photoperiod than long photoperiod at 15°C, but no significant difference in the total number of eggs was observed between the two photoperiods. Furthermore, average pre-oviposition periods under short photoperiod were similar to those under long photoperiod at the same temperatures and adult females continuously oviposited at 15°C under both photoperiods. These results indicate that the F. occidentalis tested undergoes no reproductive diapause under short photoperiod.

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The electronic monitoring system (EMS) has been used for measuring the feeding behavior of numerous piercing-sucking insects. Although it has also been used for measuring that of chewing-type insects, waveform patterns have not been analyzed in detail. Therefore, we measured the feeding behavior of Plutella xylostella larvae by using a computer-based EMS to correlate between waveforms and behavioral events accurately and efficiently. In this study, we confirmed four distinctive waveforms that related to feeding, walking and resting of P. xylostella larvae on cabbage leaves. Furthermore, from detailed waveform analysis, it was suggested that chewing frequency of P. xylostella larvae correlated to the number of minute pulses in the waveform during feeding. These results show that a computer-based EMS is a useful tool for analyzing feeding behavior of chewing-type insects such as P. xylostella larvae.

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Sex pheromone of the flax budworm, Heliothis maritima adaucta, was extracted from abdominal tips of virgin females using hexane. Three EAD-active peaks were detected in the extract by the GC-EAD method. These peaks were identified to be (Z)-11-hexadecenal (Z11-16:Ald), (Z)-11-hexadecen-1-ol (Z11-16:OH), and n-hexadecanal (n-16:Ald) by GC-MS analysis. The ratio of Z11-16:Ald, Z11-16:OH, and n-16:Ald was 100 : 24.5 : 2.4, and the amount of Z11-16:Ald was about 18.1 ng per female. Mixtures of Z11-16:Ald and Z11-16:OH in ratios of 100 : 1–6 attracted males in the field, but the each compound alone did not. White rubber septa impregnated with 1.01 mg and 3.03 mg of a mixture of Z11-16:Ald and Z11-16:OH in a ratio of 100 : 1 could capture more males than those with smaller doses. Addition of n-16:Ald to binary mixtures did not increase their attraction activity. Therefore, Z11-16:Ald and Z11-16:OH were concluded to be essential components of the sex pheromone of H. m. adaucta for male attraction. Also, addition of (Z)-9-hexadecenal, a pheromone component in a subspecies in Hungary, to the above binary mixture did not increase the attraction activity.

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To evaluate the effectiveness of an egg parasitoid, Trichogramma chilonis Ishii, in suppressing numbers of the diamondback moth (DBM), Plutella xylostella (L.), three types of experiments, the response of T. chilonis to host density within a plant, the response of T. chilonis to host density among plants, and the fluctuation of DBM populations with and without T. chilonis, were carried out in a laboratory and in a greenhouse. T. chilonis attacked more host eggs as their density increased. The number of eggs parasitized was higher and the variation in the parasitism was lower when the number of parasitoids released was larger. However, the number of parasitized eggs per parasitoid decreased as the number of parasitoids released increased. Results of releasing experiments in the greenhouse showed that the behavior of parasitoids toward the DBM eggs is nearly random. A multiple regression analysis suggested that to realize 80 percent parasitism, the release of more than 60 parasitoids per plant is required. The release experiments indicated that T. chilonis has a suppressive effect on DBM density.

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The fluorescent brightener Tinopal UNPA-GX enhanced the infectivity of a Mythimna separata nucleopolyhedrovirus (MyseNPV) in Mythimna separata (Walker) (Lepidoptera: Noctuidae) when larvae were perorally inoculated with a mixture of 1% of this brightener and occlusion bodies of MyseNPV. However, the infectivity was not enhanced when M. separata larvae were injected with a mixture of 1% Tinopal UNPA-GX and budded viruses of MyseNPV, suggesting that Tinopal UNPA-GX acts in the gut, not in the hemocoel. Peroral ingestion of Tinopal UNPA-GX resulted in a quick degradation of the midgut peritrophic membrane (PM) in M. separata larvae. Twenty-four hours after ingesting Tinopal UNPA-GX, the PM was fully regenerated. In addition, larval susceptibility to MyseNPV one day after ingesting the brightener did not differ significantly from that of larvae inoculated with the virus alone. These results suggest that Tinopal UNPA-GX facilitates the infectivity of MyseNPV by altering the structural integrity of the PM.

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The effect of constant temperature on the development, reproduction and population growth of Aculops lycopersici reared on a tomato leaflet was investigated. Survival rates from egg to adult were more than 69% at temperatures between 15°C and 27.5°C, but only 53% at 30°C. Developmental rates increased linearly as rearing temperature increased from 15°C to 27.5°C. A total of 81.2 degree-days above a developmental zero of 10.5°C were required to complete development from egg to adult emergence. Adult longevity decreased with increasing temperature. Fecundity was highest at 25°C with 51.7 eggs per female. The highest intrinsic rate of natural increase was observed at 25°C as 0.253 per day.

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The developmental and reproductive characteristics of the pyrrhocorid Antilochus coqueberti, a specific predator of Dysdercus spp., were examined in the laboratory and observed in the field on Ishigaki-jima Island. A. coqueberti fed D. cingulatus exhibited normal development in temperature regimes between 20°C and 30°C and a long photoperiod of 14L–10D, but rearing was unsuccessful under temperature regimes of 15°C and 17.5°C. A lower threshold temperature for development and effective cumulative temperatures for development of the eggs and nymphal stadia were estimated to be 12.9°C and 607.5 degree days, respectively. A. coqueberti did not exhibit reproductive diapause, even when reared under a short photoperiod of 10L–14D. Both the nymphs and adults of A. coqueberti were observed almost all year round on Ishigaki-jima Island. These results indicate the absence of a reproductive diapause provoked by a short photoperiod in this species. High fecundity and the absence of a reproductive diapause are desirable for artificial mass rearing of this insect for use as a predaceous natural enemy against Dysdercus bugs. Temperature regimes between 22.5°C and 27.5°C are recommended for artificial rearing, because of the relatively low mortality seen under these temperature regimes.

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Volatiles from lima bean leaves heavily infested with the herbivorous spider mite, Tetranychus urticae, attracted the carnivorous mite, Phytoseiulus persimilis, and repelled T. urticae over volatiles from uninfested leaves. Significantly more herbivore-induced volatiles were emitted from heavily infested leaves than from slightly infested leaves. When leaves were moderately infested, the amount of induced volatiles was intermediate between those of heavily infested and slightly infested leaves. These volatiles attracted P. persimilis, but neither attracted nor repelled T. urticae more than uninfested leaves. When leaves were slightly infested with T. urticae, small amounts of induced volatiles were detected. These volatiles neither attracted nor repelled P. persimilis more than uninfested leaves, but attracted T. urticae more than uninfested-leaf volatiles. The volatiles from lima bean leaves that were slightly or heavily infested with the herbivorous lepidopteran, Spodoptera exigua, neither attracted nor repelled T. urticae or P. persimilis. Most of the volatile compounds emitted from leaves heavily-infested with S. exigua were the same as those emitted from T. urticae-infested leaves, but the blend of the volatiles differed with the infesting species. The functions of volatiles emitted from herbivore-infested leaves are discussed in terms of herbivore density and their specificity.

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The effects of photoperiod and temperature on developmental and larval diapause of Dacne picta (Coleoptera: Erotylidae) were observed by rearing beetles on dried basidiocarps of shiitake mushroom, Lentinula edodes, under various environmental conditions in the laboratory. The theoretical lower thermal threshold and thermal constant for egg, larva and pupa were 12.0°C and 47.7 day-degrees, 7.3°C and 456.1 day-degrees and 5.9°C and 139.1 day-degrees, respectively. Diapause was induced in the 4th larval stadium under shorter daylength than 14 h and 13 h at 20°C and 25°C, respectively, and averted at a photoperiod ≥13.25 h at 20°C. The heat requirement indicated that the beetle may complete three generations per year in Tsuchiura, Japan (36°05′N, 140°10′E).

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Termites, Reticulitermes speratus Kolbe, reared individually were highly susceptible to the entomopathogenic fungus Metarhizium anisopliae. In contrast, termites reared in groups were highly resistant to M. anisopliae. When reared in groups, the termites treated with M. anisopliae conidia on the body surface were groomed by their nestmates and more than 90% of the conidia were removed from the cuticle within 3 h. However, the conidia affiliated with the termites reared individually did not show a marked reduction. Within 3 h, almost all of the termites held in groups contained the conidia in their foreguts, but no conidia were detected in the foreguts of the termites reared individually. These data suggest that one of the functions of grooming by nestmates is the removal of foreign bodies, such as fungal conidia, from the cuticle and the mutual grooming behavior is very effective in protecting them from M. anisopliae infection.

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Parasitism by tachinid parasitoid(s) was investigated for 7 species of lepidopteran host larvae collected in Ibaraki Prefecture, Japan in 1997 and 1998. A total of 188 tachinid larvae emerged from 157 out of 1, 051 field-collected hosts. Compsilura concinnata (Meigen), Exorista japonica (Townsend), Pales pavida (Meigen), Senometopia excisa (Fallén), Zenillia libatrix (Panzer), Blepharipa sp. and Exorista spp. were identified. New hosts of E. japonica, P. pavida and Z. libatrix were recorded. Emergence of more than 1 conspecific larva from a single host individual was observed in hosts parasitized by E. japonica, P. pavida, S. excisa or Blepharipa sp. Three different types of species combinations in multiparasitism were also observed: (1) E. japonica and P. pavida; (2) E. japonica and Tachinidae sp.; and (3) Blepharipa sp. and Tachinidae spp. These results suggest that E. japonica, P. pavida, S. excisa and Blepharipa sp. larvae potentially have a high “tolerance” for the presence of other tachinid larvae. Probably, this enables these tachinid larvae to coexist tolerantly with conspecific and/or heterospecific tachinid larvae and, therefore, benefits their survival when there are not sufficient hosts available.

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We observed the mating behavior of Monochamus saltuarius (Cerambycidae: Lamiinae) and confirmed the following behavioral actions. The male reacted to the female with his antennae or tarsi, the male dashed to the female and mounted her back. Copulation consisted of three phases: First, while bending at the abdomen, the male inserted his penis into the female's genitalia, second, the male is motionless with the females genitalia being pulled out from her abdomen by the males penis, outside of both body cavities, finally, the male tries to pull out his penis from the female genitalia. The copulation was shown to take place mostly for one and a half minutes, with a significant tendency to be slightly shortened as the pair progressed from the first through the third copulation. The violent fight between two males took place in the presence of a female and sometimes she changed her mate. The male did not differentiate between dead and live females, because the male mounted dead females as same as live them.

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By a grading method, we classify the infestation level into grades depending on the number of individuals and record the grade of infestation without recording the number of individuals. However, the resultant grade has no clear meaning and hence it currently has only limited use. There are two questions that should be solved to construct a grading method that yields a meaningful grade. (1) Which scale should we use to determine the boundary of grades? For example, is a logarithmic scale such as that divided at x=1, 10, 100, 1000 preferable to an arithmetic scale such as that divided at x=50, 100, 150, 200? (2) Which grade width should we use? When we use a logarithmic scale, for example, is a 5-times width such as that divided at x=1, 5, 25, 125 preferable to a 10-times width such as that divided at x=1, 10, 100, 1000? For the first question, we suggest that we should utilize the scale that improves homoscedasticity to perform ANOVA. For the second question, we provide a procedure to determine the optimal grade width.

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Responses of Diadegma semiclausum, a specialist solitary parasitoid of diamondback moth (Plutella xylostella) larvae, to host-infested cabbage plants were studied. Females were more attracted to host-infested plants than uninfested plants in a wind tunnel. The origin of the attraction was neither the hosts nor their associated products, such as feces, silk and exuviae, but the infested plant itself. Once on the infested plant, the females initiated specific antennal contact with a host-damaged site on a leaf to search for hosts. Based on these data, the effect of chemical cues from infested plants on host searching by females is discussed.

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