The biosynthetic pathway of neral and its key enzyme(s) in Carpoglyphus lactis were elucidated using a crude enzyme solution obtained from C. lactis. Geraniol, which was biosynthesized via the mevalonate pathway, was first oxidized to geranial, and then geranial was isomerized to neral in C. lactis. Geraniol's geometrical isomer, nerol, was not converted by the crude enzyme solution. The body of C. lactis contained geraniol dehydrogenase (GeDH) dependent on NAD⁺ and a factor that catalyzes the isomerization of geranial to neral. Four GeDHs were found in the crude enzyme solution of C. lactis when subjected to electrophoresis followed by staining with nitro blue tetrazolium and phenazine methosulfate in the presence of geraniol as a substrate. This is the first report of GeDHs from an animal.

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Two new species belonging to the genus Trhypochthoniellus were described from several mires in northern Japan: T. brevisetus sp. nov. and T. taisetsuensis sp. nov. The Japanese species, described as T. setosus Willmann, 1928 in the past (Kuriki and Aoki, 1989) should be regarded as T. brevisetus sp. nov. according to Weigmann's conception (1997 and 1999) and Subias (2004) by 1) large body size, 2) three pairs of setae (le, in and ex) on prodorsum longer than any other congeneric species, 3) short setae (c₁, c₂, cp, d₁ and d₂) on notogaster, 4) setae h₃ remote from h₂, 5) seta cha on chelicera minute, approximating to seta chb, and 6) lacking of solenidion ω₂ on tarsus II. The species showed some morphological variations between the specimen in low altitude localities and high altitude localities. T. taisetsuensis sp. nov. is distinguishable from any congeneric species by 1) small body size, 2) notogastral surface lacking network-like structure, 3) the small number of genital setae, and 4) long setae on infracapiturum.

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Mites of the genus Neoseiulus are predatory mites that feed on pest species such as the two-spotted spider mite (Tetranychus urticae) and therefore act as biocontrol agents. Since the 1990s, the population of N. californicus in central and southwestern Japan has increased sharply, replacing the native N. womersleyi in many orchards in this area. However, in orchards of northern Japan, N. californicus is much less abundant than N. womersleyi. Here we tested the hypothesis that the lower abundance of N. californicus in the north is due to a lack of cold hardiness. The mean supercooling points of adult females of two strains of N. californicus (an indigenous strain and a commercial strain, neither of which enters diapause) and diapause and non-diapause N. womersleyi were all in the range −21.9 – 23.3°C and were not significantly different. However, more than 50% of diapause females of N. womersleyi survived for more than 7 days exposed to −5°C, while most females of the non-diapause N. womersleyi and the two N. californicus strains died after 3–5 days of exposure to −5°C. Exposure of adult females to −5°C for various periods did not significantly affect subsequent fecundity and egg viability. These results suggest that the lower cold hardiness of N. californicus might be one of the factors halting its northern advance, but it is probably not sufficient to be the only factor.

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We examined structures of acarinaria and phoretic mite faunas of the large carpenter bees Xylocopa amamensis, X. flavifrons, X. albinotum, and X. ogasawarensis from Japan, and compared them with those of X. tranquebarorum and X. ruficeps from Taiwan. While the first three Japanese Xylocopa bees had acarinaria both on the mesosoma and on the first metasomal tergum like the common Japanese large carpenter bee, X. appendiculata circumvolans, X. ogasawarensis did not have distinctive mesosomal acarinaria. Xylocopa tranquebarorum, which nests in bamboo, did not have either kind of acarinarium. Of the species examined, only X. ruficeps had a distinctive metasomal acarinarium, which was a deep, round cavity that opened on the first metasomal tergum. All mites except for Dinogamasus were collected from host's mesosoma, wing base furrows, mesosomal acarinaria and the metasomal acarinarium. We collected mites of two Sennertia spp. (alfkeni, japonica) and Horstia helenae from the Japanese bees. The Taiwanese bees also carried Sennertia and Horstia mites but probably of different species. Only X. ruficeps carried mesostigmatid mites (Dinogamasus sp.) in the metasomal acarinarium. We suggest that Sennertia deutonymphs are well adapted to be phoretic on the large carpenter bees with specialized body structures such as attachment organs and hook-like pretarsal claws as seen in other astigmatids phoretic on bees. In contrast, putatively beneficial mites, such as those of the genus Dinogamasus, have possibly been specialized to settle in the distinctive acarinaria in the course of mutualistic evolution with the host.

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The lethal effects of two types of oxygen absorbers on the house dust mites, Dermatophagoides farinae, D. pteronyssinus and Tyrophagus putrescentiae were studied. The mortality obtained after 48 hours in an air-tight container with iron (Fe)-type oxygen absorbers was 100% for D. farinae, and D. pteronyssinus, but was not 100% for T. putrescentiae. On the other hand, the mortality obtained after 72 hours in an air-tight container with ascorbic-acid-type oxygen absorbers was not 100% for either Dermatophagoides species, suggesting that their tolerance to oxygen deprivation increased in the presence of carbon dioxide derived from the ascorbic-acid-type of oxygen absorber.

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