Hidemori YAZAKI’s Nature Diary

A Marbled fritillary (Brenthis daphne) in the highlands (I think). It closely resembles the Lesser marbled fritillary (B. ino) of the same genus, and I am not quite confident in my identification. They have a delicate, graceful air, far smaller than the butterflies in Argynnini that are often encountered on the plains. Whilst experiencing the bountiful natural environment of Shinshu, where we can encounter many of these mountain-dwelling butterflies—whose numbers are in decline—and appreciating the efforts of those who work to protect them.

高原のヒョウモンチョウ （だと思う）。 同属のコヒョウモンと酷似し、同定にあまり自信はない。平地の大型ヒョウモン類よりはるかに小さい楚々とした風情。 減少傾向の山地性の蝶に多く出会える信州の自然の懐の深さと、それを守る人々の努力に触れつつ。

Zophoessa callipteris visiting Boneset flowers. A butterfly typical of mountainous forests. Research has experimentally verified the possibility that the small, eye-like markings on the underside of the wings function as a "decoy" to deter visual predators, such as birds, under conditions where ultraviolet light predominates (Olofsson et al. 2010).

ヒヨドリバナの仲間に訪花する、ヒメキマダラヒカゲ。山地の森を代表する蝶。 こうした翅の裏側に並ぶ小さい眼状紋は、鳥などの視覚的捕食者への「おとり」として、紫外線が優占する条件下で機能する可能性を検証した研究がある (Olofsson et al. 2010)。

A Flower swift (Zinaida pellucida) is feeding on nectar from the flowers of what I believe to be Ligularia dentata. How marvellous are the fringe hairs edging its wings! Although this butterfly was once widely found throughout Japan, its population is said to be in sharp decline. Fortunately, on this occasion, we were able to observe many individuals exhibiting vigorous activity.

高原のオオチャバネセセリが、マルバダケブキ（だと思う）の花から吸蜜する。翅をふちどる縁毛の、なんと素晴らしきかな。 かつては全国で広く見られた蝶だが、生息数が急減しているとされる。幸いなことに、今回はたくさんの個体の活発な行動を観察できた。

It was some twenty years ago now, when I was a student at the Faculty of Letters at the University of Tokyo, that I attended a lecture I will never forget. I believe it was an ethics lesson, but it was essentially a structured course in which the lecturer would collect students’ comments on the lecture content, spend the entire following week's session responding to them, and then the students would offer their own replies. From our rather naive comments as students, the lecturer would unfailingly unfold a world of insights that was both incisive and rich. It was a blissful half-year, during which I was simply overwhelmed and utterly captivated by that marvellous experience—as if we were peering up close into the mind of a ‘philosopher’ whilst journeying through the world of ideas together in real time.

All my lectures and exams for this term have come to an end today. Although this was my first term in this post and there were times when I was feeling my way, it has also been a fulfilling period during which I have reaffirmed just how much I enjoy teaching at university. In every lecture, I made a conscious effort to prioritise interaction with the students, precisely because I still cannot forget the excitement of that particular lesson. Whilst I am nowhere near as capable as that lecturer, as someone whose profession is research in the biological sciences, I wanted to help students on the liberal arts programme gain a tangible sense of how research tackles the complex subject of living organisms. Therefore, I set aside a considerable amount of time for responding to comments and cherished the opportunity to reflect on these topics together with the students. Fortunately, in every lecture, I received a great deal of positive feedback from the students regarding these Q&A sessions, which gave me great pleasure; it was both a joy and a delight to witness the depth of their perspectives on the topics under discussion gradually increasing. I hope to continue exploring effective ways to convey the significance and attractiveness of basic research.

The photograph shows the Fringed pink (Dianthus superbus) in a highland.

もう20年も前のこと、私が東大文学部の学生だった頃、忘れられない講義を受けたことがあります。 確か倫理学だったと思いますが、講義内容への学生のコメントを集め、次の週に先生が講義の全ての時間を使ってそれに応答し、また学生がコメントを返す、というスタイルで完結してしまった講義。私たち学生の稚拙なコメントから、先生が毎回どれほど鋭く豊穣な考察の世界を展開してくれたことか。それは「哲学者」という職業人の頭の中を間近に覗き見ながら、リアルタイムで一緒に知の世界を旅していくような驚異的時間に、ただただ圧倒され、夢中にさせられた幸せな半年間でした。

私の今学期の全ての講義・試験は、本日で終了。着任して初めての学期で手探りの部分もありましたが、「大学の講義をするのが私は好きだ」と再認識した充実の日々でもありました。どの講義でも学生とのインタラクションを大切に心がけましたが、それはあの講義の興奮が未だに忘れられないから。あの先生のような力量はとてもありませんが、生命科学の研究を職業とする身として、生物という複雑な対象に研究者たちがどう挑んでいるのか、教養課程の学生が研究という営みを身近に感じる一助となったらと、コメント応答の時間を長くとって、学生のみなさんと共に考える時間を大切にしました。 幸いどの講義でも学生のみなさんから、このコメント応答の時間にたくさんの好評を頂けて私自身とても喜びましたし、学生のコメントの考察がどんどん深まっていくのに接するのは嬉しくも楽しい時間でした。基礎研究の意義と魅力を効果的に伝える手法を、これからも模索していけたらと思います。

写真は、高原のエゾカワラナデシコ。

The highlands in summer are teeming with the Autumn darter (Sympetrum frequens) (smartphone). This species emerges in lowland areas in early summer, migrates to high-altitude regions during the summer, and returns to lowland areas in autumn to breed. According to Futahashi and Hayashi (2004), no regional variation was observed in the population’s genetic structure, and it is presumed that individuals migrate in various directions rather than as a group.

夏の高原は、アキアカネでいっぱい（スマホ）。 本種は初夏に平地で羽化して夏は高標高地に移動し、秋に再び平地に戻って繁殖する。二橋・林 (2004)によると、集団遺伝構造に地域性は認められず、群れ単位でなく個体ごとに様々な方角へ移動すると推測される。

At the weekend, I travelled from Karuizawa—at an altitude of 1,000 metres—further up into the mountains to high-altitude areas exceeding 2,000 metres. I was greeted by Erebia neriene. A typical high-altitude summer butterfly of the Nymphalidae, this species is believed to be a survivor of the Ice Age. In Nagano Prefecture, it is designated as a Prefectural Natural Monument, and collecting specimens is prohibited throughout the prefecture.

週末は、標高1000mの軽井沢からさらに山を上り、2000mを超える高山へ。 出迎えてくれたのは、ベニヒカゲ。夏の高山を代表するジャノメチョウの仲間で、氷河期の生き残りと考えられる種。長野県では県指定天然記念物であり、県内全域で採集が禁止されている。

A species of Reticulated beetle, Tenomerga sp., caught in the light trap. This group is considered to have retained a primitive form even amongst beetles, and is said to have changed little in appearance since the fossils dating back some 200 million years. The texture of the elytra, with their exquisite seal-carving-like pattern reminiscent of Nanbu ironware, is truly magnificent.

ライトトラップにやってきた、ナガヒラタムシの仲間。 甲虫の中でも原始的な形態をとどめたグループで、約2億年前の化石から姿があまり変わっていない、とされる。 南部鉄器のような上質な翅の篆刻の質感が見事。

One morning in the forests of Nagano, I noticed a fascinating sight: droplets of water lined up along the edges of the leaves of a plant I presumed to be Japanese honewort (Cryptotaenia canadensis). This is known as “guttation”—a phenomenon whereby excess water drawn up by the roots seeps out as liquid through the stomata on the edges or tips of the leaves. Apparently, this occurs because transpiration is low and root pressure is increasing at night, which is why the droplets can be observed in the morning.

長野の森の朝、ミツバと思われる植物の葉の縁に水滴が並んでいて面白い。 溢泌と呼ばれ、根から吸い上げた水が余った際に、葉の縁や先端の水孔から液体としてにじみ出る現象だそう。夜は蒸散が弱く根圧が高まるため、朝に水滴として観察できる、というしくみらしい。

Sphragifera sigillata A moth with a distinctive and charming appearance. Whenever this species flies into the light trap during observation sessions, it instantly becomes the centre of attention. Its white-coloured scales also have a distinctive lustre, giving them a glossy appearance.

マルモンシロガ わかりやすくかわいらしい姿の蛾。ライトトラップ観察会で飛んでくると、一躍注目を集める存在。 地色の白い鱗粉も、独特の光沢があってつややかに映える。

Biston regalis The genus Biston, renowned for the “Industrial melanism” seen in the Peppered moth, B. betularia, is usually associated in Japan with notable spring species; thus, the presence of this beautiful species—which is representative of the summer mountains—brings a sense of joy, much like reuniting with a dear old friend at a school reunion. The specific epithet, meaning "Royal", is truly worthy of its noble stature.

ハイイロオオエダシャク 「工業暗化」のオオシモフリエダシャクで高名なBiston属は、日本では春の大物が多いので、夏の山地を代表する美しい本種との出会いは、懐かしい旧友に同窓会で再会するよう。「王者」を意味する種小名は、その高貴な佇まいにふさわしい。

A species of Pyrgotidae, would Adapsila fusca be the correct identification? As its Japanese name suggests, its wasp-like appearance is intriguing; however, it is also fascinating that, in overseas species of the same family, internal parasitism of adult scarab beetles has been recorded, and unusual behaviours—such as laying eggs whilst the host is in flight—have long been reported (e.g. Davis 1919).

デガシラバエ科の一種。フトハチモドキバエでよいでしょうか。 和名通りハチに似た姿が面白いが、海外の同科ではコガネムシ科成虫への内部寄生が記録され、宿主の飛翔時の産卵などの特異な行動が古くから報告されている (e.g. Davis 1919) ことも興味を惹かれる。

How marvellous is the Nun Moth, Lymantria monacha. The dynamic black wave patterns stand out brilliantly against its pure white, three-dimensional dress. Both the Japanese name (nonne, from German) and the specific epithet (monacha, from Latin) are said to mean ‘nun’, though she is certainly a rather avant-garde nun. Moths are truly beautiful.

素晴らしきかな、ノンネマイマイ 立体感のある純白のドレスに、ダイナミックな黒の波模様が映える。 和名 (nonne/ドイツ語) 、種小名 (monacha/ラテン語) は、共に「修道女」の意味だそうだが、なかなかアバンギャルドな修道女ではある。 蛾は、本当に美しい。

Unfortunately, the nighttime nature observation event had to be cancelled due to the heavy rain in Tokyo, so we brought our plans forward and carried out our survey in Nagano. The first to greet me was Amblychia insueta, a magnificent geometrid moth, typical of summer. With wings as splendid as an ink-wash painting adorned with clouds of gold dust, it continues to flutter gracefully around the light trap.

東京の豪雨で残念ながら夜間観察会が中止になったので、予定を早めて長野で調査。 出迎えてくれたのは、チャマダラエダシャク。夏を代表する雄大なシャクガの仲間。水墨画に金粉の雲を描いたような華麗な翅で、ふわりと優雅に灯火の周りを舞い続けている。

Black-faced Bunting (Emberiza personata) Whilst this species is generally regarded as a winter visitor, in Karuizawa highland, it is actually a summer resident. Beautiful mating calls heralding the breeding season, rarely heard in Tokyo, can be heard from all over the neighbourhood in the highland town.

アオジ 冬鳥の印象の強い本種だが、高原の軽井沢ではむしろ夏にやってくる鳥。 東京ではなかなか耳にすることのない繁殖に向けた美しいさえずりの声が、町内の各地から聞こえてくる。

The main actors of Karuizawa’s grasslands: the Chestnut-eared Bunting (Emberiza fucata). All over the grassy areas, the males face upward and sing loudly. The local specimens seem quite wary, so I was delighted to observe their behaviour closely after moving very cautiously.

軽井沢の草原の主役、ホオアカ。 草むらのあちこちで、オスたちは上を向いて高らかにさえずる。 当地の個体はそれなりに警戒心が強い印象で、かなり慎重に動いたところ、じっくりその行動を観察できてよかった。

My work has been selected for the "Photographic Series" category at the Karuizawa Foto Fest 2026. Entitled "Moths Calendar: A Year of Moths in Karuizawa", it features 10 moths that have visited my home in Karuizawa throughout the four seasons. Through the photographs, I would be delighted to convey the profound fascination of nocturnal nature and serve as a gateway to the marvellous world of insects.

My photograph is currently on display outdoors at Hotel Kajiima no Mori in Karuizawa until 21 June, alongside the works of other prize-winners and selected artists in the group photography category, and is also available to view on the Karuizawa Foto Fest website.

軽井沢フォトフェスト2026「組写真部門」で入選しました。 『Moths Calendar 〜軽井沢の蛾の一年〜』と題して、軽井沢の自宅にやってきた春夏秋冬の蛾を集めました。 写真を通じて、夜の自然の奥深い魅力を伝えることができたら、そして昆虫の驚くべき世界に触れるきっかけになれば、嬉しいです。

写真は、軽井沢のホテル鹿島ノ森で6月21日(日)まで、他の組写真部門の入賞者・入選者の作品とともに野外展示されているほか、フォトフェストのHPでも公開されています。

An Oriental Reed Warbler (Acrocephalus orientalis) singing on a power line near a reed bed. Its imposing form somehow reminds me of a dinosaur (though I suppose that makes sense, since it’s a descendant).

芦原の近くの電線の上でさえずっていたオオヨシキリ。 そのいかつさには、どことなく恐竜を思い出す（子孫だからそりゃあそうなんだけれど）。