Nature of the Daisetsuzan Mountains
Located in central Hokkaido, the Daisetsuzan Mountains were designated as a national park in 1934. The name “Daisetsuzan” collectively refers to a vast region that includes the volcanic massif surrounding the central crater basin (Ohachidaira), the Ishikari Mountain Range formed by folded mountains, the Tokachidake Range with its still-active volcanoes, and the Shikaribetsu Mountains around Lake Shikaribetsu.
In the central Daisetsuzan area, a ropeway and ski lift provide access to Mt. Kurodake, while another ropeway reaches Mt. Asahidake, allowing relatively easy access to the alpine zone. Mountain huts staffed only during the summer season are limited to the Kurodake Stone Hut and the Hakuundake Shelter, which was rebuilt in 2020.
The alpine flower meadows spreading across the lava plateaus above 1,500 meters are said to be the richest and most beautiful in Japan, and these high alpine environments are inhabited by alpine butterflies.
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Alpine Butterflies of Daisetsuzan
Five species of alpine butterflies inhabit the alpine zone of the Daisetsuzan Mountains, the central highlands of Hokkaido: Parnassius eversmanni, Oeneis melissa, Boloria freija, Agriades optilete, and Erebia ligea. These butterflies are adapted to cold climates and are regarded as circumpolar species distributed across regions surrounding the Arctic. Among them, Erebia ligea is also found in the alpine regions of Honshu, whereas the other four species occur in Japan only in Hokkaido. All four are designated as National Natural Monuments of Japan.
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Parnassius eversmanni daisetsuzana (Family Papilionidae)
A member of the swallowtail family (Papilionidae), this butterfly belongs to the Apollo butterfly group, well known from the European Alps. Many species of this group inhabit alpine regions extending from the Himalayas to Central Asia, and approximately 60 species are known worldwide.
This subspecies is distributed in the northern Korean Peninsula, northeastern China, Siberia, and Alaska, USA. In Japan, it occurs only in the Daisetsuzan Mountains and the Tokachidake Range of Hokkaido.
Its larval host plant is Dicentra peregrina, commonly known as komakusa, a member of the poppy family often referred to as the “queen of alpine plants.” The life cycle usually takes two years: during the first year the species overwinters as an egg containing a first-instar larva, while in the second year the larva forms a cocoon and passes the winter as a pupa. Adults emerge from early June of the third calendar year.
Adults visit alpine flowers such as Diapensia lapponica, Loiseleuria procumbens, and Rhododendron aureum for nectar. In recent years, the emergence period has become earlier due to global warming, and adults have largely disappeared by August. On rare occasions, a second generation may emerge in September.
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Oeneis melissa daisetsuzana (Subfamily Satyrinae)
A member of the satyrine subfamily (Satyrinae), this butterfly is also distributed in Siberia and Alaska, USA. In Japan, it occurs in the Daisetsuzan Mountains and the northern Hidaka Range of Hokkaido. Populations from the Hidaka Range tend to be larger and darker in coloration, and are treated as the subspecies ssp. hidakaensis.
The larvae feed on sedges of the family Cyperaceae, including Carex stenantha and Carex curvicollis. The species has a prolonged life cycle: it overwinters as a first- or second-instar larva during the first year, and as a third- to fifth-instar larva during the second year. Some individuals emerge as adults in the third year, while others require an additional year and emerge in the fourth year. Adults begin to appear from mid-June onward.
Adults rarely visit flowers for nectar, although they are occasionally observed feeding on flowers such as Sieversia pentapetala and Dryas octopetala.
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Boloria freija asahidakeana (Family Nymphalidae)
This nymphalid butterfly is widely distributed across northern Eurasia and North America. Both its Japanese name and subspecific name are derived from Mt. Asahidake, the highest peak of the Daisetsuzan Mountains.
The larvae feed mainly on Rhododendron aureum, although they also utilize plants such as Vaccinium vitis-idaea, Empetrum nigrum, and Vaccinium uliginosum. Adults begin emerging around the same season as Parnassius eversmanni daisetsuzana, and may continue to emerge into August in areas where snowmelt is delayed.
The species overwinters as a fourth-instar larva. After resuming activity the following spring, the larvae molt into the fifth instar before pupation and adult emergence. Adults fly rapidly over alpine shrub communities dominated by Rhododendron aureum and visit flowers such as Loiseleuria procumbens and Phyllodoce caerulea for nectar.
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Agliades optilete daisetsuzana (Family Lycaenidae)
A small lycaenid butterfly in which the upper side of the male wings is blue, whereas that of the female is brownish. This species is distributed across northern Eurasia and northern North America.
Unlike the other alpine butterflies of Daisetsuzan, it also occurs in lowland coastal areas of eastern Hokkaido, including Mt. Rausu, Mt. Shari, the Nemuro Peninsula, and the vicinity of Lake Furen. The larvae feed on plants such as Vaccinium uliginosum, Empetrum nigrum, and Vaccinium vitis-idaea. Adults begin emerging from mid-July onward.Adults visit flowers such as Bryanthus gmelinii, Geranium erianthum, and Spiraea betulifolia for nectar.
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Erebia ligea rishirizana (Subfamily Satyrinae)
This satyrine butterfly is distributed across northern Eurasia and Sakhalin, and also occurs in the alpine regions of the mountains of Honshu, Japan. In Hokkaido, it was first discovered on Mt. Rishiri, from which its subspecific name is derived.
Unlike the other alpine butterflies of Daisetsuzan, this species is more characteristic of subalpine zones. At localities such as Sekihoku Pass and Mikuni Pass, it occurs together with Erebia neriene. Adults emerge from early to mid-July, somewhat earlier than Erebia neriene.
The larvae feed on sedges such as Carex stenantha and Carex flavocuspis. The species overwinters as a fourth-instar larva, molts into the fifth instar the following year, and then pupates and emerges as an adult. Adults visit flowers such as Cirsium yezoalpinum , Arnica unalaschcensis, and Picris hieracioides for nectar.
Unlike the other alpine butterflies of Daisetsuzan, it also occurs in lowland coastal areas of eastern Hokkaido, including Mt. Rausu, Mt. Shari, the Nemuro Peninsula, and the vicinity of Lake Furen.
The larvae feed on plants such as Vaccinium uliginosum, Empetrum nigrum, and Vaccinium vitis-idaea. Adults begin emerging from mid-July onward.Adults visit flowers such as Bryanthus gmelinii, Geranium erianthum, and Spiraea betulifolia for nectar.
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