尾瀬・奥鬼怒地域の Pidonia 相とその分布形成について  [in Japanese] Notes on the Lepturine Pidonia Fauna (Coleoptera : Cerambycidae) in the Oze-Okukinu Range, Central Japan, from a Historical Biogeographical Standpoint  [in Japanese]

日本列島の気候の特徴の一つである太平洋側の気候と日本海側の気候の境界に位置する尾瀬・奥鬼怒地域でPidonia相とその垂直分布, 訪花植物, 幼虫の生活を調べた.1974年から行ってきた全国各地でのPidoniaの生態調査とウルム氷期最盛期以降の植生変遷に関する研究を参考に, この地域でのPidonia相の形成について考えた.1. 1993年7月27日から31日の調査で, 合計24種のPidoniaを確認した.2. 落葉広葉樹林のPidoniaは, その分布域が太平洋側または日本海側のどちらかの地域に片寄る種が尾瀬・奥鬼怒地域でみつかった.P. obscurior, P. insuturata, P. semiobscura, P. limbaticollis, P. oyamaeは太平洋側地域を, P. hakusana, P. hayashii, P. miwai, P. takechiiは日本海側地域を中心に分布していた.3. P. insuturataとP. hayashii, P. obscuriorとP. hakusanaのように, 系統的に近縁な種間に対応的分布関係が調査地域内でみつかった.4. 尾瀬地域のPidoniaはミズキやオガラバナのような木本類を, 奥鬼怒地域のPidoniaはオニシモツケ, シラネセンキュウのような草本類を主要な訪花植物とする傾向があった.5. 1989年7月30日, 燧ヶ岳の亜高山帯の枯れたオオシラビソの樹皮内から摂食中のP. bouvieriの幼虫が見つかった.6. 1995年7月25日, 鳩待峠付近のダケカンバの生木の樹皮内から, P. chairoの蛹室が見つかった.それらの高さは, 11例中8例が地上1m以内, 3例が1∿2.8mであった.7. 日本海側地域では冬の積雪が樹皮内で生活するPidonia幼虫を乾燥から守っている.8. 尾瀬・奥鬼怒地域のPidonia相は後氷期の森林の移動に伴って, 太平洋側と日本海側からこの地域に分布を拡大したPidoniaによって形成された.

The vertical and horizontal distribution, the flower visiting habits of adults and larval habits of Pidonia were investigated in the Oze-Okukinu range. This range is situated on the boundary between the Pacific Ocean side of Honshu which experiences summer rains and the Japan Sea side of Honshu which experiences snowfall in winter. The species assemblage of Pidonia in this range is discussed with reference to the biological surveys of Pidonia species in various parts of Japan from 1974 and studies of the dynamic vegetational changes since the Late Wurm Glacial period. A total of 24 species were collected on flowers from 27 to 31 July in 1993. Pidonia occurring in the cool-temperate deciduous forests were unevenly distributed on the Pacific Ocean side and the Japan Sea side of Honshu from one another. P. obscurior, P. insuturata, P. semiobscura, P. limbaticollis and P. oyamae occur in the Pacific Ocean side of Honshu, while P. hakusana, P. hayashii, P. miwai and P. takechii occur in restricted areas on the Japan Sea side of Honshu. Geographically allopatric pairs of phylogenetically related species, such as P. insuturata vs. P. hayashii, P. obscurior vs. P. hakusana occur in this range. Pidonia occurring in Oze visited mainly the flowers of arbores such as Cornus controversa and Acer caudatum ukurunduense. Pidonia occurring in Okukinu visited mainly the flowers of herbs such as Filipendula kamtschatica and Angelica polymorpha. Larvae of P. bouvieri fed on the bark of dead Abies mariesii in the subalpine zone of Mt. Hiuchi-ga-take on July 30, 1989. Larvae of P. chairo pupated directly in the bark of living Betula ermani in Hatomachi Pass on July 25, 1995. Eight examples of 11 pupal cells were found within 1 m above the ground and 3 examples were found from 1-2.8 m and below. Deep winter snows protect the larvae of Pidonia living in the bark of trees against dryness in the Japan Sea side of Honshu. The Pidonia fauna in the Oze-Okukinu range is the result of species expantion from the Pacific Ocean side of Honshu and from the Japan Sea side of Honshu, following the geographic movement of forests during the Postglacial Age.