Two astigmatid mites, Chaetodactylus nipponicus and Tortonia sp. are sympatrically distributed in Japan. Both species usually occur in the same host nests, but coinhabiting in the same cells was rarely found. As the second report, mechanisms 1) to determine the ratio of different hibernating stages, and 2) to inhibit coinhabiting of 2 mite species in the same host cells are studied. Field data were obtained from nests of Osmia cornifrons withdrawn from apple orchards in central and northern Japan in the winter between 2000 and 2001. Development and fecundity and other related data were obtained by rearing of mites at various temperatures in the laboratory. Life cycle of the 2 mite species consists of 3 phases, i.e., initial reproductive phase (1), multiple reproductive phase (II) and overwintering phase (III). In C. nipponicus, 2 different morphs of deutonymphs, phoretic and cyst-like, were recognized as hibernatihg stages, the former most abundant. On the other hand, in Tortonia sp. 5 hibernating stages (larva, protonymph, phoretic deutonymph, tritonymph and adult) were found. Duration from egg to adult at 28℃ in phase II was about 10 days in C. nipponicus, but it was about 15 days in Tortonia sp. Five to six generations were repeated in one pollen loaf. In C. nipponicus, 40-53 individuals of the 2 morphs of deutonymphs were produced by one mg of pollen mass. Sex ratio in adults was approximately 0.5 in both species of mites, irrespective of their ancestral stages. The total number of eggs laid per female in phase II was 234.3±48.2 (N= 12) in C. nipponicus, and 292.9±44.2 (N=15) in Tortonia sp. Fecundity was differed according to the ancestry in C. nipponicus, thus, the total number of eggs laid per female molted from the phoretic deutonymphs was 5 times that from the cyst-like duetonymphs. Intrinsic rate of natural increase (r) of C. nipponicus was much higher than that of Tortonia sp., reflecting the remarkable difference of the number of eggs laid/female/day between the mite species. Tortonia sp. was always expelled by C. nipponicus through a remarkable difference of the values of e^r (e=Napier's number) for 4 months, when they invaded the same host cells. However, in those cells whose hosts were living, the ratio of individual numbers of Tortonia sp. was higher than that of C. nipponicus, because the former can survive by feeding on host feces. In C. nipponicus, 2 morphs of deutonymphs seem to be produced, when the amount of residual pollen loaf consumed by mites reached critical volume. Those protonymphs, which ate much pollen, became phoretic deutonymphs and the less-fed became cyst-like deuto-nymphs. In Tortonia sp., those individuals which are able to feed on pollen developed into adults, but others seem to be obliged to cease their development. Protonymphs of Tortonia sp. that encountered shortage of food seem to molt as phoretic deutonymphs. The cyst-like deutonymphs in C. nipponicus and the phoretic deutonymphs in Tortonia sp. are thus regarded as hunger typed (starved) stages, respectively.

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In order to reconfirm flower visiting habits and examine the reciprocal relationship between the habits and the morphologies of scopal hairs on two Tetralonia species, T. mitsukurii and T. nipponensis (Hymenoptera: Apidae), morphological comparisons were conducted in two species by light microscope and scanning electron microscope (SEM). The material used were collected at Setaura, in Mt. Aso, Kumamoto Pref., Japan. Tetralonia nipponensis was reconfirmed to be a polyphagous and polylectic species because it visited many flower species with pollens of various species attached over the scopal hairs. All samples of T. mitsukurii had only a certain pollen species in middle to high rank of minutae (diameter: 16.5–23.0μm). The pollen grains were identified as Lespedeza bicolor from the morphological characteristics, and T. mitsukurii was considered as an oligolectic species. The scopal hairs of T. mitsukurii were shorter, thinner, closer and had more branched hairs than those of T. nipponensis. Most Japanese species in Eucerini visit various flowers with their polyphagies in the short term of spring. Tetralonia mitsukurii may have changed its period of flower visiting activities to autumn, showed intensive visits to Lespedeza and specialized scopal hairs in proportion to the small pollen grains of the flowers.

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The natural enemies of Shijimiaeoides divinus asonis were surveyed in the Aso area from 1989 to 2002. A number of predators were collected from the habitat of this butterfly: Menida violacea (Pentatomidae); Promachus yesomicus (Asilidae); Agelena limbata (Oxyopidae); Tibellus oblongus (Philodromidae); Xysticus ephippitatus (Thomisidae) and Carthus xanthogramma (Salticidae). M. violacea was observed to prey on the larvae of S. divinus asonis. In addition, Cordyceps sp. (Clavicipitaceae), an entomopathogenic fungus of this butterfly, and Trichogramma sp. (Trichogrammatidae), the egg parasitoid, were collected. Of these indigenous natural enemies, T. sp. is likely to be the most effective against this butterfly. The effect of pasturage on abundance of S. divinus asonis was also investigated. The percentage parasitism of T. sp. was high in the area where routine pasturage was not carried out. Routine pasturage seems to have positive influence on the population of this butterfly. We conclude that the pasturage in these areas shall be necessary in order to preserve the population of S. divinus asonis as well as to maintain the grassland.

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We observed that a fungivorous moth, Diomea cremata damaged the shiitake mushroom, Lentinula edodes (Berk.) Pegler cultivated on synthetic logs (mainly composed of sawdust), which have replaced the use of natural logs over the last decade. It is considered that D. cremata has become a new pest of this fungus. The larvae appear to consume the thick brown mycelial coat formed on the surface of synthetic logs rather than the fresh fruit body.

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Chrysolina virgata (Motschulsky) was listed as "Data Deficient" in the Red Data Book of Japan (Japan Environmental Agency, 2000). In this paper, the geographical distribution in Japan was shown based on the field investigations and the literature records.

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