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Secondary contact between incipient species and selection against maladaptive hybridization can drive reinforcement between populations in contact and result in reproductive character displacement (RCD). Resultant divergence in mating traits within a species may generate downstream reproductive isolation between populations with displaced and non-displaced traits, referred to as the cascade reinforcement hypothesis. We examined this hypothesis using three allopatric populations of the ground beetle Carabus maiyasanus with a genital lock-and-key system. This species shows RCD in male and female genital morphologies in populations in contact with the sister species C. iwawakianus. In a reciprocal mating experiment using three allopatric populations with differences in male and female genital sizes, insemination failure increased as the difference in genital size increased. Based on the reproductive isolation index, insemination failure was the major postmating-prezygotic isolation barrier, at least in one population pair with comparable total isolation to those of other species pairs. By contrast, there was only incomplete premating isolation among populations. These results suggest that RCD in genital morphologies drives incipient allopatric speciation, supporting the cascade reinforcement hypothesis. These findings provide insight into the roles of interspecific interactions and subsequent trait diversification in speciation processes.

Genital morphology reveals rapid diversification among species, and species-specific divergence in genital morphology may result in reproductive isolation and promote speciation. Natural selection against maladaptive hybridization may cause species-specific genital divergence. In this context, divergence in mating traits is expected to be greater between sympatric populations than between allopatric populations in a pair of species, known as reproductive character displacement (RCD). However, there are few examples of RCD in the genital morphology of closely related species. Additionally, processes leading to RCD have rarely been inferred. In this study, we examined RCD and its underlying mechanisms by focusing on species-specific genital morphologies of closely related Ohomopterus ground beetle species. A morphological analysis showed patterns of RCD in species-specific genital parts in both sexes. Interspecific hybridization was confirmed by a mate choice experiment and by a population genetic analysis indicating extensive interspecific gene flow, suggesting that reinforcement is the most plausible process underlying the observed RCD. We found variation in the degree of displacement in contact zones, which may correspond with the ongoing process of genital evolution and speciation. Our results provide support for the lock-and-key hypothesis of genital evolution in closely related Ohomopterus species.

SummaryAlong with many long-distance migrant passerine species in the East Asian-Australasian Flyway, the migratory Brown Shrike Lanius cristatus superciliosus has been sharply declining throughout its breeding range. Its breeding range in Japan shrank by 90.9% between the 1910s and 2010s. In contrast, the closely related but resident Bull-headed Shrike L. bucephalus bucephalus has been gradually declining but is still a common resident in Japan. To better understand the drastic decline of Brown Shrike, we compared the pairing success during three consecutive breeding seasons of these two species. About 60–70% of Brown Shrike males were unpaired, which was much higher than the percentage of unpaired male Bull-headed Shrike (c.0–20%). Brown Shrike males arriving later did not pair because the population’s sex proportion is heavily biased toward males. One of the factors of male-biased population of Brown Shrike may be female-biased mortality in wintering sites, or on the migratory journey, and tracking studies will be required to test this.

Intraspecific variation provides insight into heterogeneous demography and adaptive history across distribution ranges of organisms. Most species distribution models assume that species respond to the environment as a single undifferentiated entity across their entire distribution. However, populations occupying different niches might differ in their ability to cope with climate change. Here, we assessed potential climatic niche differentiation at the species and subspecies levels and identified the palaeoclimatic range of three cold-adapted, low-dispersal beetle species: Carabus irregularis, Platycerus albisomni and Platycerus takakuwai. Our results showed that: (1) MaxEnt models incorporating information derived from intraspecific variation outperformed the species-level models; (2) tests of niche similarity revealed niche conservatism in most subspecies, except for two subspecies of C. irregularis, C. i. irregularis and C. i. bucephalus; and (3) historical predictions suggested substantial shifts within species ranges, with multiple glacial refugia during the Last Glacial Maximum. In conclusion, we recommend closer examination of intraspecific variation when predicting species distributions, in order to obtain more accurate generalizations regarding range shifts under climate change.

The effects of climate change on species distribution are typically inferred based on species distribution models (SDMs) that do not account for the dispersal ability of species. Here we investigated the utility of dispersal ability measures in predicting the distribution of 10 Platycerus species in Japan, which are cold‐adapted stag beetles sharing ecological and morphological features. We generated three SDMs based on environmental variables without dispersal constraint and incorporating two alternative dispersal constraint scenarios. We compared these three models with respect to SDM performance and the predicted degree of range overlap between neighbouring species. Using the best models among three SDMs, we predicted range shifts under climate change. Additionally, we characterised environmental differences among species distributional areas. Our results revealed that models incorporating dispersal constraints had better predictive performance. Platycerus delicatulus occupied a largest suitable habitat and P. sue had a narrow range in Japan. Most of Platycerus taxa in 2070 were predicted to lose large portions of present suitable areas. Moreover, environment was confirmed to affect the distribution of the targeted species. Incorporating dispersal ability to better understand the effects of climate change on the species ranges is a crucial step towards developing policies for insect management and conservation of vulnerable species.

This study estimates the degree of the transmission of income shocks to consumption using the partial insurance model of Blundell et al. (2008) and data taken from the Japanese Panel Survey of Consumers that cover the recessions in the 2000s. The analysis finds that the transmission of permanent income shocks to consumption was insured by half, whereas transitory income shocks were almost fully insured. Meanwhile, permanent income shocks statistically did not change over this period, whereas transitory income shocks did. These results suggest that the partial insurance model does not contradict observational changes in consumption and income inequality.

Genital morphology reveals rapid diversification among species, and species-specific divergence in genital morphology may result in reproductive isolation and promote speciation. Natural selection against maladaptive hybridization may cause species-specific genital divergence. In this context, divergence in mating traits is expected to be greater between sympatric populations than between allopatric populations in a pair of species, known as reproductive character displacement (RCD). However, there are few examples of RCD in the genital morphology of closely related species. Additionally, processes leading to RCD have rarely been inferred. In this study, we examined RCD and its underlying mechanisms by focusing on species-specific genital morphologies of closely related

We developed a lipid nanoparticle formulation (LNPK15) to deliver siRNA to a tumor for target gene knock down. LNPK15 is highly PEGylated with 3.3% 1,2-distearoyl-sn-glycero-3-phosphatidylethanolamine-N-(polyethylene glycol-2000) (PEG-DSPE) and shows a long duration: the half-lives of siRNA in LNPK15 were 15.2 and 27.0h in mice and monkeys, respectively. Although LNPK15 encapsulating KRAS-targeting siRNA (LNPK15/KRAS) had very weak KRAS gene knock down activity in MIA PaCa-2 cells in vitro, LNPK15/KRAS showed a strong anti-tumor efficacy in MIA PaCa-2 tumor xenograft mice after intravenous administration at 5mg/kg twice weekly. KRAS mRNA and protein knock down was observed in tumor tissue, suggesting on-target anti-tumor efficacy. In order to elucidate the in vitro-in vivo discrepancy, we performed ex vivo knock down assay using serum samples obtained after intravenous administration of LNPK15/KRAS to mice and monkeys. The collected samples were added to MIA PaCa-2 cells, and KRAS gene knock down was evaluated after a 24-h incubation period. The knock down efficacy was weak (≈20%) with serum samples at initial sampling point (2h), and it became much stronger (∼90%) with serum samples at later time points. Lipid composition of LNPK15 in the serum samples was also investigated. Among the five lipids incorporated in LNPK15, PEG-DSPE was degraded more rapidly than siRNA and the other lipids in both mice and monkeys. In vitro lipase treatment of LNPK15/KRAS also hydrolyzed PEG-DSPE and enhanced knock down activity. From these results, it was concluded that LNPK15 acquires increased knock down activity after undergoing PEG-DSPE hydrolysis in vivo, and that is the key mechanism to achieve both long circulation and potent knock down efficiency. We also proposed an in vitro assay system using lipase for quality control of LNP to ensure biological activity.

Simple Summary Neolucanus swinhoei is a widespread species of stag beetle distributed across the subtropical Taiwan Island. The biological features of weak flying capability, two-week adult lifespan, and strong dependence on forests are the key factors determining its genetic differentiation. We investigated the influence of historical climatic oscillations in Pleistocene on the distribution of N. swinhoei. The complex population genetic structure and dispersal routes of eastern populations are affected by the geographic isolation of the north/south-oriented Central Mountain Range (CMR) during periodical Pleistocene glaciations. Four possible shelters were inferred for the distribution of N. swinhoei in each geographic region during the periodical glaciations. The coexistence of widely distributed ancestral haplotypes and the locally derived ones are deduced to be the possible explanation of long-distance dispersal events for N. swinhoei. In the presence of the CMR, the northern and southern low mountains are proposed as alternative routes for N. swinhoei. The present study proposes dispersal routes from eastern to western Taiwan, in contrast to the more common scenarios of western-to-eastern dispersal found in other studies. Abstract The present study demonstrates that the complicated genetic structure of the hilly lineage of the Neolucanus swinhoei complex was driven by its biological features and habitat requirements as well as hindrance by the CMR during periodical Pleistocene glaciations. The results revealed a tendency of geographical differentiation and major and sub- lineage divergences before and after the Riss glaciation, followed by stable population growth during Würm glaciation. At least four refugia were inferred for N. swinhoei during the Riss–Würm glaciations. The ancestral haplotype retention in the cytochrome oxidase subunit I (COI) gene and compensated substitution in 16S rRNA gene is a possible evolutionary scenario resulting in the inconsistent evolution pattern between COI and 16S rRNA gene coupled with the long-distance dispersal of N. swinhoei. Although the CMR did hinder the dispersal of N. swinhoei, its ancestors may have dispersed to eastern Taiwan through the northern and southern low mountains of the CMR before the Riss glaciation. Our finding suggests that the population growth in the Würm glaciation led a dispersal back to western Taiwan, which is contrast to the more common dispersal scenario from western Taiwan to eastern populations proposed in other studies.

Adult females of stag beetles (Coleoptera: Lucanidae) possess an ovipositor-associated mycangium for conveying symbiotic microorganisms. In most lucanid species, their mycangium contains yeast symbionts of the genus Scheffersomyces Kurtzman & M. Suzuki, 2010 that are known for their xylose-fermenting capability. The lucanid genus Platycerus Geoffroy, 1762 is a group of small blue stag beetles, in which ten Japanese species constitute a monophyletic clade. Here we examined the evolutionary relationships of these Japanese Platycerus species and their yeast symbionts, together with a Korean Platycerus species and other lucanid species as outgroup taxa. Based on the internal transcribed spacer (ITS) and the intergenic spacer (IGS) sequences, the yeast symbionts of all Platycerus species were closely related to each other and formed a monophyletic clade. There is no variation in ITS sequences of the yeast symbionts of the Japanese Platycerus species. Based on IGS sequences, the yeast symbionts formed clusters that largely reflected the geographic distribution of the host insects, being shared by sympatric Platycerus species except for P. delicatulus Lewis, 1883 and P. viridicuprus Kubota, Kubota & Otobe, 2008. The symbiont phylogeny was globally not congruent with the host COI-based phylogeny, although some local congruences were observed. Statistically significant correlations were detected between the genetic distances of COI sequences of the host insects and those of IGS sequences of the yeast symbionts in Japan. These results suggest that, at least to some extent, the host insects and the yeast symbionts may have experienced co-evolutionary associations. While the Japanese Platycerus species formed a monophyletic clade in the COI phylogeny, the yeast symbionts of Japanese P. viridicuprus were very closely related to those of Korean P. hongwonpyoi Imura & Choe, 1989, suggesting the possibility that a recent secondary contact of the two beetle species during a marine withdrawal, e.g., in the last glacial period, might have resulted in an inter-specific horizontal transmission of the yeast symbiont.

Large size and low dislocation density bulk gallium nitride (GaN) crystals were successfully grown by original acidic ammonothermal method SCAAT™ (Super Critical Acidic Ammonia Technology). It enabled us to obtain extremely high crystallinity true bulk GaN. In this article, 2-inch size non-polar m-plane GaN and nearly 4-inch size polar c-plane GaN were demonstrated. The dislocation and stacking fault density of m-plane GaN were in the range of 102 to 103 cm-2 and 0 to 5 cm-1, respectively. The full width at half maximum (FWHM) of X-ray rocking curve (XRC) on (10-12) plane was 6.4 arcsec. The dislocation density of c-plane GaN was in the range of 103 to 104 cm-2. The off-angle distribution of nearly 4-inch size c-plane GaN was ±0.006° in the span of 80 mm. The types of dislocations in the c-plane GaN were identified by transmission electron microscope (TEM) observation. Hydride vapor phase epitaxy (HVPE) growth on the SCAA™ c-plane seed was carried out and obtained 2-inch wafer. The crystallinity was comparable to SCAAT™ seed; FWHM of XRC was less than 10 arcsec and off-angle distribution was ±0.017°.

This paper examines the long-term consequences of elementary school curricula on the formation of social preferences. The estimation results, using Japanese data, show that the hidden (non-academic) curriculum at public elementary schools varies widely by region and is associated with preference formation. Specifically, people who have experienced participatory and cooperative learning practices are more likely to be altruistic, cooperative with others, reciprocal, and have national pride. In contrast, education emphasizing anti-competitive practices is negatively associated with these attributes. Such contrasts can also be seen in other preferences regarding government policies and the market economy. The findings imply that elementary school education, as a place for early socialization, plays an important role in the formation of life-long social preferences.

Among insect-fungus relationships, xylose-fermenting Scheffersomyces yeasts are well known for their potential in utilizing wood hemicelluloses and their association with various wood-feeding insects. However, their specificity to host insects or strain-level diversity within host species has not been clearly elucidated. In the insect family Lucanidae, larvae usually feed on decaying wood, and adult females consistently possess a fungus-storage organ, called the mycangium, near the abdominal tip. Here the authors investigated host-symbiont relationships between Scheffersomyces yeast symbionts and small blue stag beetles of the genus Platycerus (Coleoptera: Lucanidae) in East Asia by using intergenic spacer (IGS) region as a genetic marker. All yeast strains isolated from the female mycangium of three Platycerus species, P. hongwonpyoi from Korea and P. acuticollis and P. delicatulus from Japan, were allied to Scheffersomyces segobiensis based on the sequences of the nrDNA 26S and internal transcribed spacer (ITS), in which no sequence difference was observed among those strains. However, IGS regions showed clear genetic differentiation within the yeast symbionts of P. hongwonpyoi, as well as between those of Korean and Japanese Platycerus species. In the IGS sequences, nucleotide substitutions were mainly distributed in the whole stretch of IGS1 and the anterior half of IGS2, whereas nucleotide gaps were localized at IGS1 and the middle of IGS2. Despite the conserved association between the Platycerus beetles and the specific strains of S. segobiensis in East Asia, geophylogenetic divergence patterns of the yeast symbionts were not concordant with those of the insect hosts.

To investigate the history of differentiation of the Pterostichus raptor species group of carabid beetles, endemic to the Korean Peninsula and adjacent islands, we performed cladistic analyses based on 30 adult morphological characters for all 12 species of the group and an outgroup species. The resultant tree revealed three monophyletic clades within the group, each of which is composed of 3–6 parapatric or allopatric species; the three clades occur sympatrically in most parts of the peninsula. Reconstructions of geographic range history on the obtained tree showed that the initial divergence of the three clades occurred in the Taebaek Mountains and that each clade subsequently dispersed southward and speciated after that dispersal.

This paper estimates the effects of childhood experiences of wearing school uniforms at public elementary schools in Japan on individual preferences in relation to others (hereafter, other-regarding preferences) in adulthood. The school uniform experience can be endogenous if the preferences and characteristics of the school and parents are included in the decision of schools to implement school uniforms. To examine the causal effect of school uniforms, we exploit the exogenous variation in the expansion of the apparel industry across regions, which the Japanese government used as a catalyst in stimulating the economy, as well as the regional variations in prefectural governors’ initiatives for enhancing regional profitability. We find that that the experience of school uniforms increases reciprocal inclinations and inequity aversion (prosocial) tendencies. We discuss the reasons behind the consequences of school uniform policies on students’ other-regarding preferences later in life, with a focus on an individual’s perception of similarity with others shaped during childhood.

This study investigates the effects of the 2002 Japanese reforms of compulsory education on household expenditure on supplementary schooling and out-of-school activities for junior high school students. These reforms marked a dramatic change in Japan's compulsory education system in two main respects: from April 2002, every Saturday became a public school holiday and instructional time was reduced following the government's revisions of national curriculum guidelines, leaving private schools largely unaffected. Based on aggregate data taken from the Child Study Expenditure Survey, the difference-in-differences estimation—households with children attending public schools as the treatment group and those attending private schools as the control group—reveals that the 2002 educational reforms increased target household expenditure on supplementary education by 13% and spending on outdoor activities/volunteering, arts, sports, and cultural activities by 23%. Disaggregated analysis based on microdata taken from the National Survey of Family Income and Expenditure carried out by the Bureau of Statistics further reveals that the impacts of these educational reforms were larger for higher-income households than for lower-income ones.

Ecological character displacement predicts that interspecific resource competition results in greater trait divergence between species in sympatry than in allopatry. However, other processes, such as ecological sorting, result in the same pattern of trait variation. In this study, we characterize character displacement in eight species of snail-feeding Acoptolabrus ground beetles in the Far East. Acoptolabrus exhibit divergent feeding phenotypes, including species with a slender forebody that is able to intrude into large shells and species with stout heads and mandibles for crushing small shells. The pattern of character displacement in feeding phenotypes was confirmed by multivariate analysis of body dimensions. Molecular phylogenetic analysis, divergence time estimation and biogeographical analysis revealed that sympatry and phenotypic divergence occurred repeatedly during the Pleistocene and almost simultaneously within each geographical area. Comparative analysis revealed that the evolution of feeding phenotypes best fitted a selective model with three adaptive optima, corresponding to the three cases of sympatry with a congener. Repeated coincidences of sympatry and adaptive differentiation in feeding phenotypes suggested causal relationships, although the precise order of events was difficult to discriminate. This study provides insight into the spatiotemporal dynamics of interspecific interactions and adaptive phenotypic diversification.

We examined the genetic divergence of Platycerus hongwonpyoi Imura & Choe, 1989 in South Korea using the nuclear wingless (Wg) gene, internal transcribed spacer (ITS) region and mitochondrial cytochrome oxidase subunit I (COI) gene. We found no variation in Wg or ITS. Based on COI, P. hongwonpyoi was split into four well defined and one weakly supported clades, which were inferred to have diverged 2.11–1.33 Ma. The Platycerus hongwonpyoi population size seems to have decreased during the past several tens of thousands of years. The divergence times of major clades of P. hongwonpyoi were comparable with those involved in the speciation of certain Japanese species. Frequent overlapping of different clades at the same sites suggests the occurrence of secondary gene flow following differentiation in South Korea. In conclusion, the genus Platycerus underwent strikingly different divergence patterns in South Korea compared with Japan according to the disparate topographies of these two geographical areas.

Wood degradation by insects plays important roles for the forest matter cycling. Since wood is deficient in nitrogen compared to the insect body, wood-feeding insects need to assimilate the nitrogen selectively and discard an excess carbon. Such a stoichiometric imbalance between food and body will cause high metabolic cost; therefore, wood-feeding insects may somehow alleviate the stoichiometric imbalance. Here, we investigated the carbon and nitrogen budgets of the larvae of stag beetle, Dorcus rectus, which feed on decaying wood. Assimilation efficiency of ingested wood was 22%, and those values based on the carbon and nitrogen were 27 and 45%, respectively, suggesting the selective digestion of nitrogen in wood. Element-based gross growth efficiency was much higher for nitrogen (45%) than for carbon (3%). As a result, the larvae released 24% of the ingested carbon as volatile, whereas almost no gaseous exchange was observed for nitrogen. Moreover, solubility-based elementary analysis revealed that the larvae mainly utilized alkaline-soluble-water-insoluble fraction of wood, which is rich in nitrogen. Actually, the midgut of the larvae was highly alkaline (pH 10.3). Stag beetle larvae are known to exhibit coprophagy, and here we also confirmed that alkaline-soluble-water-insoluble nitrogen increased again from fresh feces to old feces in the field. Stable isotope analysis suggested the utilization of aerial nitrogen by larvae; however, its actual contribution is still disputable. Those results suggest that D. rectus larvae selectively utilize alkaline-soluble nitrogenous substrates by using their highly alkaline midgut, and perhaps associate with microbes that enhance the nitrogen recycling in feces.

We have fabricated diluted magnetic semiconductors (DMSs) based on organic–inorganic layered perovskite-type compounds, in which multiple quantum well structures were formed. DMSs were synthesized ...

Globally, c. 0.8–1.2 million species of insects exist, with Coleoptera making up about 40% of this total. Pitfall traps for collecting ground beetles were installed at 11 study plots in Baekdudaegan mountain of Gangwon-do. Individual trapped species were counted and analyzed at each study area. This study has been carried out to provide basic data for analyzing forest health and investigating the competitive distribution among biological species in the forest environment through a field investigation on the species composition, diversity, and dominance rate of Coleoptera. Carabidae were collected using pitfall traps at the study area in Backdudaegan Mountain of Gangwon-do, and the individual number of collected species was counted. Collected ground beetles in the study area comprised 837 individuals, 14 genus, and 32 species. In this study, 217, 303, 144, and 209 individuals were found in Jinburyung, Mt. Odaesan, Mt. Taebaeksan, and Mt. Dutasan area, respectively. The abundance of ground beetles was relat...

Kohei Kubota,1,2 Kohei Onishi,3 Kazuaki Sawaki,3 Tianshu Li,4 Kaoru Mitsuoka,5 Takaaki Sato,6 Shinji Takeoka1,3,4 1Cooperative Major in Advanced Biomedical Sciences, Graduate School of Advanced Sciences and Engineering, Waseda University (TWIns), Tokyo, Japan; 2Formulation Research and Phramaceutical Process Group, CMC R&D Center, Kyowa Hakko Kirin Co., Ltd, Shizuoka, Japan; 3Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering,Waseda University (TWIns), Tokyo, Japan; 4Research Organization for Nano and Life Innovation, Waseda University (TWIns), Tokyo, Japan; 5Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, Osaka, Japan; 6Department of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University, Nagano, Japan Abstract: Two lipid-based nanoformulations have been used to date in clinical studies: lipoplexes and lipid nanoparticles (LNPs). In this study, we prepared small interfering RNA (siRNA)-loaded carriers using lipid components of the same composition to form molecular assemblies of differing structures, and evaluated the impact of structure on cellular uptake and immune stimulation. Lipoplexes are electrostatic complexes formed by mixing preformed cationic lipid liposomes with anionic siRNA in an aqueous environment, whereas LNPs are nanoparticles embedding siRNA prepared by mixing an alcoholic lipid solution with an aqueous siRNA solution in one step. Although the physicochemical properties of lipoplexes and LNPs were similar except for small increases in apparent size of lipoplexes and zeta potential of LNPs, siRNA uptake efficiency of LNPs was significantly higher than that of lipoplexes. Furthermore, in the case of LNPs, both siRNA and lipid were effectively incorporated into cells in a co-assembled state; however, in the case of lipoplexes, the amount of siRNA internalized into cells was small in comparison with lipid. siRNAs in lipoplexes were thought to be more likely to localize on the particle surface and thereby undergo dissociation into the medium. Inflammatory cytokine responses also appeared to differ between lipoplexes and LNPs. For tumor necrosis factor-α, release was mainly caused by siRNA. On the other hand, the release of interleukin-1β was mainly due to the cationic nature of particles. LNPs released lower amounts of tumor necrosis factor-α and interleukin-1β than lipoplexes and were thus considered to be better tolerated with respect to cytokine release. Inconclusion, siRNA-loaded nanoformulations effect their cellular uptake and immune stimulation in a manner that depends on the structure of the molecular assembly; therefore, nanoformulations should be optimized before extending studies into the in vivo environment. Keywords: nanoformulation, siRNA, cryo-TEM, confocal microscopy, endocytosis, immune stimulation

This study estimates the intergenerational wealth elasticity using original Japanese survey data and assesses factors explaining the intergenerational wealth elasticity, such as income, educational level, bequests and preferences. The age-adjusted elasticity of child wealth with respect to parental wealth ranges from 0.266 to 0.367, and transition matrices indicate that the intergenerational transmission of wealth persists more strongly in the tails of the distributions. The correlation between parent and child wealth mainly stems from income, education and bequests, which jointly constitute 63.9% of the wealth elasticity.

Japanese Abstract: 本研究は，一般的信頼，互恵性，利他性などのソーシャル・キャピタルが，所得・従業上の地位・管理職という労働市場でのアウトカムと幸福度に与える影響を個人に関する独自のアンケート調査をもとに検証した．ソーシャル・キャピタルの内生性に対処するために，小学生の頃に通学路および自宅の近隣に寺院・地蔵・神社があったか否かという変数を用いた．分析結果は操作変数法の有効性を示しており，推計結果からはソーシャル・キャピタルが高くても労働市場でのアウトカムには影響しないが，幸福度および健康水準を高めることが示唆された．また，労働市場でのアウトカムを高めない理由として，ソーシャル・キャピタルが高いと地域間移動が減少するという事実を示した． English Abstract: This study examines the effects of social capital, such as general trust, reciprocity, and altruism, on labor market outcomes, such as income, occupational status, and promotion, and health and happiness by conducting a survey among individuals. To cope with the endogeneity of social capital, we used indicator variables to map temples, Jizo bodhisattvas, and shrines on the individuals’ school route or near their home during elementary school days. The results show that instrumental variables work well and that social capital does not affect labor market outcomes but increases happiness and health levels.

A Satoyama landscape is an important reservoir of biodiversity; however, in post-industrial era traditional Satoyama management became economically unfeasible. To maintain Satoyama, labor-saving management styles have begun to be implemented. In contrast to the traditional styles based on labor-intensive practices such as rotational tree clear-cutting, the labor-saving styles consist mainly in tree thinning and ground vegetation cutting within a small spatial range. The consequences of this new approach are unclear, and our study aimed at filling this gap in our knowledge by analyzing the effects of small scale management on ground beetle community in suburban Satoyama (Kashiwa city, central Japan). We applied labor-saving management at limited spatial range, and sampled and analyzed ground beetles both before and after management. Cluster analysis revealed three groups of beetle assemblages, corresponding to three habitats: forest, bamboo stand and grassland. Comparison of wing traits showed that, before management, brachypterous beetles dominated forest plots and macropterous beetles were more prominent in the grassland plot, while in the bamboo stand both types of wing morphology were evenly represented. This trend can be linked to habitat structural stability driven by vegetation regeneration cycles which reflect dominant plant longevity. After management, macroptery increased in all three habitats. Probably, habitat disturbance created by vegetation management gave advantage to macropterous beetles over brachypterous beetles. These results suggest that wing type can be linked to vegetation structural stability. In some species, decline in abundance was accompanied with decline in body size. Our study shows that small scale Satoyama management can have pronounced effects on beetle assemblages.

Using original web survey data, this study investigates the long-term consequences of the experience of group work, which is a common teaching practice. We examined the convention in the context of Japanese public elementary schools, which are considered to be less susceptible to self-selection bias, in order to improve on the research conditions of previous studies. The regression results show that the experience of group work is negatively associated with annual income and financial assets. Furthermore, we find that the experience of group work does not relate to well-being and whole life satisfaction and that those who experienced group work attach higher satisfaction to human relationships and less satisfaction to household economic status. From the insignificant association between group work and well-being/whole life satisfaction, it may be interpreted that the positive association with satisfaction related to human relationships offsets the negative association with satisfaction regarding one’s present economic status. We also show that experience of group work is negatively associated with cognitive skills but is positively associated with altruistic and positive reciprocal behavior.

Larvae of the stag beetle, Dorcus rectus, feed on decaying wood, which they digest with the aid of symbiotic yeasts; however, they can be successfully reared on artificial diets containing only fungal tissue. In this study we tested whether D. rectus larvae can utilize fungal cell walls, which are an insoluble component of mycelium. Lyophilized Bjerkandera adusta mycelium cultured in potato-dextrose liquid medium consisted of a 47.6% hot-water insoluble fraction by mass, which contains 53.7% of the total nitrogen in the mycelium. D. rectus larvae that hatched from surface-sterilized eggs were reared for 14 days on agar-based diets containing either the soluble fraction, insoluble fraction or both, extracted from 100 mg of mycelium. The larvae increased in mass most on the mixed diet, and there was no difference in their growth on the mixed and positive control diets. Both the soluble and insoluble fractions improved larval growth compared to the negative control diet; however, the growth rates were much lower than those expected from the nitrogen dose-growth response curve obtained in a previous study. Addition of b-chitin to the soluble fraction did not positively affect larval growth. Therefore, we conclude that (1) D. rectus larvae need both the soluble and insoluble fractions of mycelium and (2) the larvae digest the insoluble fraction using their own enzymes.

Plasma electrolytic oxidation (PEO) on a die-casting ACM522 Mg alloy was conducted in aqueous silicate and phosphate solutions. The corrosion behavior of the anodized ACM522 Mg alloy was investigated in detail. During the investigation, the self-repairing behavior of the anodized films was evaluated by a salt spray test for 168 h, and the mechanism of this self-repairing was discussed in terms of thermodynamic equilibrium constants. Furthermore, the effects of additives to the phosphate solution on the self-repairing behavior were examined, and the addition of Na 2 B 4 O 7 was found to effectively reduce cracks on a self-repaired film.

The mechanical isolation hypothesis predicts that physical incompatibility between divergent reproductive morphologies hinders hybridization between populations. However, evidence for this hypothesis remains scarce. We examined this hypothesis using two parapatric carabid beetles, Carabus insulicola and C. esakii, which are of the subgenus Ohomopterus and exhibit a species-specific genital lock-and-key system. Our interspecific crossing experiment revealed that incompatibility of genital morphologies served as a strong postmating-prezygotic isolation barrier. This isolation was asymmetric: a decrease in female fitness was more costly in the cross with greater genitalic incompatibility between a C.esakii female and a C. insulicola male. These two species share a limited sympatric area, but the mechanism responsible for their coexistence is unclear given no evidence of premating isolation via male mate choice. A comparison of the present results with those of previous studies that quantified reproductive isolation between Ohomopterus species suggest that strong mechanical isolation via genitalic incompatibility plays a major role in species isolation, but that it may be less important in species coexistence.

Plasma electrolytic oxidation (PEO) on a newly designed ACM522 magnesium die-casting alloy has been conducted in an aqueous phosphate solution and the morphology and corrosion resistance of the PEO films were investigated in detail. By covering the whole surface of the substrate with the PEO film, the corrosion resistance was significantly improved; the modified surface endured a salt spray test for 168 h. It was also clarified that traces of local breakdown caused by excessive PEO can be a cause of pitting corrosion, resulting in significant decline in corrosion resistance with PEO time.

Molecular phylogenies of the genus Platycerus in Japan were characterized based on the nuclear 28S ribosomal RNA and mitochondrial cytochrome oxidase subunit I (COI) genes. These analyses, combined with our previous morphological information, revealed a detailed diversification process of Platycerus in Japan, as well as estimates of their divergence times. Japanese species were monophyletic and were inferred to have diverged to the acuticollis species group and all other species ca 1.69 Mya. The acuticollis species group then appeared to split into P. viridicuprus and a group including P. takakuwai, P. albisomni and P. acuticollis ca 1.26 Mya. Other specific divergences have occurred primarily since ca 0.33 Mya. Comparing the molecular trees and the morphological tree, we also found introgression of the COI gene in some species. Genetic divergence of Platycerus has occurred intensely in southwestern Japan.

Species assembly in ground beetle (Coleoptera: Carabidae) communities in local microhabitats was studied in a forest. The following questions were addressed: are there important filters that sort the species in the assemblages? If so, what is the specific nature of these filters? In order to address these questions rarefaction analysis was used to determine whether ground beetle species are distributed non-randomly. Next, the nature of filters was determined by analyzing (1) the community matrix and searching for the consequences of competitive exclusion and (2) species-environmental relations. Rarefaction analysis revealed that the species composition is filtered: species richness was less than expected and there were fewer than expected congeneric species coexisting at high beetle population densities. However, community matrix and body size analyses did not detect significant competition among the beetle species and the matrix was significantly nested. Species-environmental analyses indicated that the ground beetle assembly was strongly linked to ground vegetation. It is concluded that spatial distribution of ground beetles across local communities in this forest habitat is determined more by local environmental conditions than competition, and ground beetles do not interact strongly among themselves so that competitive effects do not play an important role in their distribution except at high beetle population densities.

The male endophallic morphology and mitochondrial cytochrome oxidase subunit I (COI) gene of two parapatric species of the acuticollis species group, Platycerus acuticollis and P. albisomni, were examined at the border between the two species. No morphologically inferred hybrid was found. The endophallic and mitochondrial types of each individual were significantly linked, and the two species inferred by both types were essentially parapatric even at a very local level. We inferred that the reproductive isolation between them is high, although introgressive hybridization occurred rarely. The taxonomical assignment of P. acuticollis and P. albisomni as two distinct species is considered appropriate.

The molecular phylogeny of the long-horned beetle tribe Lamiini Mulsant (Coleoptera: Cerambycidae) in Japan (12 genera, 25 species, 3 additional subspecies) was determined based on mitochondrial 16S rRNA and cytochrome oxydase subunit I. The monophyly of the tribe Lamiini was supported, whereas that of the genus Acalolepta Pascoe was unclear. Evolution of host plant use in Lamiini was estimated using the molecular phylogeny. For adult and larval host plant kind-and-condition, the most ancestral state was for weakened to dead broad-leaved trees, whereas derived states favored conifers, healthy broad-leaved trees, and herbs. For adult and larval host range, the most ancestral state was polyphagy, whereas oligophagy and monophagy were derived. Evolution of hosts' idiosyncrasy and that of the insects' host range were related in many lineages. Our results partly support the hypothesis that habitation in living trees requires dietary specialization in phytophagous insects.

Most wood-feeding insects need an association with microbes to utilize wood as food, and some have special organs to store and convey the microbes. We report here the discovery of the microbe-storage organ (mycangium) in stag beetles (Coleoptera: Lucanidae), which develop in decayed wood. The mycangium, which was discovered in the abdomen, is present in all adult females of 22 lucanid species examined in this study, but absent in adult males. By contrast, adult insects of both sexes of selected Passalidae, Geotrupidae, and Scarabaeidae, which are related to Lucanidae, lacked mycangia similar to those of the lucanid species. Yeast-like microbes were isolated from the mycangium of five lucanid species. DNA sequence analyses indicate that the microbes are closely related to the xylose-fermenting yeasts Pichia stipitis, Pichia segobiensis, or Pichia sp. known from the gut of a passalid species.

1. Species diversities of some insect lineages have been attributed to differentiation of feeding habits among species. Our objective was to determine variation in diet composition among harpaline ground beetle species occurring in a riverside grassland. 2. We examined the diet compositions of 14 species from six genera in the spring and 10 species from two genera in the autumn. We performed measurements of nitrogen and carbon stable isotope ratios in consumers and in their potential food items, and estimated relative contributions of different food items with two mixing models, IsoSource and MixSIR. 3. IsoSource and MixSIR software gave similar results, but IsoSource tended to calculate higher contributions of principal food items and smaller percentile ranges than MixSIR. Among harparine beetle species, there were diverse food utilisation patterns among four food categories (detritivorous invertebrates, herbivorous invertebrates, C3 plants, and C4 plants). Detritivores comprised the main diets of abundant harpaline species in the spring, whereas abundant harpaline species in the autumn were primarily herbivores feeding on C4 plants, or omnivores feeding on herbivorous invertebrates and C3 plants. Seasonal changes in food use were related to seasonal changes in the abundance of each food resource. 4. Mixing model analysis of stable isotope ratios is a convenient and effective method for roughly estimating diets of many species with diverse food habits (such as ground beetles). This method can contribute to determining the trophic relationships of related insects in one ecosystem.

To reveal differences in phylogeographic patterns of flightless insect species occurring in different regions of Japan, we studied the phylogeography and demographic history of Silpha beetles occurring in cool-temperate habitats of two major islands, Honshu and Hokkaido, using sequences of the mitochondrial cytochrome oxidase subunit I (COI) gene. Honshu has a more mountainous topography, and cool-temperate habitats occur discontinuously, whereas Hokkaido, located to the north of Honshu, has more continuous cool-temperate habitats. A species endemic to Honshu, S. longicornis occurs on Honshu, whereas S. perforata occurs on Hokkaido and the East Asian continent. Our results indicate that the ancestors of S. longicornis colonized Honshu via a south-west route c. 0.7 Mya and the species has highly divergent populations in isolated mountainous areas of Honshu, whereas S. perforata colonized Hokkaido via a northern route less than 90 000 years ago and has less divergent geographic populations. During the last glacial period, S. perforata was probably restricted to refugia in southern Hokkaido and later expanded into northern Hokkaido, whereas S. longicornis populations existed in many isolated refugia, probably because of the complex topography of Honshu. Thus, our study demonstrates that, even between closely related species, interactions among biology, latitudinal climatic gradients and topography can produce different phylogeographic patterns. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 452–467.

We constructed a phylogeny of the ground beetle subgenus Nialoe (s. lat.), genus Pterostichus (Coleoptera: Carabidae) based on two mitochondrial (cytochrome oxidase I and 16S ribosomal DNA) and one nuclear (28S ribosomal DNA) gene sequences. Thirty-three representative species of the group and three outgroup species were analyzed. The resultant trees (maximum parsimonious, maximum likelihood and Bayesian trees of the combined data of the three gene sequences) indicated that there are two large and three small lineages in the group, some of which were supported by a previous morphology-based phylogeny. In all the analyses, the small lineage composed of two Korean species is sister to the rest of the subgenus, but relationships of other four lineages differed among the analyses and remained unresolved. The implications of the present results are discussed in terms of taxonomy and biogeography of the group.