We reared two aphidophagous syrphid species, Episyrphus balteatus and Eupeodes bucculatus, on artificial diets throughout all larval stages but their development was inferior to those feeding on natural prey (aphids). Drone honeybee brood powder (DP) offered the minimum nutrition necessary for larval development in both species. E. balteatus grew to adulthood on the original DP diet, but E. bucculatus did not. An agar-gel diet containing DP improved the survival rate of E. bucculatus and half the larvae on this diet reached adulthood. Diet softness was a very important physical factor for rearing syrphid larvae. The amount of food consumed by third-instar larvae of E. bucculatus was measured. The results showed sufficient intake of DP by the larvae. The addition of autolyzed yeast and sucrose to the diet improved larval development.

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Empirical studies reveal that dispersal behavior is dependent on local population density in different wild animals. Theoretical studies also pay much attention to modeling dispersal strategies sensitive to population density; however, the evolution of sex-biased dispersal has not been analyzed sufficiently by a model considering density-dependent dispersal. Therefore, a previous model where it is assumed that only genetic factors determine an individual's dispersal timing was thoroughly modified. The resultant model assumes that dispersal timing is determined by the interaction of genetic factors with local population density and local habitat size. This model demonstrates that when females copulate before dispersal, they evolve to emigrate from their natal habitat earlier than males. A model where dispersal timing is dependent on the local sex ratio instead of population density was also analyzed. This model also results in the evolution of female early dispersal, but the resultant dispersal timing of both sexes is slightly different from the model sensitive to population density. This difference is related to sexual difference in factors affecting reproductive success. Local population density is associated with the intensity of resource competition among females, whereas local sex ratio is informative for mate competition among males.

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The distribution of two small coccinellids, Phymatosternus lewisii and Scymnus posticalis, across colonies of the aphid Toxoptera citricidus in relation to ant-attendance of the colonies and ant species, behavioral interactions between the coccinellid larvae and ants, and the overlap in the larval distribution of the two coccinellids were examined in a citrus grove in Japan. P. lewisii larvae were found frequently in aphid colonies attended by the ant Pristomyrmex pungens but rarely in colonies attended by another ant, Lasius japonicus, and in ant-excluded colonies. A number of S. posticalis larvae were also recorded in P. pungens-attended colonies and some larvae in ant-excluded colonies. A few P. lewisii adults were noted only in P. pungens-attended colonies, whereas some S. posticalis adults were observed in ant-excluded colonies. In most encounters, P. pungens workers tapped P. lewisii larvae with their antennae but showed no aggressive behavior; otherwise, P. pungens workers ignored the larvae. P. pungens exhibited the same behavior when encountering S. posticalis larvae. The proportion of P. pungens-attended aphid colonies where the larvae of both coccinellids occurred did not significantly differ from the probability of both coccinellids occurring in the same colonies given their random distribution across the colonies. Thus, larvae of the two coccinellids exploited aphid colonies attended by a particular ant, P. pungens, and the larval distribution of the two species may be independent of each species.

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The preimaginal development of Chrysocharis pubicornis was studied at different temperatures and 14L:10D photoperiod. The lower developmental threshold was 7.4 and 7.2°C, and the thermal constant was 297.4 and 307.5 degree-days for males and females, respectively. The effects of combinations of different temperatures and photoperiods on larval diapause induction and termination were also examined. Larval development showed a short-day type response affected by temperature. The percentage of individuals entering diapause increased with the temperature and photoperiod. The critical photoperiod for diapause induction was between 12 and 14 h at 25°C, whereas at 15 h and 20°C the diapause rate did not reach 50% within the photoperiod range tested. Regardless of the photoperiod, diapause terminated at 15°C but was maintained at 25°C. At 20°C, 90% of individuals terminated diapause at 12 h photoperiod but only 16% at 16 h photoperiod. A significant effect of the photoperiod on the post-diapause emergence pattern of wasps was observed at 15°C. From these results, it is considered that summer diapause enables C. pubicornis to synchronize its occurrence with that of the garden pea leafminer, Chromatomyia horticola.

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We investigated induced resistance to the common cutworm, Spodoptera litura, in three soybean cultivars, ‘Bay’, ‘Fukuyutaka’, and ‘Himeshirazu’. Levels of induced resistance caused by S. litura herbivory varied among the cultivars. High induced resistance was found in ‘Bay’, with less food consumption by larvae (78.2%), less larval weight gain (67.3%), longer larval duration (114.2%), and lighter pupal weight (79.7%) than on uninjured plants (100%). The same trends were observed in larvae feeding on leaves of previously damaged plants of ‘Fukuyutaka’, which is susceptible to S. litura, but only larval duration was significantly prolonged (107.3%). No apparent effect of previous herbivory on plants was found in ‘Himeshirazu’, which is constitutively resistant to S. litura. Prior mechanical injury to leaves of ‘Bay’ also decreased subsequent food consumption by larvae (82.9%), but had little effect on larval growth.

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Intensive and successive field surveys on the relative abundance of Nezara viridula (Hemiptera: Pentatomidae) and N. antennata at various localities in northern Kyushu, Japan, together with scattered collection records of N. viridula in Kyushu and Honshu, clearly showed that N. viridula has been expanding its range northward since the 1960s. The present range of N. viridula in Kyushu coincided well with the areas where the mean temperature of the coldest month exceeds 5°C that has been suggested to be the lowest thermal limit for N. viridula to overwinter successfully. The future range of N. viridula is predicted to cover a large area of Kyushu if the temperature rises by 1.4 to 5.8°C by 2100. In some places, N. antennata seemed to have been replaced by N. viridula as a result of their interspecific mating that prevented N. antennata from intraspecific mating. This is because N. antennata was overwhelmed, in abundance, by N. viridula, which has a higher reproductive potential than N. antennata under warm conditions with a sufficient amount of food resources. Conversely, N. antennata populations recovered in a few places where N. viridula had replaced N. antennata in the 1950s, probably due to the shortage of rice plants on which N. viridula preferably reproduces.

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We examined the usefulness of five properties of gall size as alternative measures of true gall fitness, defined as the number of alates that emerged from a gall, in four species of Nipponaphidine galling aphids (Neothoracaphis yanonis, Metathoracaphis isensis, Monzenia globuli, and Dinipponaphis autumna). Among five properties (short diameter, long diameter, height, ellipsoidal volume, and ellipsoidal surface area), we determined that surface area was the most accurate and practical measure of gall fitness. This measure is particularly useful for obtaining a sufficient number of gall samples from reared species and species that experience high levels of predation. We also discuss other measures of gall fitness and various problems associated with them.

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The cold hardiness in adult males and females of Frankliniella occidentalis (Pergande) reared at different conditions were investigated. Supercooling points (SCPs) were about −26°C in both males and females. The SCPs were not affected by the rearing conditions of photoperiod and temperature. However, the survival periods of males and females at low temperatures from −15°C to 5°C were predominantly affected by rearing temperatures. Males and females reared at 15°C survived longer at the low temperatures than those reared at 20°C. Females survived for much longer than males at the low temperatures except −15°C. Furthermore, the survival periods of males and females at the low temperatures were affected by water and food applications. However, the effects were smaller in both males and females at 0°C from −5°C for 12 h to +5°C for 12 h than 5°C, especially less water effect was observed in males at 0°C. Males and females given food maximally survived for about 30 d and 40 d at 0°C, and about 40 d and 60 d at 5°C, respectively. These results show that F. occidentalis can overwinter only in relative mild winter or artificial conditions.

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Gall midge pests (Diptera: Cecidomyiidae) intercepted under plant quarantine inspection at Japanese sea- and airports from 2000 to 2005 were identified based on the morphological features of full-grown larvae and adults. We identified the following 17 species from 13 plant genera: Contarinia maculipennis Felt on Dendrobium phalaenopsis (Orchidaceae) imported from Thailand and Singapore, Contarinia sp. 1 on Brunia (Bruniaceae) from South Africa, Contarinia sp. 2 on Berzelia (Bruniaceae) from South Africa, Contarinia sp. 3 on Alstroemeria (Alstroemeriaceae) from Australia and New Zealand, Contarinia sp. 4 on Azadirachta (Meliaceae) from Thailand, Contarinia sp. 5 on Juniperus (Cupressaceae) from Turkey, Dasineura sp. 1 on Pinus (Pinaceae) from China, Dasineura sp. 2 on Eurya (Theaceae) from China, Monarthropalpus flavus (Laboulbène) on Buxus sempervirens (Buxaceae) from Italy, Resseliella sp. 1 on Juniperus from Turkey, Resseliella sp. 2 on Protea (Proteaceae) from South Africa, Schizomyia sp. on Caustis (Cyperaceae) from Australia, Thecodiplosis sp. on Pinus from China, Asphondyliina gen. sp. on Eurya from China, Cecidomyiini gen. sp. 1 on Eurya from China, Cecidomyiini gen. sp. 2 on Ischyrolepis (Restionaceae) from South Africa, and Schizomyiina gen. sp. on Cotinus (Anacardiaceae) from Italy. The monthly interception frequency of gall midges associated with Brunia was significantly correlated with the number of imported Brunia cut flowers in different months, but the interception frequencies of gall midges associated with Dendrobium and Eurya were not correlated with the number of imported host plants. Gall midges associated with Pinus were frequently intercepted in December when a huge number of Pinus twigs were imported, while no significant correlation was detected between the interception frequency of gall midges and the number of imported Pinus twigs based on data from January to November.

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Facultative parthenogenesis, or condition-dependent alternation of sexual and asexual reproduction, is widespread in animals. Parthenogenesis enables unmated females to reproduce and thus has a great adaptive significance, especially under low pairing efficiency. In the termite Reticulitermes speratus Kolbe, females that fail to pair with males found colonies cooperatively with partner females and reproduce parthenogenetically. We compared the quality of parthenogenetic and sexual eggs in terms of size, hatching rate, and hatching period. We developed a method to culture isolated eggs until hatching under sterile conditions and in appropriate humidity. We successfully isolated, sterilized, and maintained the eggs on agar plates containing 200 ppm tetracycline. Females of female-female (FF) pairs began to lay eggs at the same time as those of female-male (FM) pairs. Nevertheless, the parthenogenetic eggs were significantly larger than sexual eggs. While the two types of eggs had similar hatching rates, parthenogenetic eggs had longer hatching periods (36.36±0.16 [SE] days) than sexual eggs (34.95±0.12 SE). We conclude that primary queens invest more resources into each parthenogenetic egg than each sexual egg, and that parthenogenetic eggs are as viable as sexual eggs.

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Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) pattern of heat-shock protein 70A gene (hsp70A) was examined for 29 isolates of the pinewood nematode. Among them, two known avirulent and five virulent isolates generated banding patterns identical within each of the two isolate groups but distinctive between the two. On the other hand, field populations were collected in two geographical areas, around Kasama City, Ibaraki Prefecture and the southern part of Kujukurihama coast, Chiba Prefecture, Japan. PCR-RFLP image analysis revealed that some of the populations possessed both of the two alleles. The geographical distribution of the alleles was random in the two sampling areas. On the basis of the results, we hypothesize that the avirulent strain might have a certain contribution to the gene pool of the pinewood nematode, although there has been no report on the collection of an avirulent population from Japan recently.

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Chemical components that attract males in the laboratory were extracted from the female elytra of the white-spotted longicorn beetle, Anoplophora malasiaca (Thomson) (Coleoptera: Cerambycidae), and found to be comprised of several sesquiterpene hydrocarbons. Males located females that had fed on the bark of the host plant Citrus unshiu more frequently than those fed on an artificial diet in the laboratory. Male attraction was also confirmed in the corresponding sesquiterpene fractions of the host plant. The sesquiterpene fractions of female elytra and C. unshiu leaves showed quite similar GC profiles. In the field, the beetles were found on C. unshiu trees baited with intact females or males as frequently as those baited with the leaf extracts containing the sesquiterpenes at different purification levels. The beetles were found on those baited trees significantly more frequently than on unbaited control trees. Males, as well as females attracted both sexes, and the male elytra also contained the sesquiterpenes that were identical with those in female and C. unshiu. This indicated that active components in the elytra are acquired from C. unshiu by feeding, contact and/or adsorption. These sesquiterpenes may serve for intraspecific communication in A. malasiaca. The major sesquiterpenes from the C. unshiu leaves were isolated and elucidated by NMR analyses of four sesquiterpene hydrocarbons, β-elemene, β-caryophyllene, α-humulene, and α-farnesene.

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Solanum fruit fly, Bactrocera latifrons (Hendel) is known as a pest of Solanaceae crops. This species is distributed throughout South-East Asia and has been discovered only on Yonaguni Island in Japan. After its first discovery in 1984 on Yonaguni Island, the species was found in 1985 and 1986, subsequently not detected for twelve years, and again discovered in 1999. We carried out a host fruit survey from 1999 to 2004 to monitor the occurrence of B. latifrons, and confirmed that B. latifrons has repeat generations within Yonaguni Island. During the survey, the number of sites where B. latifrons was found increased gradually, and eventually Yonaguni Island was entirely infested. So far, B. latifrons has not been found on neighboring islands. Most B. latifrons may overwinter at the adult stage on Yonaguni Island. In this survey, Diprocyclos palmatus was first recorded as the host of B. latifrons.

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In 2005, gall midge larvae (Diptera: Cecidomyiidae) were found infesting flower buds of bitter gourd, Momordica charantia (Cucurbitaceae), in Okinawa and orchids, Dendrobium spp. (Orchidaceae), in Fukuoka and Miyazaki Prefectures, Japan. On the basis of morphological features and molecular data of mitochondrial cytochrome oxidase subunit I region, we identified all these gall midges as an invasive species, Contarinia maculipennis, which is a polyphagous pest infesting flower buds of various plant species across seven botanical families. In Japan, it was first detected in 1989 in orchid greenhouses on Okinawa Island. Since then, we have been concerned an injury by the gall midges to bitter gourd in the field because bitter gourd is one of the most important cash crops in Okinawa. Another anxiety has been that it may invade other parts of Japan directly from Southeast Asia. These concerns were realized in 2005. We urgently warn those who are responsible for orchid growing, international trading, and inspection, against the transporting potentially infested plants from country to country and from locality to locality within a country. We also emphasize a necessity to investigate the host range of C. maculipennis in Japan.

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We examined soils of the island Okinoerabu-jima, Kagoshima Prefecture, Japan, for the occurrence of Bacillus thuringiensis. The organism occurred in 13 (65%) out of 20 soil-sampling sites, and 27 (27%) out of 100 soil samples. Among 2,680 Bacillus cereus group colonies examined, 66 were allocated to B. thuringiensis. Soils of the island provided at least 11 H-serotypes. Most of the isolates exhibited no insecticidal activities, while an isolate of serovar kurstaki (H3abc) with bipyramidal parasporal inclusions killed both dipteran and lepidopteran larvae, and another isolate of serovar colmeri (H21) with irregularly-pointed inclusions had a high mosquitocidal activity. None of the seven isolates of serovar israelensis (H14) showed mosquito larvicidal activities, while producing parasporal inclusions morphologically similar to those of the reference strain of serovar israelensis with strong mosquitocidal activities.

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A bioluminescent adenosine triphosphate (ATP) assay for determining viability in adult females of the two-spotted spider mite, Tetranychus urticae, and eggs of the European red mite, Panonychus ulmi, (both diapause and non-diapause state), was investigated. ATP contents in living and dead individual mites (adult females or eggs) were measured. The mites of the lethal treatment group were killed by freezing at −35°C. Mean (±SD) ATP contents for non-diapause and diapause T. urticae female adults were 34.39±5.14 pmol and 26.40±2.67 pmol, respectively. Corresponding values for non-diapause and diapause P. ulmi eggs were 1.12±0.19 pmol and 0.87±0.16 pmol, respectively. ATP contents in living mites in diapause were therefore approximately 77% of those in non-diapause mites. A wide variance in the ATP contents (0.00–0.94 pmol) was found in individual P. ulmi diapause eggs at 2 and 4 h after treatment; therefore, their mean ATP contents did not show a rapid decrease. We speculated that some P. ulmi diapause eggs survived for several hours after treatment by cold hardiness, maintaining metabolic activities until death. However, with the exception of P. ulmi diapause eggs, ATP contents in both mite species rapidly decreased at 2 h after treatment. At 24 h after treatment, ATP contents in both mite species had decreased significantly to 0.4–2.7% of the pre-treatment values, regardless of whether they were in a non-diapause or diapause state. Thus, based on our findings with T. urticae adult females and P. ulmi eggs, the ATP bioluminescence assay could be applicable to the determination of pest viability, regardless of their diapause state.

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RAPD-PCR was used to clarify the genetic properties of the sweet potato weevil, Cylas formicarius, which was collected from several of the Southwest Islands, Ogasawara Islands, Muroto City and Yakushima Island in Japan. PCR amplification of C. formicarius DNA using three primer sets, i.e., T13/T13, T05/T05, and T01/T07, resulted in products of several different sizes among individuals and primer sets. The 393 wild weevils tested were classified into 27 distinctive categories by combining the three patterns detected for each weevil. The frequency of these categories varied both among islands and among collection sites within the same island. The categories confirmed for weevils from Muroto City and Yakushima Island were detected only in those from Okinawa-Hontou Island and the more northern islands of the Southwest Islands. C. formicarius from these islands probably invaded Muroto City in 1995 and Yakushima Island in 1997.

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Overwintering larvae of the rice stem borer, Chilo suppressalis Walker are known to produce endogenous ice nuclei in the muscle and epidermis as a means of avoiding intracellular freeze damage. However, the nuclei are not produced in non-diapausing larvae. To determine the effects of photoperiod and temperature on ice nucleus production, mature larvae were reared at 25°C under short and long photoperiods and acclimated to low temperatures. The ice nuclei were produced only in the muscle and epidermis of diapausing larvae reared under a short photoperiod and acclimated to low temperatures. The production of endogenous ice nuclei in the muscle and epidermis was sufficiently stimulated by short photoperiod and cold-acclimation to explain the crystallization temperature of the overwintering larvae.

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Thrips tabaci Lindeman is an extensively distributed pest insect that injures a wide range of crops. To investigate the intra-specific genetic diversity of this species, we analyzed an 810 bp region of the mitochondrial cytochrome oxidase gene subunit I (COI). Eight populations from six foreign countries and 18 Japanese populations were tested, and 17 different haplotypes were identified. Apparent differences were found between arrhenotokous and thelytokous strains in their COI sequences. A phylogenetic tree of the COI gene shows two distinct groups. We assume that these two groups correspond respectively to the arrhenotokous strain and the thelytokous strain. Japanese thelytokous types consisted of five haplotypes. Two haplotypes were identified from problematic populations in terms of the greater amount of damage they caused and the development of insecticide resistance. Both haplotypes were also found overseas, suggesting that some strains from overseas may have caused the above-mentioned problems in Japan.

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To document the relative abundance of Liriomyza sativae, L. trifolii, and L. bryoniae, the seasonal prevalence of three Liriomyza species infesting commercially grown tomato and cucumber plants was surveyed in four greenhouses in Kyoto Prefecture from 2000 to 2002. In tomato greenhouses, only L. bryoniae was found from April to July 2000 and 2002, but from August to December 2000 and 2002, L. sativae was predominant. Throughout 2001, L. sativae was predominant with a few L. bryoniae. In cucumber greenhouses, only a few L. bryoniae were found from April to June 2002. From August to November 2002, only L. sativae was found, except for one L. trifolii. Additionally, the species composition of the three Liriomyza species infesting commercially grown vegetable plants was occasionally surveyed by collecting full-grown larvae and pupae of Liriomyza found on the foliage of these plants at various locations in Kyoto Prefecture from 1997 to 2002. In 1997 and 1998, only L. trifolii or L. bryoniae was found. In 1999, L. sativae was also collected, but L. trifolii or L. bryoniae was predominant; however, from 2000 to 2002, L. sativae was predominant, and L. trifolii and L. bryoniae populations decreased suddenly.

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There have been independent long-term studies of tobacco-adapted populations of Myzus persicae in Japan and Greece, but until now no direct comparisons have been made between them. In Japan, as in Greece, tobacco aphids can reproduce sexually to some extent so that there is the potential for hybridisation with M. persicae from other plants on their common primary host, the peach. To determine whether Japanese tobacco aphids agree morphologically with those in Greece, and hence fit the concept of M. persicae ssp. nicotianae, multivariate morphometric analysis was applied to 16 clones of M. persicae s.lat. from various localities in Japan. The clones represented 14 different “colour-esterase forms” collected from tobacco and other crops over a 20-year period and kept in laboratory culture. The analysis discriminated most of the clones from tobacco from those collected on other crops. When Japanese samples were analysed together with those from Greece, the tobacco-feeding clones of both countries had a similar pattern of morphometric correlations, discriminating them from those on other crops, even though they were reared under different conditions. Thus, the genomic integrity of M. p. nicotianae seems to be preserved across a wide geographical scale and even in regions where interbreeding can occur. The possible origin and evolution of the tobacco-adapted subspecies are discussed.

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