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Curculio sikkimensis (Heller) (Coleoptera: Curculionidae) is a serious pest of the Japanese chestnut, Castanea crenata, because the larvae feed inside seeds. Chestnut seeds are usually harvested before the larvae leave them, meaning it is unlikely that the weevil is based in orchards. Instead, adults from neighboring woodlands likely invade orchards to oviposit. In this study, I examined host plant use and the course of development of Cu. sikkimensis in mixed oak and chestnut coppice stands to improve our understanding of weevil infestations in chestnut orchards. Females oviposited into seeds of three Quercus species and Ca. crenata, whose seed maturation times differed, over several months. The phenology of the weevil’s oviposition most closely tracked that of Quercus serrata seed maturation. Mature larvae left the seeds and burrowed into the soil, where they overwintered—in some cases for up to three winters because of prolonged diapause. Adults emerged over the course of 1 month and survived for about 2 months; such traits seem to enable this weevil to reproduce for several months. Thus, Cu. sikkimensis uses several host plants in coppice stands, and its oviposition phenology suggests that it is more dependent on Q. serrata than on Ca. crenata.

Many researchers have studied the relationship between masting by trees and seed predation by insects. Most of these studies have been plant centered, with little focus on the insect perspective. To estimate the effect of mast seeding on insect seed predators, the life-history traits of these insects must also be considered because some seed insects can survive lean years by prolonged diapause. In this study, I examined larval infestation of acorns and life-history traits of the acorn weevil, Curculio robustus (Roelofs) (Coleoptera: Curculionidae), in relation to acorn production of the deciduous oak Quercus acutissima Carruthers (Fagaceae) in a coppice stand in central Japan in 2004–2009. Curculio robustus females oviposit into Q. acutissima acorns, inside which the larvae develop. Mature larvae leave acorns and burrow into the soil, where they overwinter. Although germination did occur in acorns infested by weevil larvae, the percentage of germination was lower in acorns damaged by many larvae. Acorn production in Q. acutissima varied considerably among years. Both the number of C. robustus larvae infesting acorns and the percentage of acorns infested were affected by the amount of acorns produced by Q. acutissima, and two successive lean years appeared to have a considerable impact on C. robustus population size. Consequently, only a small fraction of the acorns produced were lost to predation in a mast year after two successive lean years. However, C. robustus could survive the two successive lean years because of prolonged larval diapause, probably leading to a marked decrease in population size. These findings suggest that masting in Q. acutissima succeeds as a predator satiation strategy in response to acorn damage by C. robustus, and that C. robustus has developed prolonged diapause as a counter-adaptation.

The chestnut weevil Curculio sikkimensis undergoes a prolonged larval diapause that is completed by repeated exposure to chilling and warming. We examined the possible reversibility of diapause intensity in response to temperature changes. All larvae were subjected to an initial chilling followed by incubation at 20°C to force pupation of the 1-year-type larvae that require only one winter for diapause completion. We then exposed the larvae remaining in prolonged diapause to a second chilling at 5°C for different lengths of time, preceded or not preceded by incubation at 20°C (moderately high) and/or 25°C (high) and followed by a final post-chilling reincubation at 20°C. Many of the prolonged-diapausing larvae subjected only to a brief second chilling were re-activated upon reincubation. However, short exposure to 25°C before this second chilling dramatically decreased the percentage of larvae completing diapause. When larvae were exposed to 25°C for a short period, then incubated at 20°C and subjected to the brief second chilling, many were re-activated during reincubation. The chilling time required for most of the larvae to complete diapause decreased after pre-chilling incubation at 20°C and increased after incubation at 25°C. These results demonstrate that diapause intensity in C. sikkimensis changes reversibly in response to changes in ambient temperature.

We studied the attraction of a tachinid fly, Gymnosoma rotundatum (Linnaeus) to the male-produced aggregation pheromone of the brown-winged green bug, Plautia stali Scott, its parasitism on the bug, and its seasonal occurrence in the field. The tachinid fly was continuously attracted to the aggregation pheromone from spring to autumn and utilized the bugs as hosts. Our field experiment to clarify the effect of the pheromone on parasitism demonstrated that parasitism occurred only in female bugs baited with synthetic aggregation pheromone and did not occur in females without the pheromone. The parasitoid flies therefore appeared to use the bug’s pheromone as a host-finding kairomone. The pheromone attracted not only female flies but also males. Male flies may increase their chance of encountering pheromone-attracted females by waiting near pheromone sources. The tachinid develops multiple generations in active hosts from spring to autumn and overwinters in dormant hosts. Thus, G. rotundatum seems to be highly adapted to using P. stali as its host, and it is a potentially important biological control agent of P. stali populations in the field.

Beauveria bassiana strain HF338 had the highest pathogenicity among 77 isolates to larvae of the chestnut weevil, Curculio sikkimensis (Heller) (Coleoptera: Curculionidae). Its pathogenicity at 25°C was similar to that of Metarhizium anisopliae strain HF293. Its pathogenicity at 15°C remained high, whereas that of M. anisopliae HF293 was greatly reduced. Its pathogenicity to chestnut weevil adults and nut fruit moth, Cydia kurokoi (Amsel) (Lepidoptera: Tortricidae), was also higher than those of M. anisopliae HF293. In field tests, the survival rate of chestnut weevil larvae decreased to 2.9% when B. bassiana HF338 was applied at 1×1011 conidia/pot. The high pathogenicity of B. bassiana HF338 makes the strain a potential microbial agent for the control of chestnut pests.

Curculio sikkimensis (Coleoptera: Curculionidae) requires one or more years to complete its life cycle, owing to prolonged larval diapause. To compare the effects of temperature cycles and total periods of chilling on the termination of prolonged diapause, larvae were subjected to different chilling (5 degrees C) and warming (20 degrees C) cycles ranging from 30 to 720 days, and all cycles were repeated until the sum of chilling and warming periods reached 720 days. The prolonged diapause of C. sikkimensis was more effectively terminated by repeated cycles of chilling and warming than by prolonging the continuous chilling period. However, extremely short temperature cycles were not highly effective in enhancing diapause termination, even when such cycles were repeated many times. To examine the role of warming periods on diapause termination, diapause larvae were subjected to a sequence of chilling (120 days at 5 degrees C) and warming (240 days at 20 degrees C) with a warming period (0-120 days at 20 degrees C) inserted in the chilling period. Diapause larvae that were not reactivated in the first chilling period required exposure to a certain period of warming before they were able to complete diapause development in the subsequent chilling. Thus, C. sikkimensis appears to spread its reactivation times over several years in response to seasonal temperature cycles.

In Eobiana engelhardti subtropica, early laid eggs reach the diapause stage in early autumn. For long periods before winter, the eggs are exposed to temperatures higher than their theoretical lower threshold for development. In contrast, late-laid eggs cannot reach their diapause stage before winter. Our study showed that E. e. subtropica copes with these difficulties via the thermal response involving embryonic diapause. In this katydid, the almost fully developed embryo undergoes an obligatory diapause. When diapause eggs were maintained at a temperature of 20 degrees C or higher, diapause persisted for a long time. Diapause was effectively terminated by temperatures ranging from 1 to 11 degrees C, and hatching occurred successfully at temperatures from 11 to 15 degrees C. In addition to the chilling temperature, pre-chilling temperature modified diapause intensity and hatching time. Diapause eggs hatched earlier after chilling when the pre-chilling temperature was lower, within a range of 14.5-25 degrees C. Thus, the low-temperature requirement for diapause termination prevents early laid eggs from untimely hatching in autumn, and low temperatures before and during winter decrease diapause intensity and shorten the hatching time in the following spring. When eggs were chilled before diapause, they tolerated chilling and averted diapause. Thus, even if eggs encounter low temperatures before diapause, they can hatch in the following spring.

The developmental biology of a tachinid parasitoid (Gymnosoma rotundatum) and the effects of its parasitism on reproduction of the host, the brown-winged green bug (Plautia crossota stali), were studied. The tachinid females laid eggs on the abdominal tergum of the hosts and larvae penetrated into and developed in their body cavities. A single mature larva exited from each of the hosts and pupariated. Even in cases when the fly deposited two eggs onto a host, only one maggot survived to maturity. The hosts died within a day after the maggot emerged. The percentage of larvae emerging from hosts, larval duration, and puparial weight were not affected by the number (one or two) of parasitoid eggs per host. The duration of the larval stage was longer and puparia were bigger in parasitoids that emerged from female hosts than those that emerged from male hosts; G. rotundatum was so variable in body size that larger individuals tended to emerge from larger hosts. Though parasitoids did develop even in unfed hosts, such puparia were much smaller in size than puparia developed in fed hosts. The reproductive abilities of the parasitized bugs gradually reduced as the tachinid maggots matured. In parasitized female bugs, ovaries gradually shrank with a suppression of oviposition. Both the number of laid eggs and the percentage of viable eggs decreased rapidly after the 8th day of parasitization. In parasitized male bugs, the fertility rates decreased rapidly after the 8th day of parasitization.

Eobiana engelhardti subtropica (formerly Metrioptera hime) is wing-dimorphic. The long-winged (LW) morph was clearly induced by crowding during the nymphal stages. Short-winged (SW) females produced eggs more intensively in an earlier period than did LW females. This difference in egg production between the two wing morphs seems to be associated with different patterns of increase in body weight after adult emergence. The body weight of SW females rapidly increased and reached its peak at about the time when oviposition started. On the other hand, the increase in body weight of LW females was slow, although it continued even after the start of oviposition. These findings suggest that the SW morph is adapted to sedentary life and rapid reproduction and that the LW morph tends to migrate before or during reproduction. However, in both the morphs, reproductive traits (pre-oviposition period, egg-laying period, number of eggs laid, and longevity) were to some extent flexible and could be modified by photoperiodic conditions.

Embryonic development in relation to life cycle adaptation was studied in the northern (Aomori, 40.6°N) and southern (Osaka, 34.9°N) strains of Eobiana engelhardti subtropica (formerly Metrioptera hime) (Orthoptera: Tettigoniidae). Eggs of the 2 strains showed similar thermal responses. At 20, 22.5, and 25°C, they developed to the mature embryonic stage without delay and entered an obligatory embryonic diapause (final diapause). At 27.5 and 30°C, on the other hand, embryonic development was markedly delayed. This retardation was more striking in the southern strain. Especially, summer diapause occurred in half-grown embryos at 30°C. A shift of temperature from 30°C to 20 or 25°C terminated summer diapause and the eggs started to develop. The final diapause is never terminated if kept at high temperatures. Final diapause requires an exposure to a cold temperature of 15°C or lower and the intensity is higher in the southern strain. Adults of the southern strain emerged in mid June or earlier and those of the northern in early-mid July. In outdoor experiments, the developmental rate decreased more conspicuously in the eggs laid earlier in the southern population. As a result, the eggs reached the final-diapause stage in autumn more synchronously than expected from the long egg-laying period. The decreased developmental rate and summer diapause appear to secure survival in the hot season and ensure reaching the embryonic diapause stage synchronously in autumn. The local variation in the final-diapause intensity seems to be related to the heat units in autumn which might otherwise cause untimely hatching.

合成アパタイトの粉末をフッ素およびランタンの二段処理 (F-La 処理) すると, 表面に非晶質フッ化ランタン (LaF3) ができ, 酸に対する溶解度が著しく減少することを見出し, これまでにこの方法の臨床応用への可能性を検討してきた。今回は, 前報で得られた最適条件で処理した抜去ヒト永久歯につき, まず前回より過酷な酸溶解試験 (pH4.0, 24時間) および人工う蝕試験をおこない, エナメル質からのカルシウム溶出量ならびに歯質の脱灰状態を調べた。次に, F-La処理表面のブラッシングによる耐摩耗性を検討した。その結果, 以下のことがわかった。(1) 酸溶解試験24時間後において, F-La処理永久歯からのカルシウム総溶出量は, 酸性フッ素リン酸溶液処理 (F処理) 単独の場合に比べ約1/2に減少した。また, マイクロラジオグラフィーより, F-La処理永久歯の脱灰された表面には, 高石灰化層が観察された。(2) 人工う蝕試験 (平均pH4.5, 9時間) において, F-La処理永久歯では, 歯質の脱灰がF処理の約3/5に抑制されていた。(3) 10,000回のブラッシング摩耗後の試料の切断表面につき, X線マイクロアナライザーを用いて, 各元素の分布を分析した結果, 約5μmの層が削り取られたが, 摩耗表面から約10μmの深さまでランタンおよびフッ素元素の存在が認められた。(4) (3) で得られた摩耗試験後の試料につき, 1時間の酸溶解試験を行ったところ, それら元素は表面から約5μmの深さまで残存することが認められ, 酸および摩耗作用から歯質が保護されていることがわかった。

A series of four antibodies against rat osteoblasts have been produced using the hybridoma technique. After bone cells isolated from newborn rat calvariae by a sequential digestion procedure were cultured for 3 days, the cells were trypsinized and further maintained in rotation cultures overnight. Out of the cultured bone cells alkaline phosphatase-positive cells were sorted by flow cytometry and used as immunogens. The clones secreting the antibodies were selected on the basis of the abilities of these antibodies to bind to the bone cells but not to fibroblasts from neonatal rat head skins, in an enzyme-linked immunosorbent assay. Clones of two hybridomas, designated AOB-1 and AOB-2, were used to characterize the antigenic determinant(s) in osteogenic cells. The antibody showed the reactivity with isolated alkaline phosphatase-positive cells, osteogenic tissue cells in newborn rat calvaria, and mandibula, but not with the cells in head skin, lung, kidney, liver, or stomach as determined by immunofluorescence study. Western blot analysis has identified the antigenic determinants possessing apparent molecular weights of 210,000, 110,000, 65,000, 58,000, 40,000, 36,000, 32,000, 28,000, 25,000, 17,000, and 15,000 of osteoblast-rich monolayer cultured cells. According to the cell surface detection with biotin-avidin protein blotting technique, these fractions appear to be present as components of the cell surface of the osteoblast.

Though fluorescent X-ray spectrometers have been applied for analysis of trace elements in many fields, few studies were reported on the odontological use of this method.In order to obtain a simple and quick analytical method for trace elements in deciduous teeth, pH of sample solution, APDC amount to be added, andaging time for precipitation were mainly examined.A deciduous tooth was dissolved by H NO3 and a metal complex was formed in which APDC bonded with trace elements in the tooth solution. Then, trace element analysis was carried out by a fluorescent X-ray spectrometer after the precipitation was collected on the Millipore filter.As a result, trace elements such as Cu, Zn, Pb, and Fe in primary teeth were determined quantitatively and it was elucidated that data were obtained without interference when excesses in the amounts of Ca and PO4 existing in teeth were removed, because the APDC did not form any precipitation with Ca2+and P8+.

A quantitative analysis of the mandibular bone trabeculae of 44 patients with Down's syndrome and 68 normal persons by means of panoramic tomography was performed with a laser scan system. The results showed that the normal persons exhibited a correlation between the trabecular pattern and aging, whereas the patients with Down's syndrome showed no such correlation. These findings were consistent with geromorphism, which is one of the systemic features of Down's syndrome.

A one-year clinical study was carried out on 181 school children 6 to 11 years old to compare the caries-preventive effect of three commonly used topical fluoride agents: an acid phosphate-fluoride solution (2% NaF, 0.15MH3PO4, pH 3.6), an 8 percent aqueous stannous fluoride solution, and a 2 percent aqueous sodium fluoride solution.Four groups -including the control group- were formed, each group representing as nearly as possible an equal cross section of the entire body of subjects.The most careful procedure of topical application with a tray was used; applications were performed once yearly except in one group. This group was received topical application of a 2 percent aqueous sodium fluoride solution four times in two weeks according to the method of Knutson.Considerable protection was afforded by all three of these agents, and especially by the acid phosphate-fluoride solution.