Abstract / Introduction / Summary:
In total, 28 ant species belonging to 16 genera in 4 subfamilies were collected from 2 habitat types, i.e., port waterfront areas (simply ‘ports’) and residential areas, on the islands of Mi-shima, Kuro-shima, Iwo-jima and Take-shima, Kagoshima Prefecture, southwestern Japan. Among the 28 species, 23 were collected from ports. Five species, Nylanderia flavipes, Pheidole fervens (alien), Ph. noda, Pristomyrmex punctatus, and Tetramorium bicarinatum (alien), were collected from both the ports and residential areas on all of the three islands.
Eight species are new to particular islands, namely, Tapinoma melanocephalum (alien) on Kuro-shima, Nylanderia amia (alien) on Kuro-shima and Take-shima, Aphaenogaster osimensis on Take-shima, Cardiocondyla sp. A (alien) on Iwo-jima, C. sp. B (alien) on Iwo-jima, Ph. indica (alien) on Take-shima, Ph. pieli on Take-shima and Tetramorium lanuginosum (alien) on Iwo-jima. Of the 28 species, eight (28.6%) were alien ants.
The dominant species measured by the frequency of occurrence at honey baits (n = 90) were Ph. fervens (0.56), followed by N. flavipes (0.35) and Ph. noda (0.32).
Similarity of species composition calculated by Nomura-Simpson’s Coefficient was the greatest (0.77) between Osato Port (Kuro-shima) and Take-shima Port. The ratio of the alien ants at ports on the Osumi Islands and Mi-shima surveyed so far was the greatest (50.0%) at Iwo-jima Port, while the lowest (21.4%) at Miyanoura Port on Yaku-shima.