First record of the terrestrial predatory leech, Orobdella kawakatsuorum Richardson, 1975 (Clitellata, Hirudinea, Erpobdelliformes), from Moneron Island, Sakhalin Oblast, Russia

The terrestrial predatory leech of the genus Orobdella Oka, 1895 is recorded for the first time from Moneron Island, which is located southwest of Sakhalin, Russia. Morphological characteristics of the Moneron Orobdella clarify its taxonomic identification as O. kawakatsuorum Richardson, 1975, which is indigenous to Hokkaido Island in the Japanese Archipelago. The occurrence data extends the northernmost range of the genus Orobdella and shows that the leech fauna is shared between Moneron Island and Hokkaido.

A new species of the genus Luzulaspis (Hemiptera: Coccomorpha: Coccidae) from Hokkaido Island, Japan

A new species of soft scale insect (Hemiptera: Coccomorpha: Coccidae), Luzulaspis kinakikir Tanaka sp. nov., collected from Carex miyabei (Cyperaceae), on Hokkaido Island, Japan, is described and illustrated based on adult female morphology. The new species, which belongs to the Scotica group of Luzulaspis, is similar to L. filizae Kaydan, 2015, but can be distinguished from it by possessing multilocular pores with fewer loculi; numerous dorsal tubular ducts, obviously wider than the ventral tubular ducts, and by lacking dorsal tubular ducts on the head apex. An updated diagnosis of Luzulaspis and two identification keys, one to the Japanese species of Luzulaspis and the other to the species of the Scotica group of Luzulaspis, are provided.

The evolution of hard tick-borne relapsing fever borreliae is correlated with vector species rather than geographical distance

Background Relapsing fever (RF) borreliae are arthropod-borne spirochetes and some of them cause human diseases, which are characterized by relapsing or recurring episodes of fever. Recently, it has been classified into two groups: soft tick-borne RF (STRF) borreliae and hard tick-borne RF (HTRF) borreliae. STRF borreliae include classical RF agents and HTRF borreliae, the latter of which include B. miyamotoi, a human pathogen recently identified in Eurasia and North America. Results In this study, we determined the genome sequences of 16 HTRF borreliae strains: 15 B. miyamotoi strains (9 from Hokkaido Island, Japan, 3 from Honshu Island, Japan, and 3 from Mongolia) and a Borrelia sp. tHM16w. Chromosomal gene synteny was highly conserved among the HTRF strains sequenced in this study, even though they were isolated from different geographic regions and different tick species. Phylogenetic analysis based on core gene sequences revealed that HTRF and STRF borreliae are clearly distinguishable, with each forming a monophyletic group in the RF borreliae lineage. Moreover, the evolutionary relationships of RF borreliae are consistent with the biological and ecological features of each RF borreliae sublineage and can explain the unique characteristics of Borrelia anserina. In addition, the pairwise genetic distances between HTRF borreliae strains were well correlated with those of vector species rather than with the geographical distances between strain isolation sites. This result suggests that the genetic diversification of HTRF borreliae is attributed to the speciation of vector ticks and that this relationship might be required for efficient transmission of HTRF borreliae within vector ticks. Conclusions The results of the present study, together with those from previous investigations, support the hypothesis that the common ancestor of borreliae was transmitted by hard-bodied ticks and that only STRF borreliae switched to using soft-bodied ticks as a vector, which was followed by the emergence of Borrelia recurrentis, lice-borne RF borreliae. Our study clarifies the phylogenetic relationships between RF borreliae, and the data obtained will contribute to a better understanding of the evolutionary history of RF borreliae.

Forests of Japanese alder in the Russian Far East: the new association of the class Alnetea japonicae Miyawaki et al. 1977

We describe the new association Lycopo lucidi–Alnetum japonicae Korznikov, Verkholat & Krestov 2021 ass. nov. of the Alnus japonica swampy forests of the coastal plains and river valleys in the south of the Primorye Territory of Russia. The association includes two subassociations: Lycopo lucidi–Alnetum japonicae typicum Korznikov, Verkholat & Krestov 2021 subass. nov. and the preliminary delineated Lycopo lucidi–Alnetum japonicae betuletosum davuricae subass. prov. developing on gently sloping foothills with a lateral inflow of moisture and is transitional to zonal broad-leaved forests of the class Quercetea mongolicae Song ex Krestov et al. 2006. The association is classified to the alliance Fraxino–Alnion japonicae Miyawaki et al. 1977 described from Japan and belonging to the order Alnetalia japonicae Miyawaki et al. 1977 and the class Alnetea japonicae Miyawaki et al. 1977. We also validate the name of the association Stellario longifoliae–Alnetum japonicae Ohno in Miyawaki 1988 nom. inval. (art. 5) from Hokkaido Island, Northern Japan.

Environmental DNA revealed the fish community of Hokkaido Island, Japan, after invasion by rainbow trout

In freshwater ecosystems, invasive salmonid fishes can have a significant impact on native fish species. Detecting the invasion and its negative effects is critical for the conservation of native fish communities. We examined the species composition and seasonal changes in the freshwater fish community, including salmonids, on the Kamikawa Plain, Hokkaido Island, Japan, using environmental DNA (eDNA) metabarcoding. We detected 23 fish species in 176 samples collected from 16 sites over 12 months (October 2018 – August 2019). Between 11 and 20 species were detected at each site, including five native salmonids (Oncorhynchus masou, Oncorhynchus keta, Parahucho perryi, Salvelinus leucomaenis leucomaenis and Salvelinus malma krascheninnikova). The invasive alien rainbow trout Oncorhynchus mykiss was detected at all 16 sites and it was the most commonly detected salmonid. Although we found no obvious competitive exclusion of native salmonids by rainbow trout in the study area, the invasive species occurred more often and at more sites than any of the natives. We also determined the occurrence and seasonal changes in the fish community, classified as native salmonids, invasive rainbow trout, Cypriniformes and other benthic fishes. There were fewer species overall in winter, but the sites with higher species richness in winter were on the lower reaches of the river. In addition, we detected domestic invaders, such as the topmouth gudgeon, Pseudorasbora parva, although they were less prevalent than rainbow trout. These results show the effectiveness of eDNA metabarcoding, which can be used for surveying species richness at an ecosystem scale. In particular, the detection of the early stages of establishment and spread of invasive species can be achieved by eDNA monitoring.

Long-term observations reveal the formation process of branching systems of the genus Sasa in Bambusoideae

Clarifying the endogenous processes that construct gross aerial shapes such as branching architecture in plants is crucial to understanding how branching contributes to plant adaptation to environments. Architectural analysis is powerful in decomposing the branching process, by comparing observations of plant growth among closely related taxa. The genus Sasa (Gramineae: Bambusoideae) contains three major sections Crassinodi, Sasa and Macrochlamys. These sections exhibit characteristic branching architectures and are distributed separately across the Japanese archipelago, in relation to macroclimatic conditions such as snow accumulation. Our study aimed to quantitatively reveal the endogenous processes underlying branching architectures in the three sections of Sasa. Long-term observations were carried out branch architectural development on Hokkaido Island from 1979 to 2012, which corresponded to the flowering interval of the genus. The results revealed that the three characteristic branching systems of the genus arise mainly from four endogenous processes (distribution of lateral buds on a culm, internode length arrangement along a culm, determination of the fate of lateral buds, development of branching with culm fragility due to ageing) and their interactions with environmental conditions, especially snow accumulation. These processes are coordinated with each other over the life span of a single shoot in developing branching architecture.

The identity of Psychomyia nipponica Tsuda (Trichoptera: Psychomyiidae), with descriptions of five allied new species from Japan

Psychomyia nipponica Tsuda is a commonly occurring species in Japan, and widely distributed throughout Honshu Island and southwestern Hokkaido Island. The male has very characteristic genitalia that allow its easy separation from other species of the genus. My recent study on the Japanese Psychomyia, however, revealed the presence of several undescribed species closely similar to and possibly confused with P. nipponica. In this paper I redescribe P. nipponica to resolve taxonomic confusion and describe five new species of the genus from Japan: P. pseudonipponica sp. nov., P. curvicacumen sp. nov., P. incisa sp. nov., P. serrata sp. nov. and P. quadridentata sp. nov.