Collected Tramea virginia (Rambur, 1842) in Nishinomiya City, Hyogo Prefecture
Tramea virginia (Rambur, 1842) is a dragonfly that has been confirmed to be established in the regions of Shikoku and Kyushu and southward within Japan. One notable aspect of its ecology is its high mobility, which allows it to travel far from its original habitat and therefore has been recorded widely across the Japanese archipelago. In Hyogo Prefecture, records of Tramea virginia (Rambur, 1842) are concentrated in the southern part, with a few records in the north. The author reports having collected several specimens of Tramea virginia (Rambur, 1842) in Nishinomiya City, Hyogo Prefecture, in 2023.
1.Collection record (listed in the order of collection date, collection location, collector)
2♂1♀ 13.IX.2023.Naruohama,Nishinomiya-shi,Hyogo Pref.M.kozen Collection and Storage(Fig.1)
2.Environment of the collection site
The collection site is a park constructed on reclaimed land facing the sea. The park’s environment includes artificial pools and grassy areas, as well as a pond surrounded by planted trees (Fig.2, Fig.3).
3.Situation during collection
The weather was clear with temperatures around 30°C. At approximately 7 AM, upon visiting the park, a male specimen of Tramea virginia (Rambur, 1842) was discovered perched at the top of a tree facing the pond and was collected. As I continued to stroll around the park, I spotted a male individual flying among Pantala flavescens (Fabricius, 1798) in a grassy area and collected it. Furthermore, a female individual perched at the top of a tree in the parking area adjacent to the park was also collected. Despite a thorough investigation of the park afterward, no additional specimens were found.
4.Discussion of the present record
The author has collected numerous specimens of Tramea virginia (Rambur, 1842) in 2022 and 2023 along the reclaimed lands and parks stretching from Osaka City to Takaishi City along Osaka Bay. Among the collected specimens were both mature individuals and several immature ones, which appeared to have emerged only a few days prior. This suggests a temporary generational continuation from individuals that had migrated from other locations. Against this backdrop, explorations were conducted for the arrival of Tramea virginia (Rambur, 1842) in Nishinomiya City, Amagasaki City, Ashiya City, and Kobe City in Hyogo Prefecture. No specimens were found in 2022, and in 2023, apart from this record, only one male was discovered in Okuike Town, Ashiya City. This suggests that the specimens found in Hyogo Prefecture are likely migrants from other areas, with potential sources of origin along the Osaka Bay.
In addition to Tramea virginia (Rambur, 1842), the park, which is a reclaimed area, also recorded other widespread dispersal species such as Trithemis aurora (Burmeister, 1839) and Sympetrum fonscolombii (Selys, 1840). This suggests that artificial green spaces created on reclaimed lands like this park serve as crucial landing environments for broadly mobile species like Tramea virginia (Rambur, 1842), which may use these sites as initial landing spots after crossing seas. It is considered valuable for monitoring the dispersal and settlement of such species in newly developed habitats. The continued observation of the dynamics of Tramea virginia in the Hanshin area (between Osaka and Kobe) is thus warranted.
Abstract Tramea virginia (Rambur, 1842) is a dragonfly confirmed to be established in regions from Shikoku and Kyushu southwards within Japan. A key ecological trait of this species is its high mobility, which allows it to travel far from its original habitats, leading to widespread records across the Japanese archipelago. In Hyogo Prefecture, records of this species are predominantly found in the southern region, with a few in the north, most of which are believed to be instances of migration from other areas. The author has collected several specimens of Tramea virginia (Rambur, 1842) in Nishinomiya City, Hyogo Prefecture, in 2023 and will discuss these findings and observations.
