PURPOSES : Thermal cracking (also called low-temperature cracking) is a serious stress for asphalt pavement, especially in eastern South Korea, the northern USA, and Canada. Thermal cracking occurs when the level of thermal stress exceeds the corresponding level of low temperature strength of the given asphalt materials. Therefore, computation of thermal stress is a key factor for understanding, quantifying, and evaluating the level of low-temperature cracking resistance of asphalt pavement. In this paper, two different approaches for computing thermal stress on asphalt binder were introduced: Hopkins and Hamming’s algorithm (1967) and the application of a simple power-law function. All the computed results were compared visually; then the findings and recommendations were discussed. METHODS: Thermal stress of the tested asphalt binder was computed based on the methodology introduced in previous literatures related to viscoelastic theory. To perform the numerical analysis, MATLABTM 2D matrix-correlation and Microsoft Excel visual basic code were developed and used for the function fitting and value-minimization processes, respectively. RESULTS : Different results from thermal stress were observed with application of different computation approaches. This variation of the data trends could be recognized not only visually but also statistically. CONCLUSIONS: It can be concluded that these two different computation approaches can successfully provide upper and lower limits (i.e. boundaries) for thermal stress prediction of a given asphalt binder. Based on these findings, more reliable and reasonable thermal stress results could be provided and finally, better pavement performance predictions could also be expected.

Mature silkworm of Bombyx mori is known to contain various functional materials. However, it is too hard to chew or digest for humans when it is cooked or lyophilized. In Korea, the Rural Development Administration recently developed and patented a method for making mature silkworms edible. In this study, therefore, we examined the effects of a larval powder of steamed mature silkworm (SMSP) on skin pigmentation and melanogenesis. For elucidating the depigmenting activity, lightness of a designated site on the murine dorsal skin was measured in vivo. During the experiment, hyperpigmentation was induced on the skin by cumulative exposure to ultraviolet B (UVB) irradiation. At the end of the experiment, melanin production on the skin was visualized by Fontana-Masson staining. Orally administered SMSP of pistachio cocoon strain for at least a month or longer significantly and reduced abnormal pigmentation caused by UVB on the murine dorsal skin. SMSP also showed a potential anti-melanogenic efficacy in modulating UVB-induced hyperpigmentation. Taken together, SMSP was identified as a potential candidate for a novel anti-melanogenic agent, which showed depigmenting efficacy against UVB-induced hyperpigmentation in vivo when administered orally.

Different laboratory strains of Drosophila melanogaster are reported to differ considerably in their physiology, behavior, and life-histories, due to their adaptations to different laboratory conditions. Recent advances in insect aging research have highlighted the importance of protein:carbohydrate (P:C) balance as a key dietary determinant of lifespan and other components of fitness, but it remains unexplored whether P:C balance affects the fitness-related traits of D. melanogaster in a strain-specific manner. The purpose of this study was to compare the life-history consequences of six different laboratory strains of D. melanogaster (three Canton-S substrains, w1118, yw, and Oregon-R) allocated to four synthetic diets differing in P:C ratio (1:16, 1:4, 1:1, or 4:1). Five components of fitness (lifespan, fecundity, larval viability, development time, and body mass) were recorded from flies maintained at 25oC under L:D 12:12 photoperiod. All strains exhibited qualitatively similar responses to dietary P:C balance, with the increase in P:C ratio being associated with shortened lifespan and improved egg production. In all strains, fly larvae confined to P:C 1:16 suffered high mortality, retarded growth, and reduced body size. As indicated by significant diet×strain interactions for all measured fitness components, the magnitude of such diet effect varied among different laboratory strains in D. melanogaster. Possible explanations for such strain differences are discussed.

Diet and temperature are the two most critical environmental factors affecting life-history traits in insects, but the combined effects of these factors have been rarely investigated. In this study, various life-history traits were recorded from adult and larval Drosophila melanogaster fed on one of eight synthetic diets differing in protein:carbohydrate ratio (P:C=1:16, 1:8, 1:4, 1:2, 1:1, 2:1, 4:1, or 8:1) under one of six ambient temperatures (13, 18, 23, 28, 31, or 33oC). The patterns of adult and larval life-history traits expressed across 48 diet-by-temperature combinations were visualized using thin-plate spline technique and the presence of any significant linear, quadratic, and correlational effects of diet and temperature on trait expressions was analyzed using a second-order polynomial multiple regression. Life-history traits exhibited qualitatively different responses to variations in both diet and temperature, with the maximal expression of each trait being achieved at a completely divergent region of the diet-temperature fitness landscape. In adult females, for example, lifespan was maximized at P:C 1:16 under 13oC, but fecundity was maximized at P:C 4:1 under 28oC. These results provide empirical support for the emerging notion that environmental factors, such as diet and temperature, can mediate life-history trade-offs in insects.

We conducted quarantine insect species diversity monitoring using DNA barcoding with 517 lepidopteran samples that were obtained from quarantine inspections of foreign vessels entering Korea. The DNA barcode of each sample was treated as a molecular operational taxonomic unit (MOTU). For species delimitation and species identification of the analyzed samples, we applied a 2% cutoff rule and then identified with using BLAST of NCBI GenBank and BOLD System ver. 3.0. Consequently, 517 analyzed samples were delimited as 214 putative species across 20 families. Of these 214 putative species 145 (368 samples) were considered taxonomically identified if the closest BLAST match was no more than 2% different. Therefore the number of samples that were identified to the species level was relatively low, at approximately 71%. 115 of the 145 species were known in Korea. Of the 30 species that were not known in Korea, three, i.e., Noctua pronuba (Noctuidae), Orthosia hibisci (Noctuidae), and Pieris brassicae (Pieridae), were checked as ‘Regulated pests’ in Korea. We suggest that the three regulated pest species could be prevented from being introduced to Korea if monitoring of the vessels that pass the navigation route that contains these three species is performed consistently. Therefore, we suggest that the monitoring of quarantined insect pest enables the prevention of the introduction of alien species.

Oak wilt disease caused by Raffaelea quercus-mongolicae is one of the serious diseases in Korea. Infected trees showed wilting and discolourations on the cambium when the bark of a tree is peeled, since it deters moisture migration. Raffaelea quercus-mongolicae is vectored by Platypus koryoensis. In this regard, it was assumed that there might be a positive correlation between the number of gallery generated by P. koryoensis and the level of damage on the infected tree by the oak wilt disease. In order to link the occurrence of dead oak trees with the number of galleries produced by P. koryoensis, five regions (Incheon, Anyang, Gwangmyeong, Icheon and Gimhae) were selected in Korea. The number of galleries on Mongolian oaks produced by attack of P. koryoensis was counted in four directions between 50cm and 100cm from the ground level. Furthermore, Vegetation was investigated from the area where the oak wilt disease occurred, and a data logger was set up to collect data including temperature and relative humidity in each region at the elevation between 100~200m. A significant difference was observed in the number of galleries made by the insect vector between dead trees and trees infected with oak wilt disease, while no difference was observed from the vegetation on the area investigated. We will further investigate as to whether climate factors might contribute to the density and the successful invasions of the insect vector to the oak trees.

The hypopharyngeal gland (HPG) of the honeybee worker produces royal jelly (RJ) and has a developmental cycle closely related to the division of labor. In this study, we investigated to compare the HPG acini diameter of differently aged worker bees with high royal jelly producing colony (HRC) or less producing colony (LRC). Additionally, we also evaluated whether the fresh weight of the head is a reliable indicator of the developmental status of HPG. The HRC showed a significantly higher RJ production about two-times as compared with those of the LRC. We measured the HG-diameters on days 1, 3, 6, 9, 12, 15. The microscopic analysis revealed that the acini size of the HRC was significantly larger than the LRC. In addition, the acini diameter of HRC was 15% longer than the LRC on the first day after emerging. It was shown that the fastest development during 3 days which is preparing for nurse the brood. The HPG acini diameters increased in both colonies in a similar fashion until day 12 and then decreased. We also compared the fresh head weight of the experimental colonies, differences were similar to the development of HPG. Therefore, high royal jelly production may have a positive correlation between HPG acini size and the fresh head weight.

The tribe Cyllodini is reviewed as 10 species of three genera from Korea, including two new species Pallodes sp. nov. and Cyllodes sp. nov. and one newly recorded species Neopallodes vicinus Grouvelle 1892. A key to species from Korea, comments on external and genital structures, biology, illustrations of structures, including the genitalia of both male and female of the Korean Cyllodini species are provided.

Cylapine plant bug, Bothriomiris gotohi Yasunaga, 2000 and Peritropis advena Kerzhner, 1972 is reported from Korean peninsula for the first time. Morphological diagnosis for the genus is provided with dorsal habitus, female and male genital structure of Korean Cylapinae species. Also, keys to genera and to species of Korean Cylapinae provided for proper identification.

The Japanese pine bast scale, Matsucoccus matsumurae (Kuwana, 1905), is a destructive pest of pine trees in America, East Asia and Northern Europe. The spread of damage to black pine trees, Pinus thunbergii, of M. matsumurae was reported from all southern, and some eastern and west costal regions in Korea, under the name of M. thunbergianae which was newly described by Miller & Park (1987) as a new species. Historically, M. thunbergianae was synonymized with M. matsumurae by Booth & Gullan (2006), on the basis of molecular sequence data. However, the supporting data for the synonym is unavailable in any DNA database, such as GenBank and BOLD. Moreover, M. thunbergianae have been still used to the resent scientific studies in Korea. Here, we performed morphological and molecular comparison to review the result of Booth & Gullan (2006), using M. matsumurae from Fukuoka, Japan and topotype materials of M. thunbergianae from Goheung, Korea. Our data supported the opinion of Booth & Gullan (2006) following results: The morphological features of adult female and male of M. thunbergianae are identical to those of M. matsumurae. Also, DNA sequences (COI, 18S rDNA and 28S rDNA) of M. thunbergianae showed identical or very low genetic distances with those of M. matsumurae. From the regional sampling in Korea, M. matsumurae was newly found in Jeju and Seoul.