Undesirable dispersal via a river pathway of a single Argentine ant supercolony newly invading an inland urban area of Japan.

Invasive ants pose a risk to human well-being and social/ecosystem stability. Linepithema humile Mayr is among the most damaging invasive ants worldwide. Most L. humile populations invade ports/wharfs isolated from surrounding landscapes, but unfortunately, a new population was discovered in an inland urban area (Nara Prefecture) of Japan in 2021. In this study, first, the supercolony type of the Nara L. humile population was identified via a hostility test, and then its distribution pattern was characterized. In aggression tests between L. humile from Nara and four supercolonies (haplotypes LH1, LH2, LH3, LH4), this ant showed extremely strong hostility against all supercolonies exept LH2, which was detected only in Japan in its introduced range. In Nara, L. humile was abundant in and around the urban river. Simulations revealed that using this environment for movement/dispersal increased the annual dispersal ability by 14 times compared with that achieved via ground (125 m), as mentioned in the literature. Therefore, river channels can serve as major pathways of long-distance dispersal for L. humile invading inland urban areas. Since applying chemical strategies around rivers is problematic, preventing L. humile from moving to rivers from initial invasion sites is crucial.

A new species of the genus Crossodonthina (Collembola: Neanuridae: Neanurinae: Lobellini) from Yonaguni-jima in southwest Japan.

We describe a new species of Collembola, Crossodonthina elegans sp. nov., collected from Yonaguni-jima, southwest Japan. This new species differs from other known congeners because it has an unusual white or yellow color pattern on Ant. I and Th. I. It is similar to C. laterisensillata Ohira, Kataoka, Tanooka & Nakamori, 2022, in the structure of mouthparts, 3 + 3 eyes, cephalic chaeta O present, and tubercles De and Dl separated on Abd. V. However, it is easily distinguished from the latter species to maxilla without ciliated lamella, cephalic tubercle Dl separated from L and So, 5 chaetae of tubercle L on Abd. I and III, and macrochaetae apically rounded. We provide the key to all species of the genus and discuss the unique color pattern of the new species among the tribe Lobellini.

Four new saproxylic species of Paranura Axelson, 1902 (Collembola: Neanuridae: Neanurinae) from Japan.

Four new saproxylic species of the genus Paranura from Nagasaki, Nara, and Niigata provinces of Japan are described and illustrated in this paper. Paranura tsushimaensis sp. nov. is characterized by a dark blue body color, Abd. V four times as long as Abd. VI, 3+3 eyes, three ocular chaetae on the head, four ordinary chaetae De on Th. III, two ordinary chaetae Di on Abd. V, and all dorsal chaetae of Abd. VI in a unique reticulated plate. P. nakamurai sp. nov. is identified by its yellowish white body color, 2+2 eyes, tubercle Af on the head with two reticulated tubercles, and tubercles Di on Abd. V fused. P. alpicola sp. nov. is characterized by its yellow body color, 3+3 eyes, presence of complete chaetotaxy in the central area of the head, Th. IIIII with two and three ordinary chaetae De respectively, and tubercles Di on Abd. V separate. P. convallis sp. nov. is identified by its orange body color, 3+3 eyes, head without chaeta O, three mandibular teeth, and Th. IIIII with three and four ordinary chaetae De respectively. A key for all species of the genus Paranura is provided.

First report of the genera Paralobella and Blasconura (Collembola: Neanuridae: Neanurinae) from Japan with the description of three new species.

This study reports the first record of the genera Paralobella Cassagnau Deharveng, 1984 and Blasconura Cassagnau, 1983, three new species from Kuchinoerabu-jima and Miyako-jima of Japan, respectively. Paralobella kuchierabu sp. nov. can be distinguished from all known genus members by distinct morphological characteristics: yellow body color, mandible with 3 teeth, presence of chaeta O on head, and tubercle De of Th. IIIII with 5 (4+s) chaetae, tubercle Di of Th. I with 1 chaeta, tubercles De and Dl of Abd. V separated. Blasconura triangulum sp. nov. is characterized by a tubercle Fr fused to An, unguis without an inner tooth, and 2 very closely placed tubercles Di on head. Blasconura cordis sp. nov. is unique in the genus, with a tubercle An fused to Cl. Other characteristic features of the species are the absence of chaeta O on head, tubercle Oc with 3 chaetae, Ant. I with 7 chaetae, and tubercle De of Th. III with 5 (4+s) chaetae. A key to all species of the genus Paralobella and Blasconura is provided.