A blue underwing butterfly, a rare species listed in the regional Red Data Book, has been spotted at the Aerodrom cordon of the Kronotsky Nature Reserve in Kamchatka.
The population of the blue underwing in Kamchatka is significantly lower than in the European part of Russia or Siberia. Because of this localized scarcity, every new sighting of the rare insect holds substantial entomological interest.
As a large butterfly, the blue underwing can cover considerable distances under favorable conditions – indicating that its gradual spread across the peninsula is highly likely. The eggs produced by this species are exceptionally winter-hardy and can withstand freezing temperatures down to minus 30 degrees Celsius. During their larval stage, the caterpillars feed exclusively on various trees and shrubs rather than herbaceous plants.
The butterfly possesses a wingspan of up to 10 centimeters and derives its common name from its distinctive coloration. While at rest, the insect conceals its body using dull, camouflaged forewings. At the slightest sign of danger, it rapidly opens its wings to reveal hindwings marked with a striking bright blue stripe. This sudden flash of color serves as a defense mechanism to startle and deter potential predators – including birds and other insectivorous animals.
The blue underwing was first recorded in Kamchatka in 2001 near the village of Yagodny. Subsequent sightings occurred in 2012 when a specimen was photographed at the Travyanoy cordon in the South Kamchatka Sanctuary. Two years later, the species was observed in the Valley of Geysers and the Uzon volcano caldera. These repeated discoveries have conclusively established that the Kamchatka Peninsula is an active part of the habitat for this rare butterfly.