A new species of the genus Protacallodes Morimoto, 2011 (Molytinae), Protacallodes gracilirostris Tsuji & Yoshitake sp. nov., is described from Japan (Honshu, Kyushu, and the Nansei Islands), based on morphological characteristics including male and female terminalia. Renewed diagnoses for two Japanese species (Protacallodes masumotoi Morimoto, 2011 and Protacallodes ryukyuensis Morimoto, 2011) and a key to all species of the genus are also provided. Additionally, Protacallodes ryukyuensis is newly recorded from Kyushu (Fukuoka, Oita, and Kagoshima prefectures) and the Nansei Islands (Tokunoshima Island and Okinawajima Island), Japan.

We clarified the phylogeny and population structure of foxtail millet (Setaria italica (L.) P.Beauv.) landraces using ddRAD-seq, which also enabled us to focus in detail on Japanese landraces. The results were compared with those of previous phylogenetic studies based on transposon display and genotyping of individual genes involved in domestication and diversification under natural and artificial selection. Foxtail millet landraces were found to cluster into distinct geographical groups. The comparison revealed that certain genes, such as Heading date 1 (HD1) and polyphenol oxidase (Si7PPO), began diverging soon after domestication. In contrast, genes such as Pseudo-response regulator 37 (SiPRR37) appeared to have differentiated before geographic divergence, likely in response to environmental adaptation. However, genes such as Waxy (Wx) loci diversified after geographic separation under human selection. Implication of introgression between geographically distant groups was also observed, for example, between French and East Asian landraces. In Japan, two distinct landrace groups were identified: one closely related to Korean landraces and the other showing genetic similarity to accessions from Taiwan and the Batan Islands of the Philippines. The latter group is predominantly distributed in the Nansei Islands (Okinawa Prefecture), indicating multiple introductions and complex dispersal histories of foxtail millet in Japan.

Abstract Dastarcus kurosawai Sasaji (Bothrideridae: Coleoptera), endemic to the Nansei Islands of Japan, is considered a promising natural enemy for the augmentative biological control of Monochamus alternatus Hope (Coleoptera: Cerambycidae). However, mass-rearing methods for this parasitoid have yet to be fully established. In this study, we evaluated once-frozen Zophobas atratus Fabricius (Coleoptera: Tenebrionidae) pupae as an alternative host and estimated the optimal inoculation density for mass rearing. Parasitism rates were significantly higher using once-frozen Z. atratus pupae than fresh Z. atratus pupae and fresh Psacothea hilaris Pascoe (Coleoptera: Cerambycidae) pupae. Adults reared on once-frozen pupae had slightly shorter forewings than those from P. hilaris , but other developmental traits were comparable. Pupation success and pupal size declined at a 40-larval density, while no significant adverse effects on body size were observed at 10–20 larvae per host. However, at a 20-larval density, the parasitism success rate tended to decrease. Based on these results, we conclude that once-frozen Z. atratus pupae are suitable as a substitute host for mass rearing of D. kurosawai , and that approximately 10 larvae per host represents the optimal inoculation density for balancing production efficiency, parasitism success, and parasitoid quality.

Abstract To date, there are no records of appendicularian assemblages or associated investigations in the waters adjacent to the Kuroshio Current around the Nansei Islands, Japan. In this study, plankton samplings were conducted with a North Pacific Standard net hauled vertically from a depth of 200 m to the surface to investigate the appendicularian community structure in such waters. Five species were newly recorded in the western North Pacific, each representing a new geographical record for the region. The new records include Fritillaria aequatorialis, Fritillaria pacifica, Fritillaria pellucida omani, Appendicularia tregouboffi , and Kowalevskia oceanica , which belong to appendicularian families Fritillariidae and Kowalevskiidae. Among them, F. aequatorialis, A. tregouboffi , and K. oceanica represent the first records in the entire Pacific Ocean. Owing to the under sampling of appendicularian assemblages in tropical and subtropical waters in the Pacific Ocean and a lack of systematic quantitative and qualitative research on this topic, these species might have been overlooked for a long time in Japanese waters.

Wedge-tailed Shearwaters Ardenna pacifica and Swinhoe's Storm Petrels Hydrobates monorhis are passage migrants around the Nansei Islands, Japan. However, their detailed distribution in relation to breeding sites have not been thoroughly investigated. We summarized their records collected during our surveys conducted from July to September between 2009 and 2024 and the historical records of photograph and specimens. Most of Wedge-tailed Shearwaters (97% of 537 individuals at 41 observations) were the dark morph; suggesting that most individuals migrating to the waters around the Nansei Islands likely originate from breeding populations in the regions south of 10°N. A total of 10 observations, including 30 individuals, of Swinhoe's Storm Petrel were recorded mainly during their breeding season and some of them showed molt patterns of breeding adults, suggesting the possibility of breeding in the Nansei Islands.

The sweet potato weevil, Cylas formicarius（Fabricius）（Coleoptera: Brentidae）, was detected in October 2022 in Hamamatsu City, Shizuoka Prefecture, Japan, with eradication completed in November 2024 through emergency pest control under the Japanese Plant Protection Act. To determine its origin, we analyzed genetic variation in the mitochondrial cytochrome c oxidase subunit I（mtCOI）gene of 2,024 individuals from 20 countries, including Japan. In total, 158 mtCOI haplotypes were identified worldwide, with 94 detected in 1,729 individuals from 47 geographical populations in Japan. A maximum likelihood phylogenetic tree revealed 11 clades（Clades A–K）, with Japanese haplotypes distributed among three clades: Clades A（Nansei Islands and Taiwan）, C（Ogasawara Islands, China, Hong Kong, Fiji, and Australia）, and J（Minamitorishima Island and the Philippines）. All 24 individuals collected from 10 sites in Hamamatsu City shared the same haplotype within Clade C. These results suggest that the invasive population of C. formicarius, which occurred in Hamamatsu City, originated from a single source, possibly the Ogasawara Islands or another country.

The Alpinia species (A. intermedia, A. zerumbet, A. formosana, A. uraiensis, and unidentified strains native to the Daito Islands), which are native to the Nansei Islands, Japan are ornamental plants that can be used as resources to produce seasonings and antibacterial and antiviral substances. Despite the usefulness of these plants, little scientific research has been conducted on their phylogenetic relationships. In this study, their phylogenetic relationships were examined based on genomic and chloroplast DNA polymorphisms, repetitive sequence abundance, and cytogenetic perspectives. The results indicated that A. formosana is most likely the outcome of a hybrid of A. zerumbet and A. intermedia, and the unidentified strains native to the Daito Islands are the outcomes of a hybrid of A. zerumbet and A. uraiensis. Immunostaining with a newly produced anti-centromere-specific histone H3 (CENH3) antibody revealed that the number of chromosomes in these species was 2n=48.

Falsanathelges grandiceps sp. nov. is described as an abdominal bopyrid of hermit crab Cancellus mayoae in the Nansei Islands, southwestern Japan. Falsanathelges grandiceps sp. nov. is distinguished from its congeners by the following combination of characters: head longer than broad, head approximately one-fourth of body in length head anterior margin convex, ischium and basis of all pereopods without large lobe in female, pleopods and lateral plates broadly ovate, base of uropods without peduncle, and biramous uropods in female and pleon subovate, all pleomeres fused with no lateral indication of segmentation, and pleon posterior margin with a pair of tubercles in male. This is the third species described in the genus, and the first species of the genus being found in Japan. The others in the genus are from Malaysia, Indonesia, Philippines and Taiwan. An amended generic diagnosis and key to species are provided.

Pacific bluefin tuna (PBF, Thunnus orientalis), migrate widely throughout the north Pacific Ocean during all life stages. However, studies on the migration of adult fish in the northwestern Pacific Ocean, where spawning occurs, are limited. This study investigated the post-spawning migration and habitat use of PBF from the major spawning grounds of the Nansei Islands (approximately 23–31° N), Japan, using pop-up satellite archival transmission (PAT) tags. The PAT tags were deployed on 15 PBF individuals (estimated fork lengths: 170–260 cm) in the late spawning season (May–June) of 2021, and tracking data were collected for 3–103 days. Four tagged PBF individuals moved > 2,500 km north to the Kuroshio-Oyashio transition region at high latitudes (40° N) in July–September, immediately after the spawning season. During this northward movement, these PBF showed a spatiotemporal change in their vertical behavior, adapting to regional thermal habitat differences. At low latitudes near the spawning grounds (23.6–29.6° N), the PBF dived to deep depths (mean: 162.8 m) to avoid the warm surface layer (mean: 28.6 °C); however, once they reached higher latitudes (36.6–44.9° N), they spent most of their time in the cool surface layer (mean: 18.5 °C; 22.3 m). Our findings suggest that adult PBF move from spawning grounds to physiologically suitable low-temperature, food-rich waters through long-distance movements, and then exhibit a habitat preference behavior characterized by repeated short-distance movements in response to the feeding environments at high latitudes.

ABSTRACT Pumice is a pyroclastic material of low density and is occasionally buoyant in water. When it erupts from submarine volcanoes, it can drift long distances and wash ashore at remote beaches. Pumice from the eruption of Fukutoku‐Oka‐no‐Ba volcano in the Izu–Bonin arc in October 2021 drifted for about 2 months over a distance of > 1300 km onto the Nansei Islands of Japan, disrupting shipping, fishing, and coastal ecosystems. In March 2024, large amounts of dark brown to black pumice washed ashore on these islands, and subsequently in the Kanto area of Japan. Their geochemical and petrographic characteristics were examined, and Ioto volcano, which is one of the most active volcanoes in Japan, was identified as a possible source based on these characteristics. Small amounts of similar pumice clasts drifting ashore in the Nansei Islands during 2022–2023 were also identified as originating from Ioto volcano. Since July 2022, volcanic activity involving magma eruption has occurred off the southeast coast of Ioto, where pumice rafts generated by the eruptions have been observed. Drift simulations indicate that pumice ejected from Ioto could reach the Nansei Islands, where it is widely distributed. The observation of pumice drifting along the coast of these islands thus provides information on the dispersal of pumice to other parts of Japan, with sources effectively identified through their chemical composition. The results contribute to our understanding of the eruption histories of submarine volcanoes in the Izu–Bonin arc.

In this study, we estimated prey availability in the early life stages of Pacific bluefin tuna (PBF) based on their mouth gape size, collected in two spawning grounds, the Pacific Ocean around the Nansei Islands and the Sea of Japan. The increase in mouth gape sizes was investigated using laboratory-reared PBF larvae and juveniles. Thereafter, we compared the mouth gape size of PBF with the body size of prey larvae, including PBF, collected in field surveys in the spawning grounds of PBF conducted in 2017 and 2018. We defined the collected larvae smaller than the mouth gape, mouth width, and 1/3rd the body length (BL) of PBF as potential prey larvae (PPL), which have the potential of being captured and ingested by PBF. The number of PPL in each sampling station was estimated for PBF of 8, 10, 15, 20, and 30 mm BL size classes as predatory PBF. The density of PPL increased for PBF larger than 20 mm in BL, suggesting that prey availability could change drastically for PBF larvae and juveniles larger than 20 mm BL.

A new species of the genus Cheiracanthium C. L. Koch 1839, Cheiracanthium minutum sp. nov. (♂♀), is described on the basis of specimens collected from the Nansei Islands, Japan. The photos of the habitus, copulatory organs and illustrations are provided. In addition, the DNA barcode sequence of this species is also provided.

Two new species within the genus Euochin Prószyński 2018, collected from the Nansei Islands, Japan, are described as Euochin japonica Suguro sp. nov. and E. yaeyamana Suguro sp. nov. The genus Euochin is newly recorded in Japan. The two new species can be distinguished from their congeners based on the morphology of the retromarginal tooth and the genitalia.

First records of the subgenus Eurhipidia from Japan, with two new species (Diptera, Limoniidae, Rhipidia )

Priority sites for coral aquaculture in Kume Island based on numerical simulation

Sugarcane (Saccharum spp. hybrids) and its processed products have supported local industries such as those in the Nansei Islands, Japan. To improve the sugarcane quality and productivity, breeders select better clones by evaluating agronomic characteristics, such as commercially recoverable sugar and cane yield. However, other constituents in sugarcane remain largely unutilized in sugarcane breeding programs. This study aims to establish a data-driven approach to analyze agronomic characteristics from breeding programs. This approach also determines a correlation between agronomic characteristics and free amino acid composition to make breeding programs more efficient. Sugarcane was sampled in clones in the later stage of breeding selection and cultivars from experimental fields on Tanegashima Island. Principal component analysis and hierarchical cluster analysis using agronomic characteristics revealed the diversity and variability of each sample, and the data-driven approach classified cultivars and clones into three groups based on yield type. A comparison of free amino acid constituents between these groups revealed significant differences in amino acids such as asparagine and glutamine. This approach dealing with a large volume of data on agronomic characteristics will be useful for assessing the characteristics of potential clones under selection and accelerating breeding programs.

Luciogobius griseus n. sp., belonging to the Luciogobius platycephalus complex, is described on the basis of 40 specimens from the Nansei Islands, southwestern Japan (subtropical area). The new species is generally found in intertidal gravel sediments subjected to freshwater runoff from springs on coastal lines or river mouths and is characterized by the following combination of characters: total second dorsal-fin rays 912 (modally 11); total anal-fin rays usually 1214 (modally 13); pectoral-fin rays 1215 (modally 13); vertebrae 17 or 18 + 23 or 24 = 4042 (18 + 23 = 41); uppermost 24 (23) rays on pectoral fin free; 812 pectoral-fin rays branched (uppermost free rays and sometimes lowermost ray unbranched); pectoral-fin membrane not strongly concave anteriorly (except for free rays); pelvic fins united, forming a disk; head relatively short, 13.920.8% of standard length (SL); relatively short pre-pelvic fin, length 14.422.1% of SL; relatively long pre-dorsal fin, length 68.972.9% of SL; relatively long pre-anal fin, length 63.567.7% of SL; relatively short pelvic fin, length 2.84.7% of SL; distance between posterior end of pelvic fin and anus relatively long, 32.036.4% of SL (aforementioned morphometrics each distinguishing L. griseus n. sp. from other species in the L. platycephalus complex); and fresh specimens with greenish dark brown or gray body. A key to the L. platycephalus complex is provided, together with limited descriptions and remarks on the other two members of the complex.

We evaluated the detection efficiency and location accuracy of lightning discharges in Japan using Blitzortung.org, a volunteer-based network for locating lightning discharges from sferics measured by very low frequency (VLF) electromagnetic receivers that have been deployed worldwide in recent years. A comparison of the flash rate (the detected lightning rate per area and period) from Blitzortung.org with that from the satellite-based OTD/LIS and the ground-based World Wide Lightning Location Network (WWLLN) observations showed that Blitzortung.org clearly observed intense lightning activity in and around the Kanto area, including Tokyo, in summer, which is typical of Japanese lightning activity. However, it did not clearly observe lightning activity in and around the Nansei Islands, including Okinawa. Conversely, Blitzortung.org observed winter lightning activity in the Hokuriku area and off the Kanto. In addition, event studies have compared the detection efficiency and location accuracy of Blitzortung.org with those of the Japanese Lightning Location Network (JLDN) to infer their absolute values. The latest detection efficiency of Blitzortung.org in the Kanto area was estimated at roughly 90%. The mean location accuracy was estimated at up to 5.6 km.

We revised the fauna of goblin spiders (Oonopidae) in the Nansei Islands, southwest Japan, and recognized 12 species of seven genera. Eleven of them were described species, namely, Gamasomorpha cataphracta Karsch, 1881, Heteroonops spinimanus (Simon, 1892), Ischnothyreus narutomii (Nakatsudi, 1942), Ischnothyreus peltifer (Simon, 1891), Ischnothyreus velox Jackson, 1908, Opopaea cornuta Yin & Wang, 1984, Opopaea deserticola Simon, 1892, Opopaea syarakui (Komatsu, 1967), Orchestina flava Ono, 2005, Xestaspis parmata (Thorell, 1890), and Xyphinus karschi (Bsenberg & Strand, 1906). A new species is described under the name of Ischnothyreus ogatai sp. nov. This paper provides photographs of each oonopid species, notes on habitat and distribution, and keys to the species. A detailed description of I. ogatai sp. nov. (for both sexes), morphological data regarding three species newly added to the Japanese fauna (X. parmata, I. velox, and O. cornata), and additional data on the genital morphology of G. cataphracta are also presented.

Revisiting the spawning fraction of Pacific bluefin tuna (Thunnus orientalis) caught in the Sea of Japan based on diurnal changes in spawning markers