Parasitization by an endoparasitoid wasp, Cotesia plutellae, extends a larval period of Plutella xylostella and inhibits a larva-to-pupa metamorphosis. To determine antimetamorphic parasitic factor(s) in this host-parasitoid interaction, an effect of its symbiotic polydnavirus, Cotesia plutellae bracovirus (CpBV), was investigated by injecting purified virus particles to nonparasitized larvae of P. xylostella. Larvae injected with CpBV exhibited antimetamophosis in a viral dose-dependent manner. Also, the susceptibility to the viral injection was increased at young larval stages. Parasitized or virus-injected larvae shwed significant decrease in cell size of prothoracic gland and reduction in expression of ecdysone receptor (EcR) gene. However, they increased and maintained expression of insulin receptor (InR) gene. Twenty four CpBVsegments were individually injected to nonparasitized larvae. Only two segments (S22 and S27) had significant antimetamorphic effect. Subsequent RNA interference using double stranded RNA (dsRNA) was performed in each of encoded genes in each segment. Protein tyrosine phosphatase, ELP, and three hypothetical genes were determined to be antimetamorphic factors.

Parasitization by Cotesia plutellae inhibits pupal metamorphosis of diamondback moth, Plutella xylostella. Two questions are raised : (1) which parasitic factor(s) is responsible for the antimetamorphosis and (2) how the parasitized larvae are altered in endocrine signals. This study addressed both questions. When C. plutellae bracovirus (CpBV), a parasitic factor of the wasp, alone was injected to nonparasitized P. xylostella larvae, it significantly inhibited pupal metamorphosis in a dosedependent manner. Corpora allata (CA) and prothoracic gland (PTG) were compared in both nonparasitized and parasitized P. xylostella. In both groups, size and shape of CA were not different. However, PTG was detected on prothoracic tracheal trunk in nonparasitized larvae, but not detected in parasitized. CpBV injection to nonparasitized larvae inhibited the growth of PTG. Transcriptional factor, broad complex, was partially cloned and expressed in nonparasitized P. xylotella. In parasitized or CpBV-injected larvae, broad complex gene was not expressed during late larval stage.

Better understanding the mechanism of black ice occurrence on the road in winter is necessary to reduce the socio-economic damage it causes. In this study, intensive observations of road weather elements and surface information under the influence of synoptic high-pressure patterns (22nd December, 2020 and 29th January, and 25th February, 2021) were carried out using a mobile observation vehicle. We found that temperature and road surface temperature change is significantly influenced by observation time, altitude and structure of the road, surrounding terrain, and traffic volume, especially in tunnels and bridges. In addition, even if the spatial distribution of temperature and road surface temperature for the entire observation route is similar, there is a difference between air and road surface temperatures due to the influence of current weather conditions. The observed road temperature, air temperature and air pressure in Nongong Bridge were significantly different to other fixed road weather observation points.