A colony of Solenopsis invicta was first intercepted on Gamman pier, Pusan port in Korea at September, 2017 by Animal and Plant Quarantine Agency. The mitochondrial DNA (mt-DNA) of workers was analyzed and compared with vary libraries of mt-DNA haplotypes to elucidate the origin of the introduced colony with the trade pattern of the Gamman pier. The mt-DNA fragment of 768 bp, which is part of the Cytochrome oxidae I gene, was amplified and sequenced. The results showed that the mt-DNA was in the clade of haplotype 5, which is endemic in southern USA, China, Taiwan, and Australia. More than 60% of containers are imported from China into Gamman pier, it may be possible to assume that the colony was inadvertently invaded through containers from China.

Recently a colony of Solenopsis invicta, the red imported fire ant (RIFA), was intercepted on Gamman pier, Pusan port in Korea by Animal and Plant Quarantine Agency. It has been generally known that RIFA has two social forms as monogyne and polygyne, which showing the behavioral differences between the two forms and dictated by a pheromone binding protein, Gp-9. The social forms of the RIFA colony was revealed as polygyne form, when the GP-9 gene was analyzed by three allelic discrimination assays including Real-Time PCR (RT-PCR), rh-Amp SNP Genotyping, and peptide nucleic acid probe-based RT-PCR in this study.