Description: It is a medium-sized nocturnal moth in the family Notodontidae, widely recognized for its larval stage, which forms conspicuous processions and bears urticating hairs that provide effective protection against predators. Adults display gray and brown tones that allow excellent camouflage against tree bark, with subtly marked forewings and a sturdy body adapted to nocturnal activity. The caterpillars are hairy and generally grayish to brown, often with a darker dorsal band. During development, larvae build distinctive silken nests on branches, especially visible in winter, where they gather to retain heat and shelter from harsh weather conditions.

Geographic distribution: Its distribution covers much of the Mediterranean region and neighboring areas of Europe, North Africa, and parts of the Near East. The species occurs from the Iberian Peninsula across southern and central Europe to the Balkans and parts of western Asia. In recent decades, it has expanded toward more northern latitudes, likely influenced by rising temperatures. In several regions, it is considered a forest-interest species because of its potential impact on conifer stands. It occupies a broad altitudinal range, from coastal environments to mountain forests where suitable host trees are present.

Habitat: It is mainly associated with pine forests and other conifer-dominated habitats, including natural woodlands, commercial plantations, and urban parks with ornamental pines. The species favors temperate climates with relatively mild winters that allow larval survival inside communal silk nests. Forest structure, sun exposure, and host availability strongly influence local abundance. It can also thrive in suburban landscapes where planted pines create suitable conditions.

Diet: The larvae are herbivorous, feeding mainly on pine needles from species within the genus Pinus, though other conifers such as cedars may occasionally be used. Feeding occurs collectively, which can intensify defoliation and weaken host trees. Heavy infestations may reduce tree growth and increase vulnerability to secondary pests or diseases. Adults have little or no feeding activity, focusing most of their short lifespan on reproduction.

Behavior: One of the most remarkable features of this species is the behavior of its larvae, which descend from trees in organized head-to-tail processions to reach the ground for pupation. This social movement enhances orientation and may reduce predation risk. Caterpillars are mostly active at night, while during the day they remain grouped inside their silk nests. The urticating hairs released when disturbed can cause irritation in mammals and birds, functioning as both a physical and chemical defense.

Reproduction: Adults generally emerge in summer, when mating and egg laying occur on pine needles. Females deposit egg masses coated with abdominal scales, offering additional protection. After hatching, larvae pass through several instars and progressively develop communal nests. Pupation takes place underground, where individuals remain until metamorphosis is complete. The timing of the life cycle is closely tied to local climatic conditions and seasonal rhythms.

Conservation status: It is not considered globally threatened and is generally classified as Least Concern, due to its wide distribution and adaptability. However, in many countries the species is monitored because of its economic and health implications, as larval hairs may affect forestry activities, recreation, and domestic animals. Population management is commonly implemented in urban and forested areas to reduce potential risks.

Author of this compilation: EcoRegistros – 12/02/2026