First record of <i>Pheidole fervens</i> Smith, 1858 (Hymenoptera, Formicidae) from Honshu-Island in Japan, its distribution, and its impact on the native ant species

<p>Pheidole fervens Smith was collected at Kyoto City in 2020 for the first time in Honshu Island, Japan. No individual of this invasive ant species was collected between 2016 and 2019 at the invasion area and surrounding one. Ninety-seven and 457 individuals of P. fervens including major workers were captured by traps in 2020 and in 2021, respectively, suggesting that the invasion/establishment had occurred in 2019 or in early 2020. To detect ecological impacts of P. fervens invasion on ant community, we compared collecting rate and number of individuals captured by traps for other ant species between the invasion area and the non-invasion one in 2021. At late November and mid-December 2021, this invasive species was found within a range of about 100 m from north to south and 30–40 m from east to west, and was the dominant ant in the area. Collecting rates of Tetramorium tsushimae Emery and Formica japonica Motschoulsky in the invasion area were lower than those in the non-invasion area in 2021. These results suggested that these two common ant species would be displaced by P. fervens. On the other hand, P. nodus Smith sympatrically inhabited with P. fervens even from 2020 onwards, and no difference was found in mean number of P. nodus individuals captured and in its collecting rate between the invasion area and the non-invasion one. In addition to this, no apparent impact of P. fervens invasion on Nylanderia amia was detected in the present study.</p>