Vollenhovia emeryi (Formicidae: Myrmicinae) is divided into two morphs based on the wing length of the queen caste: the long-winged with a normal wing and the short-winged with the aberrant short wing. The phylogenetic analysis shows that the short-winged is derived from the long-winged. In Korea, only the long-winged morph is infected with Wolbachia while the short-winged is devoid of the bacterium suggesting that the short-winged evolved the resistance to the bacterial infection. Intriguingly, some Japanese short-winged colonies proved to still be infected with the bacterium. We hypothesized that the infected Japanese short-winged is the intermediate form in the process to complete cure. However, the data of the MLST and the measurement of Wolbachia density did not support our hypothesis. Our further experiment using microsatellite markers shows that the infected Japanese short-winged shows the similar genetic background to the long-winged. In this presentation we will discuss the potential resistance evolution in the Korean short-winged and future research direction at the genome level.

In this study, nitrogen ions were implanted into STS 316L austenitic stainless steel by plasma immersion ion implantation (PIII) to improve the corrosion resistance. The implantation of nitrogen ions was performed with bias voltages of −5, −10, −15, and −20 kV. The implantation time was 240 min and the implantation temperature was kept at room temperature. With nitrogen implantation, the corrosion resistance of 316 L improved in comparison with that of the bare steel. The effects of nitrogen ion implantation on the electrochemical corrosion behavior of the specimen were investigated by the potentiodynamic polarization test, which was conducted in a 0.5 M H2SO4 solution at 70 oC. The phase evolution and texture caused by the nitrogen ion implantation were analyzed by an X-ray diffractometer. It was demonstrated that the samples implanted at lower bias voltages, i.e., 5 kV and 10 kV, showed an expanded austenite phase, γN, and strong (111) texture morphology. Those samples exhibited a better corrosion resistance.