旭硝子財団助成研究成果報告2020

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56中村　剛之豪雪地帯の雪の下で活動する昆虫群集の解明 73Takeyuki NAKAMURA溝上　展也74Nobuya MIZOUE（2017採択）Investigation of insect communities active under the snow in areas with heavy snowfall(Project 2017)ミャンマーの伝統的林業生態系におけるアジアゾウとの共生の実態と課題 （2017採択）Situation and challenges on coexistence with Asian elephant in traditional forestry ecosysytems of Myanmar(Project 2017)旭硝子財団　助成研究成果報告（2020）Alien species that are translocated among regions within a country have received little attention, compared to those translocated among countries. In this study, we investigated the impacts of an alien toad (Bufo japonicus formosus), which was translocated from Honshu to Hokkaido, on novel amphibian predators in the invaded area, Hokkaido. Larvae of Hokkaido Brown frog (Rana pirica) and Hokkaido salamander (Hynobius retardatus) can die by consuming the alien toad hatchlings due to toxicity of the toad (i.e., Bufotoxin). Our experiments and field survey revealed that the impacts of the toad are much stronger to native frogs than native salaman-ders. In particular, we found the alien toads frequently cause mass mortality of the native frog tadpoles. An-other experiment in laboratory showed original amphibian predators (Rana ornativentris) and (Hynobius ni-grescens) for B. j. formosus toad in Honshu has highly tolerant to the toad toxin. This result allows us to expect that Hokkaido Brown frog and Hokkaido salamander evolve to develop toxin tolerance in the future. Howev-er, our experiment also showed the evolutionary potential of Hokkaido brown frog to develop toxin tolerance is quite low. Hence, it is necessary to pay attention to the impact of alien toads on the vulnerable native frogs.厚い積雪と地面との間のsubnivean zoneと呼ばれる空間で冬の間も冬眠をせず，活動を続ける昆虫が知られている．世界有数の豪雪地帯として知られる日本列島の日本海側の地域では，この環境に適応した特殊な昆虫群集が形成されていると考えられるものの，これまで調査が行われていなかった．北海道，本州各地の大学演習林などでトラップを設置し，豪雪地帯の雪の下で活動する昆虫の多様性を調査した．その結果，翅が退化した双翅目昆虫やハネカクシ科の甲虫類などが多数確認された．こうした昆虫，特にハネカクシ類のいくつかの種はいずれの地域でも複数のトラップで高頻度に捕獲され，雪の下の昆虫群集の主要な構成メンバーとなっていると考えられる．Some insects are known not to hibernate during winter, but to stay active in the small space between heavy snow cover and ground surface, which is called “subnivean zone”. The Sea of Japan side of Japanese Archi-pelago is one of the areas with heaviest snowfalls in the world. It is supposed that peculiar insects have evolved adapting subnivean environments in these areas, however, faunal investigation of subnivean insects had never been conducted in Japan so far. Using pitfall traps at various experimental forests in Hokkaido and Honshu, Japan, I investigated faunae of subnivean insects. As results, some flightless flies (Diptera) with re-duced wings, and some species of staphylinid beetles were captured in large number. It is conceivable that these insects, especially some staphylinids, are the major components of subnivean insect fauna, as they were captured frequently in traps in different investigation sites.本研究では，ミャンマーで160年以上前から集材作業に利用されているアジアゾウの利用の実態や生活・行動様式を明らかにした．ゾウによる集材作業では残存木を避けながら丸太を運搬するため，熱帯林業で問題視されている重機による集材時の残存木への損傷や土壌攪乱は大きくないことがわかり，ゾウを利用することによって他国よりも低インパクトな林業が実現できていることが分かった．林業利用され