This mini review focuses on ladybird foraging behaviour with special reference to Coccinella septempunctata (L.) and chemical stimuli. Cues related to aphid finding, such as aphid alarm pheromone, honeydew, and chemical messengers released by aphid-attacked plants are described. Stimuli related to searching behaviour for high quality habitats are reviewed with special reference to the effects of botanical diversity and plant/plant communication.

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The enhancing effect of virion-free proteins derived from granulovirus (GVPs) on the infectivity of Mamestra brassicae nucleopolyhedrovirus (MabrNPV) was examined using an alternative host, Helicoverpa armigera (Hübner). Second-instar larvae were inoculated by diet contamination bioassay. The LC₅₀ values of larvae inoculated with MabrNPV alone were calculated to be 24,000 to 96,000 polyhedra/g diet, which was equivalent to the values of the original host, Mamestra brassicae (L.), in our previous report. The addition of GVPs (0.1 mg/g diet) reduced the LC₅₀ values to 1/13.8–1/38.4. Most MabrNPV-infected larvae died at the third or fourth instar, and the increase of MabrNPV concentration caused larval death at younger instars in both the MabrNPV alone treatment and the MabrNPV plus GVPs treatment. The lethal time shortened in relation to viral concentration for both the MabrNPV alone treatment and the MabrNPV plus GVPs treatment. Our results reveal the potential for simultaneous control of M. brassicae and H. armigera by adding GVPs as an enhancer to MabrNPV.

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The contents of five pheromone components and the physiological conditions of wild male and female Riptortus pedestris attracted to bait males during non-diapause (from early July to early September) and diapause (from mid-September to mid-October) periods in the field were examined. Although tetradecyl isobutyrate (14:iBu), an essential pheromone component, was detected in males attracting conspecific individuals, this component was not detected in almost all males attracted to bait males. This indicated that the attracted males are not attractive to conspecific individuals unlike bait males. During non-diapause, (E)-2-hexenyl (E)-2-hexenoate and (E)-2-hexenyl (Z)-3-hexenoate, which are synergistic components of the pheromone, were detected in most males. On the other hand, these components were not detected in most of the males during diapause, indicating that the function of these two components in the attractiveness of males might be related with the sexual communication mechanism. (E)-2-hexenyl hexanoate was detected in almost all males and females attracted to bait males. The physiological conditions were similar between adults attracted to bait males during non-diapause and diapause. Most of the attracted adults had little or no food in their stomachs. This suggested that male-attracted adults of R. pedestris are starved and are searching for suitable host plants.

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The functional responses of each instar larva and adult of the coccinellid Harmonia axyridis to adults of the green peach aphid Myzus persicae were estimated under laboratory conditions. Linear parameter estimates from a logistic model of the proportion of M. persicae consumed by H. axyridis were negative at all development stages. Although a realistic estimate for the handling time of first instar larvae could not be produced, functional response curves of fitting the data with a random predator equation exhibited a Type II curve in most development stages. Fourth instar larva had the highest attack rate and shortest prey handling time. The implications of these results are discussed with more effective stages of H. axyridis in the context of biological control.

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The red form of Tetranychus urticae Koch, the two-spotted spider mite, is known to cause damage to carnations. Previously, it was thought that the green form of the two-spotted spider mite did not damage carnations; however, in recent years, this has been rejected. Using two carnation breeding cultivars, Di-24 was damaged by the green form and Di-7 was not. The host plant acceptance, fecundity, survival rate and developmental time for the green form were investigated for each cultivar. The green form had high performance (host plant acceptance, fecundity, survival rate and developmental time) on Di-24 than on Di-7. The results of these experiments clearly show that a susceptible cultivar to the green form exists in carnations. The mechanism of host-range expansion of the green form may have involved changes to carnation cultivars.

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Four compounds, tetradecyl acetate (14:OAc), (Z)-9-tetradecenyl acetate (Z9-14:OAc), (E)-11-tetradecenyl acetate (E11-14:OAc), and (Z)-11-tetradecenyl acetate (Z11-14:OAc), have been identified in extracts of female pheromone glands of the limabean pod borer, Etiella zinckenella. A mixture of these four components successfully attracted a number of conspecific males in both Hungary and Egypt. Unfortunately, the mixture attracted only a few males, and the attractiveness was not equivalent to that of virgin females in soybean fields in Japan. We therefore analyzed the pheromone gland extract from Japanese E. zinckenella females by using gas chromatography-mass spectrometry. In addition to the four compounds previously identified, we found a dodecenyl acetate. The mass spectrum pattern and retention indices of the acetate coincided well with those of authentic (E)-9-dodecenyl acetate (E9-12:OAc). The attractiveness of the five-component mixture containing E9-12:OAc to male moths was significantly increased and equivalent to that of virgin females in field trapping tests. The numbers of males attracted did not significantly decrease when 14:OAc and E11-14:OAc were removed from the mixture, whereas almost no males were attracted when Z9-14:OAc, Z11-14:OAc, or E9-12:OAc was deleted. The results suggest that Z9-14:OAc, Z11-14:OAc, and E9-12:OAc are essential components of the sex attractant pheromone of E. zinckenella in Japan.

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Autographa nigrisigna (Lepidoptera: Noctuidae) loopers form cuticular cysts on the dorsal site of the penultimate segment by parasitization of endoparasitoid Campoletis chlorideae (Hymenoptera: Ichneumonidae) and interrupt successful parasitization by excluding the parasitoid egg and larva in the hemocoel into the cyst. This study elucidated for the first time the difference in the exclusion rates with host age at the time of parasitization. All parasitized host loopers of D1L1 (Day 1, 1st instars) and D0L2 formed cuticular cysts and nearly 70% could exclude parasitoid eggs successfully; however, the number of loopers that could form cuticular cysts decreased with host aging at the time of parasitization. To elucidate the difference between the encapsulation system and cuticular encystment, it was examined whether the substances encapsulated are excluded by cuticular encystment. A small piece of antenna the same size as an egg used as a biotic foreign substance was absolutely encapsulated and was not excluded by encystment. Further, it was clarified whether parasitoid eggs with a different surface were encapsulated or excluded by cuticular encystment with or without ovarian fluid. UV eggs (with an intact surface and development ceased by UV treatment) were hard to encapsulate, but were excluded with encystment. Plasma eggs with a degenerate surface (treated with heating for 5 min at 60°C after 10-min immersion in plasma of Pseudaletia separata) were encapsulated and not excluded by cuticular encystment, although ovarian fluid increased the cyst formation rate. These results show that cuticular encystment functions to exclude parasitoid eggs incapable of encapsulation.

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A sex pheromone component of the Japanese mealybug, Planococcus kraunhiae, was isolated and identified. A crude extract of the pheromone obtained by airborne collection was first fractionated with Florisil column chromatography. The activity of each fractionated sample was examined in Petri dishes. The active fraction was further purified by HPLC and an active component was isolated by preparative GC. The purified compound showed attraction activity to adult males of P. kraunhiae in the field. The chemical structure was determined to be 2-isopropyliden-5-methyl-4-hexen-1-yl butyrate by GC-MS and NMR analyses.

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The acute toxicity of savory (Satureja hortensis) extracts obtained with supercritical CO₂ and by traditional extraction techniques was tested on larvae of Musca domestica, Spodoptera littoralis, Culex quinquefasciatus and Leptinotarsa decemlineata and on adults of M. domestica, and the composition of volatile compounds in the extracts was determined. The efficiency of extract obtained with supercritical CO₂ at 12 MPa and 50°C was comparable with that of hydrodistillate and higher than the efficiency of other extracts, while its extraction yield was by 73% higher than the yield of hydrodistillate.

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The red imported fire ant, Solenopsis invicta, is an invasive species that has been introduced into the United States and more recently into several countries in the Asian-Pacific region. The foraging dynamics of this pest ant is important in understanding its interactions with native ant species and in devising the most effective toxic bait control methods. In this study the effect of worker density, size of the foraging area, the number of food lures, duration of experiments, and the effect of the queen on foraging activity were investigated under laboratory conditions. The results showed that of the four ant densities investigated (very small, small, medium and high) the medium ant density most consistently had more workers at the food lures than the other ant density situations. The percentage of worker ants at the food lures was negatively correlated with an increase in foraging territory size for all four worker ant densities. Significantly fewer foragers were observed in the foraging areas when a queen was present, then when the queen was absent. In addition, when number of food lures was increased from 1 to 12, the mean number of workers found at the lures was significantly higher when four food lures were present. Furthermore, the number of worker ants observed on the food lures increased for the first 2.5 h and then decreased with time. The study suggests that observations of foraging activity could be restricted to 2.5 h. These data lay the ground work for further studies in optimizing the effectiveness of fire ant bait toxicants.

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The endoparasitic mite Locustacarus buchneri Stammer has been found in commercial bumblebees (Bombus terrestris) and in Japanese native bumblebees. In an infested colony of B. terrestris reared in the laboratory, the mites moved from adult bees to 3rd or 4th instar larvae, where they waited for bees' pupation. We dissected the bee workers that emerged, and counted the numbers of eggs, mobile forms (larviform females and males), and adult females of the mite in the tracheae of the bees. Our results allowed us to roughly estimate that the developmental period from egg to mobile phase of the mites was about 2 weeks (4 weeks after bee emergence). We also revealed that the number of mites in the bee could be positively associated with the bee's age after emergence.

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We conducted mating experiments between two clades of the pea leafminer, Liriomyza huidobrensis, i.e., California Clade (CC) and South America Clade (SC). Development times from egg to pupa and egg to adult at 25°C of the two clades and the hybrid progeny were compared. In the interclade mating cross, adult hybrid progenies were obtained only from matings between CC females and SC males. The number of hybrid progeny was quite smaller than those from combinations of the same clade. Furthermore, no F2 progeny was obtained from matings between F1 hybrid progenies. CC progeny required more development times from egg to pupa and egg to adult at 25°C than SC and hybrid progeny. Our biological data indicated that the two clades of L. huidobrensis were different species, as indicated by their molecular characters in previous studies.

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Photoperiod is a major factor in the induction of pupal diapause in the ovoviviparaous flesh fly, Sarcophaga similis. This species entered diapause when kept under short-day conditions throughout the embryonic and larval stages. Exposure to long-day conditions for the whole embryonic or whole larval stage, however, prevented diapause. Moreover, most insects did not enter diapause when they were exposed to long-day conditions for only 2 days in the embryonic stage just before larviposition. When the uterus containing embryos was removed from the mother's body and kept in vitro under long-day conditions, most of these embryos became nondiapause pupae even under subsequent short-day conditions. When postfeeding larvae were exposed to long-day conditions for 3 days, 50% entered diapause. From these results, it is concluded that sensitivity to photoperiod is highest in the later embryonic stage and embryonic sensitivity to photoperiod is independent of the mother.

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The absolute population density and natural mean dispersal distance of the sugarcane click beetle Melanotus sakishimensis Ohira (Coleoptera: Elateridae) were estimated by using mark-recapture experiments in an agricultural area (180 ha) on Kurima Island, Miyakojima, Okinawa in mid-February, from 2002 to 2006. Funnel-vane traps with synthetic sex pheromone were uniformly placed along field roads at 100 points to capture adult males. Estimates of population densities of males that were obtained by the Jolly-Seber and Yamamura methods from 2002 to 2006 were 33,761, 29,727, 14,960, 11,360 and 8,634, respectively. The Yamamura method was adopted in 2004 and 2005 when the survival rates estimated by Jolly-Seber method became larger than 1. The estimate of lifetime natural mean dispersal distance (±SE) that was calculated by eliminating the influence of artificial trap removal was 193.8±11.0 m. The estimate of the male removal rate (and the 95% profile likelihood confidence interval) was 0.131 (0.117–0.147), indicating that the amount of male removal was not sufficient for the population control in this experiment.

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This study examined the microbiological features of the three reference strains of Bacillus thuringiensis whose non-insecticidal parasporal inclusions contain anticancer parasporins (PS2, PS3, and PS4). Morphometric analysis showed that the sizes and aspect ratios of the spores of these strains were in the range of those reported for the Bacillus cereus/B. thuringiensis group. The API 50CH test revealed that the carbohydrate utilization profiles of these strains were typical of the B. cereus/B. thuringiensis group. These parasporin producers proved resistant to ampicillin, and induced β-hemolysis on sheep blood agar. Overall results show that there is no significant difference in several phenotypic key characters between B. thuringiensis strains with PS2, PS3, and PS4 and those with insecticidal crystal proteins.

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In a previous study, we confirmed alterations in several fungal traits in hybrid strains of Verticillium lecanii generated via protoplast fusion. In the present study, we surveyed radial colony growth in different temperature regimes as well as conidia productivity and conidia size of hybrid strains of V. lecanii to elucidate the various primary fungal properties of these strains and to determine the correlation between these properties and virulence to insect pests. Minimum temperature thresholds for all tested strains (except Vertalec^®) were below 5°C. Optimal temperatures for colony growth were 20–25°C. Colony growth at high temperature was good or poor depending on the genotype. Temperature and strain significantly affected colony growth. Conidial production and conidia size were also significantly affected by strain. Conidial production differed by almost 170 times between the highest conidia-producing strain BbF10 and the lowest conidia-producing strain AaF30, although both strains originated from the same parents. Hybrid strains tended to show slightly larger conidia than their parent strains of the same genotype. Although all these traits varied considerably among hybrid strains, no apparent relationship of these traits with virulence to insect pests was found.

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We exposed non-diapause eggs of the rice leaf bug Trigonotylus caelestialium to a low temperature (4°C) and investigated the effects on hatching, nymphal survival, and developmental periods with a view to obtaining many newly hatched nymphs or newly emerged adults on the same day. When eggs were stored at a constant temperature of 25°C, 54.1% of nymphs and 50.9% of adults emerged on the 7th day and the 20th day after collecting them for 24 h, respectively. The hatching rates of eggs exposed to the low temperature for 7, 10, and 13 day were significantly lower than that of eggs maintained at 25°C. However, compared to the non-exposure group, only a small decrease in the hatching rate was observed in the 4-d exposure group (8.1%). Further, exposing the eggs to the low temperature did not affect the survival of the nymphs to adult emergence or the developmental periods. These results suggest that the exposure of eggs to the low temperature for 4 d or less should be a simple and useful method for obtaining many nymphs and adults on the same day.

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Mite species of the family Phytoseiidae, which includes some important natural enemies of spider mites and insect pests, found on wild plants in the vicinity of apple orchards in north Japan, were studied during 2001 to 2006. Euseius finlandicus, Typhlodromus vulgaris, and Amblyseius orientalis were recognized as the dominant species of phytoseiid mites in natural vegetation. Of 18 plant species, 5 hosted an abundant number of phytoseiid mites. Especially on Viburnum dilatatum and Morus australis, the density of phytoseiid mites on leaves was low in spring and increased gradually until autumn. When we used a “Phyto trap” as a tool to collect phytoseiid mites walking on branches, the density on V. dilatatum was high in spring and low in autumn. Phytoseiid mites in traps on M. australis had 2 peaks of occurrence, in spring and autumn. Transeius fulvus was not collected from leaves but from traps, and E. finlandicus was not collected from traps but from leaves.

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We investigated the flight speed and flight duration of Riptortus pedestris (Fabricius) (Heteroptera: Alydidae) and Leptocorisa chinensis Dallas (Heteroptera: Alydidae) to estimate their flight distance by measuring the speed of stinkbugs flying towards a window in a room with a speed sensor. R. pedestris flew faster than L. chinensis although there was no difference in speed between sexes. R. pedestris flew fastest at 29°C and slowest at 19°C; however, the flight speed of L. chinensis was not significantly different among 29, 25, and 19°C. Flight duration was measured using a flight mill for 22 hours under L13 : D11 at 25°C. The results showed that L. chinensis flew significantly longer than R. pedestris, and there was no difference between the sexes. From the product of flight speed and flight duration, the estimated R. pedestris flight distance was 3.1–4.6 km day⁻¹, and L. chinensis was 24.2–29.4 km. Flight distances calculated using only the flight mill were shorter than with a speed sensor.

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A 1.5 kb-long portion of mitochondrial DNA containing the AT-rich control region and its flanking regions was amplified by polymerase chain reaction (PCR) from 217 specimens of Bactrocera dorsalis (Hendel) collected in the Ryukyu Islands of Japan, Thailand, Vietnam, Taiwan, and Hawaii, and obtained from laboratory strains established from populations in regions where the species was formerly distributed. Analysis of restriction fragment length polymorphisms of PCR products (PCR-RFLP) using restriction enzymes DraI and SspI identified 29 different haplotypes. Of these, 27 haplotypes were detected in populations collected in Asian countries in recent years. These populations, including a population collected in the Ryukyu Islands, were similar in terms of haplotypic composition. On the other hand, the Hawaii population and laboratory strains were highly homogeneous, and contained only two and one haplotypes, respectively. Although one haplotype was common among these populations, they did not share any common haplotypes with recently collected Asian populations. Based on the results, we discussed the factors affecting genetic differences among local populations and the utility of the mitochondrial DNA fragment as a genetic marker to define the origin of insects occasionally trapped in the Ryukyu Islands.

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