Eye-color mutants were found in the flower bugs, Orius sauteri (Poppius) and O. strigicollis (Poppius), which are effective natural enemies of thrips and mites. The mutants have bright red eyes, and are easily discriminated from the wild type (with purple to black eyes) after the 2nd nymphal instar. By crossing experiments, it was determined that the red eye trait was recessive and the locus was inferred to be autosomal in both species. In experiments using the mutants, it was shown that Orius sauteri and O. strigicollis females mate only once or a few times during their lifetimes. Similar mutants may be found in other Orius populations or species.

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The effects of feeding and starvation during the 4th larval stadium on the later development of Dacne picta (Coleoptera: Erotylidae) were observed by rearing under various diet regimens on dried fruiting bodies of shiitake mushroom, Lentinula edodes. When the food was removed after different durations of feeding, pupation occurred at ca. 7 d after removal of the food resource irrespective of the duration of the feeding period. The body size of eclosed adults increased with longer feeding periods. We investigated the feeding response of larvae provided mushrooms as food after different durations of initial feeding and starvation periods. Two responses were observed. Larvae either resumed feeding on the mushrooms (re-feeding individuals) or did not resume feeding (non re-feeding individuals), and these patterns resulted in large and small adult size, respectively. Re-feeding during the larval stage only influenced the body size of individuals which had had short initial feeding and starvation periods, and the percentage of re-feeding individuals also decreased with the protraction of the initial feeding and starvation periods. Adult body size of non re-feeding individuals decreased with protraction of the starvation period between feedings. This indicates that the pupation of larvae depends on larval mass and duration of the starvation period. The threshold larval size of males at metamorphosis was significantly smaller than that of females. This pattern of larval growth and pupation of the beetles would be advantageous when completing immature development on a short-lasting food resource. Further, such size dependent pupation of larvae would result in larger size of females than males, and synchronization of pupation and eclosion.

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The reproductive isolation between two host races of Aspidiotus cryptomeriae was examined by comparing intra- and inter-racial responses of males to live virgin females and to sex pheromones in the laboratory. No inter-racial copulation of males to live females was observed for either sex combination. These results indicated that ethological isolation was present between the races. We showed by using a crude extracts test that both host races have female sex pheromones. Although an inter-racial response of males to female extracts was observed, it was much weaker than the intra-racial responses, suggesting that the sex pheromone system plays an important role in reproductive isolation between the two races. These results support the hypothesis that each host race is a distinct species.

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In field tests conducted in Chinese yam fields in Tottori Prefecture of Japan in 1998, maximum catches of Acrolepiopsis nagaimo males were obtained at ratios between 50 : 50 and 75 : 25 (=natural ratio) when 100 μg of a binary blend of (Z)-11-hexadecenyl acetate (Z11-16:Ac) and (Z)-11-hexadecenal (Z11-16:Ald) was baited in the traps. This attractiveness was apparently enhanced when 1% to 5% of (Z)-11-hexadecen-1-ol (Z11-16:OH) was added. When 2% Z11-16:OH was blended, the synergistic effect was apparent at high doses (≥100 μg/septum). The third compound, Z11-16:OH, was therefore confirmed as a sex pheromone component. The optimum blend for male attraction was determined to be 200–1000 μg/septum of a 50 : 50 : 2 blend of Z11-16:Ac, Z11-16:Ald and Z11-16:OH, respectively. More than ten times as many males were captured with this blend than with two 2- to 3-d-old virgin females.

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Parastrachia japonensis (Heteroptera: Cydnidae) is a subsocial shield bug: females guard eggs and nymphs against predators, and provision their nymph-containing nests with drupes of the single host tree, Schoepfia jasminodora. We observed the occurrence pattern of nymphs in a foraging area under natural field conditions as an indication of nymphal stadium at independence, and experimentally compared the degree of predation risk of independent nymphs among four of the five nymphal stadia. A field monitoring census indicated that most nymphs became independent during the 4th stadium in 1998. Field experiments using carabid beetles as predators, however, indicated that predation risk during the 2nd to 4th stadia was equally high, and that of the 5th stadium was significantly lower.

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Factitious hosts are needed for mass-propagation in crop pest management. Egg parasitoids are considered as effective biocontrol agents of lepidopterous pests because they kill host eggs and can usually be easily mass propagated on factitious hosts. However, previous studies indicated that parasitoids which had been reared on a factitious host changed host preference and did not parasitize the native host. In the present report, Trichogramma dendrolimi were collected from egg masses of Mamestra brassicae in cabbage fields maintained without insecticides. T. dendrolimi was maintained in the laboratory for 12 successive generations on Ephestia kuehniella. After the 12 successive generations, the parasitoid females still preferred M. brassicae to E. kuehniella for oviposition. T. dendrolimi, that emerged from M. brassicae eggs were larger in size and laid twice as many eggs as those from E. kuehniella during their lifetime. These results suggest that T. dendrolimi parasitizes the native host without losing host preference even after 12 successive generations on a factitious host.

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The effect of food supply on longevity and fecundity of the adult cigarette beetle, Lasioderma serricorne F., was tested under the dark conditions of 30°C and 70% RH. When both males and females were provided with either pollen or water, their mean longevities were almost the same as those of control males and females without a supply of food. On the other hand, if males and females were supplied with both pollen and water simultaneously, their mean longevities were extended about twice as long as those of controls. Both mean oviposition period and mean number of eggs deposited also increased. Females that started feeding on pollen and water before the 7th day after emergence laid nearly equal number of eggs as females feeding throughout their life. When females started feeding on the 9th day, their fecundity increased and oviposition period was prolonged. When mated females were supplied with food together with an oviposition site from just after emergence, their maximum longevity was about 50 d. On the other hand, mated females supplied food without an oviposition site showed a maximum longevity of 80 d. These results suggest that cigarette beetles emigrate from a dry food factory and storage to the field, and feed in the field.

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Nine partial sequences characteristic of cytochrome P450 (CYP) were obtained by RT-PCR using degenerate primers designed from conserved regions of the CYP6 family. The sequences were CYP6A1, CYP6D1 and seven new CYPs. Full amino acid sequences of CYP6D1 and two new CYP isoforms, CYP6A24 and CYP6D3v2 were analyzed. The amino acid sequence of CYP6D1 in the pyrethroid resistant strains was identical with that of a susceptible strain, CS, already reported. Northern blot analysis indicated that CYP6D1, CYP6A24 and CYP6D3v2 were overexpressed in all pyrethroid resistant strains when compared with the susceptible strain. In conclusion, pyrethroid resistant strains in Japan show simultaneous overexpression of several CYP isoforms.

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Anomala cuprea larvae were inoculated with Metarhizium anisopliae after topical application of synthetic insecticides, and the blood cells in the larval bodies were counted. There were fewer granular cells in A. cuprea after a mixed application of M. anisopliae and fenitrothion or teflubenzuron than after a single application of M. anisopliae. The phenoloxidase activity of larval hemolymph declined with time after the treatment of M. anisopliae and insecticides. One of the mechanisms of this synergistic effect is attributed to be weakening of the immune system of A. cuprea larvae by insecticidal stress, which facilitates infection of M. anisopliae to larvae.

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Ceranisus menes is an effective parasitoid of Thrips palmi. To determine whether C. menes reared on Frankliniella intonsa can develop and reproduce on T. palmi, we studied the effects of these two host species on development and reproduction of a thelytokous strain of this parasitoid in the laboratory. There was no significant difference in total developmental time of the parasitoid between the two host species. C. menes reared on F. intonsa were larger than those reared on T. palmi. The reproduction of C. menes was examined for three host treatments: (1) the parasitoid reared on F. intonsa was allowed to oviposit in F. intonsa (F. intonsa to F. intonsa), (2) F. intonsa to T. palmi and (3) T. palmi to T. palmi. Adult longevity and total fecundity of C. menes did not differ significantly among those treatments. This thelytokous strain of C. menes had a higher reproductive rate than both host species. We conclude that the mass-reared thelytokous C. menes strain using F. intonsa may be a viable option in controlling T. palmi.

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Observations were made on the attraction and aggregation behaviour of two predatory nematodes Mesodorylaimus bastiani (Dorylaimida: Dorylaimidae), and Aquatides thornei (Dorylaimida: Nygolaimidae) at feeding sites using saprophagous and plant parasitic nematodes as prey. Parameters viz., time taken by predators to form the feeding sites, number of the feeding sites, duration of feeding, duration of post-feeding aggregation, duration for which the feeding sites existed, number of predators present, number of predators feeding upon a prey, number of predators showing during-feeding and post-feeding aggregation at the feeding sites were selected for the present study. Six to ten individuals of predators were present per feeding site but the number of feeding predators was always more than those showing during-feeding aggregation at the site. Feeding sites, which were formed earlier showed prolonged post-feeding aggregation of predators. Different values for the rate of site formation, number of sites formed, and aggregation activities during and after feeding at the feeding sites of the two predators reflected differential predatory potentials.

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Three species of tetranychoid mites living on imported plants were recently intercepted at the plant quarantine of Narita Airport. They were identified as follows: Oligonychus obliquus sp. nov., off squash from Mexico; Tetranychus malaysiensis Ehara, off okra from Thailand; Tenuipalpus caudatus (Dugès), off Viburnum from Italy. A description of O. obliquus sp. nov. and redescriptions of the other species are given. T. malaysiensis is recorded from Thailand for the first time.

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