Hylesia

Adult females possess urticating setae on the abdomen that can penetrate human skin, distinguishing them from many other saturniid genera. Specific visual identification characters for the genus as a whole are not documented in available sources; species-level identification requires examination of genitalia and wing pattern details.

Hylesia species inhabit tropical and subtropical environments including seasonally dry tropical forests, coastal regions, and agricultural areas. In French Guiana, outbreak-prone sites are associated with low tree densities and pronounced seasonal variation between dry and rainy periods, contrasting with stable inland rainforest ecosystems where outbreaks are rare.

South and Central America: documented in Brazil (Minas Gerais, Rio de Janeiro, São Paulo, Paraná, Santa Catarina, Rio Grande do Sul), Venezuela (Anzoátegui, Sucre, Monagas), French Guiana, Colombia, Argentina, and Paraguay.

Adult emergence is synchronized with rainy seasons. Hylesia metabus shows peak activity July through September during the May–November rainy season in Venezuela. Seasonal outbreaks correlate with climate patterns, particularly pronounced dry-rainy season transitions.

Holometabolous development with egg, larval, pupal, and adult stages. Hylesia metapyrrha completes development in approximately 191 days under laboratory conditions: egg incubation 52 days, seven larval instars over 74.59 days, pre-pupa 8.82 days, pupa 50.56 days, and adult stage 5.50 days. Female pupae are significantly larger and longer-developing than males. Hylesia metabus exhibits multivoltine cycles with overlapping generations and pupation in soil.

Larvae of H. metapyrrha display gregarious habits, dispersing at pre-pupa formation. Adult females of multiple species exhibit strong positive phototaxis, aggregating around artificial light sources. Females release clouds of urticating abdominal setae that become airborne and cause dermatological and respiratory symptoms in humans. Mass emergence events lead to high-density aggregations.

Major public health concern due to lepidopterism—urticating setae from adult females cause pruritic dermatitis, papular urticaria, and respiratory symptoms. Epidemic outbreaks documented in Argentina, Brazil, Venezuela, Colombia, and French Guiana. Affected populations include oil workers, coastal residents, and agricultural communities. Treatment involves antihistamines and topical steroids; prevention focuses on avoiding light-attracted aggregations and using protective barriers.

• Other Hemileucinae generaHemileucinae includes other urticating moths, but Hylesia is distinguished by adult female setae causing lepidopterism rather than larval urtication alone.

• urticating
• lepidopterism
• public health
• seasonal outbreaks
• phototaxis

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• What’s Eating You? Black Butterfly (Hylesia nigricans)
• Biological aspects of Hylesia metapyrrha (Lepidoptera; Saturniidae; Hemileucinae), in laboratory
• Dermatitis Caused by Moths of Hylesia Genus (Lepidoptera, Saturniidae) in Northeastern States of Venezuela: I. Bioecology of Hylesia metabus Cramer. Clinical Features of Lepidopterism Determined by This Species
• Dermatitis Caused by Moths of Hylesia Genus (Lepidoptera, Saturniidae) in Northeastern States of Venezuela: I. Bioecology of Hylesia metabus Cramer. Clinical Features of Lepidopterism Determined by This Species
• Dermatitis Caused by Moths of Hylesia Genus (Lepidoptera, Saturniidae) in Northeastern States of Venezuela: I. Bioecology of Hylesia metabus Cramer. Clinical Features of Lepidopterism Determined by This Species
• Parasitoides larva-pupa de Hylesia metabus Cramer (Lepidoptera: Saturniidae) en la región nororiental de Venezuela: un caso de control Biológico Natural
• Influence of habitat and climate on the spatial distribution of outbreaks of the Hylesia metabus moth, responsible for Lepidopterism, in coastal French Guiana
• Transposable element accumulation drives genome size increase in Hylesia metabus (Lepidoptera: Saturniidae), an urticating moth species from South America.