Population dynamics of the green leafhopper,Nephotettix virescens Distant (Hemiptera: Cicadellidae) in synchronized and staggered transplanting areas of paddy fileds in Indonesia

Summary The population dynamics ofNephotettix virescens, a vector of rice tungro virus disease was investigated in a synchronized transplanting area at Jatisari (1984–1986), West Java and in a staggered transplanting area at Sidan (1986–1988), Bali, Indonesia. The FARMCOP suction sampler was employed for population censuses ofN. virescens and its natural enemies. The population growth pattern was affected by transplanting pattern: In the staggered transplanting area, the population density increased from the immigrant generation to the first generation, and sharply decrease thereafter, while in the synchronized transplanting area the population density often reached the highest peak in the second generation. The degree of contageousness in the spatial distribution ofN. virescens was negatively correlated with population density of the immigrant generation. Contribution from Indonesia-Japan Joint Program on Food Crop Protection     

Those Who are Left Behind: An Estimate of the Number of Family Members of Suicide Victims in Japan

This paper contributes to the literature of suicide studies by presenting procedures and its estimates of the number of family members who lose their loved ones to suicide. Using Japanese aggregate level data, three main findings emerge: first, there are approximately five bereaved family members per suicide; second, in 2006, there were about 90,000 children who had lost a parent to suicide; and third, in 2006, there were about three million living family members who had lost a loved one to suicide. The direct production loss of bereaved family members in 2006 alone is estimated at approximately 197 million USD. These results are valuable in evaluating the cost-effectiveness of suicide prevention programs and in designing appropriate policy instruments.     

Development of the Movements Impressions Emotions Model: Evaluation of Movements and Impressions Related to the Perception of Emotions in Dance

The purpose of this study is to specify the characteristics that contribute to the perception of emotions expressed through dance movements and to develop an emotional model to show the relationships between impressions and the characteristics of expressive body movements. Six dancers expressed three different emotions through dance: joy, sadness, and anger. Observers (N = 192) rated both their impressions (33 dimensions) and the dance movements (26 characteristics) of 18 dance performances. The results showed that the observers could accurately perceive the emotional meanings expressed in the dances. The impressions of Dynamics, Expansion, and Stability—and the evaluated movements of Frequency and Velocity of Upward Extension, Frequency and Velocity of Downward Movements, Turning or Jumping, and Body Closing—were extracted via factor analysis as determinants of observers’ impressions of emotional expressions in dance. Additionally, covariance structure analysis and discriminant function analysis indicated that the emotional expressions of the dances expressing joy, sadness, and anger are each associated with particular factors. Through these analyses, we developed the Movements Impressions Emotions Model for dance.     

Comparative analysis of population characteristics of the brown planthopper,Nilaparvata lugens st?l, between wet and dry rice cropping seasons in West Java, Indonesia

Summary Population dynamics of the brown planthopper (BPH),Nilaparvata lugens St?l, were investigated in paddy fields in the coastal lowland of West Java, Indonesia, where rice is cultivated twice a year, in the wet and dry cropping seasons. Distinct differences in the basic features of population dynamics were detected between the two rice cropping seasons: (1) In the wet season, BPH populations multiplied rapidly in the period from initial to peak generation, reaching quite often the destructive level despite the low density of initial immigrants. However, in the dry season, the population growth rate and the peak population density were much lower than those in the wet season. The abundance of natural enemies such as arthropod predators played a major role in determining such a difference in seasonal population development. (2) The density at the peak generation or the occurrence of outbreaks in each field was predictable in the wet season with fairly high accuracy on the basis of the density at the initial or previous seasonal generations. In the dry season, however, the rate of population growth and the peak population density widely varied among the fields depending on the water status in each field. (3) Density-dependent processes to regulate the population density were detected in both cropping seasons. In the wet season, the regulatory processes were only detected in such high densities as cause the considerable deterioration of host plants, which suggested that the processes were largely attributable to intra-specific competition. In the dry season, however, the regulatory processes operated at a much lower density in the earlier stages of the crops. The results of an analysis of adult longevity or residence period suggested that the density-dependent dispersal of macropterous adults played an important role in stabilizing the population fluctuation among the fields in the early dry season.     

Demographic attributes of an introduced herbivorous lady beetle

Demographic attributes of the adults of an introduced herbivorous lady beetleEpilachna niponica (Coleoptera: Coccinellidae) were investigated from 1975 to 1981 in the Botanical Garden of Kyoto University. Population growth rate varied from 4.8 to 16.8 throughout the study period. Fecundity and mortality in the late larval period contributed most to annual changes in the population growth rate. Population growth rate was negatively correlated with the density of overwintering adults. Adult survival from emergence to the reproductive season, which varied from 0.03 to 0.36 throughout the study, was almost completely determined by survival during the pre-hibernation period. Adult survival to the preproductive season changed in a size- and sex-dependent manner. Larger adults survived better than smaller individuals; male-biased mortality occurred from adult emergence to the reproductive age. Severe intraspecific competition among late instar larvae due to host plant defoliation produced a higher proportion of small-sized adults, resulting in lower adult survival to hibernation. The introduced population had a higher population growth rate and a lower adult survival to the reproductive season than the source population.     

Quantitative Risk Assessment of Vibrio parahaemolyticus in Finfish: A Model of Raw Horse Mackerel Consumption in Japan

The aim of this study was to evaluate the effects of implemented control measures to reduce illness induced by Vibrio parahaemolyticus (V. parahaemolyticus) in horse mackerel (Trachurus japonicus), seafood that is commonly consumed raw in Japan. On the basis of currently available experimental and survey data, we constructed a quantitative risk model of V. parahaemolyticus in horse mackerel from harvest to consumption. In particular, the following factors were evaluated: bacterial growth at all stages, effects of washing the fish body and storage water, and bacterial transfer from the fish surface, gills, and intestine to fillets during preparation. New parameters of the beta‐Poisson dose‐response model were determined from all human feeding trials, some of which have been used for risk assessment by the U.S. Food and Drug Administration (USFDA). The probability of illness caused by V. parahaemolyticus was estimated using both the USFDA dose‐response parameters and our parameters for each selected pathway of scenario alternatives: washing whole fish at landing, storage in contaminated water, high temperature during transportation, and washing fish during preparation. The last scenario (washing fish during preparation) was the most effective for reducing the risk of illness by about a factor of 10 compared to no washing at this stage. Risk of illness increased by 50% by exposure to increased temperature during transportation, according to our assumptions of duration and temperature. The other two scenarios did not significantly affect risk. The choice of dose‐response parameters was not critical for evaluation of control measures.     

Host plant conspicuousness and the distribution of eggs and larvae in the butterfly,Anthocharis scolymus (Lepidoptera: Pieridae)

Summary We investigated how the distribution pattern of eggs and larval on the host plant,Turritus glabra, was influenced by the oviposition behavior of the pierid butterflyAnthocharis scolymus. Females searched for the host plants visually and they frequently approached taller host plants with sparse surrounding vegetation. After encountering host plants, oviposition behavior of females was independent of host plant characteristics such as height, density, and type of surrounding vegetation. A female laid eggs singly on a host plants. Most females appeared to lay their eggs regardless of the presense of eggs on the host plant. Consequently egg and larva tended to be abundant on conspicuous host plants as measured by height or relative isolation from other plants. However, overcrowding of eggs on an individual host decreased the survival rate of larvae.