Automeris

Hübner, 1819

Eyed Silkmoths, Io Moths

Species Guides

7

Automeris is a large of silkmoths (Saturniidae: Hemileucinae) comprising approximately 145 described distributed from eastern North America to Peru. exhibit through leaf-mimicking forewings, while concealed hindwings bear conspicuous eyespots used in startle displays against . Larvae possess venom-bearing urticating spines that cause painful stings to humans and other animals. The genus is , with the genera Leucanella and Pseudautomeris nested within it.

Automeris cecrops by (c) Jeremiah Degenhardt, some rights reserved (CC BY), uploaded by Jeremiah Degenhardt. Used under a CC-BY license.Automeris cecrops by (c) Adriana Nelly Correa Sandoval, some rights reserved (CC BY), uploaded by Adriana Nelly Correa Sandoval. Used under a CC-BY license.Automeris iris by no rights reserved, uploaded by Andreas Manz. Used under a CC0 license.

Pronunciation

How to pronounce Automeris: //ɔːtəˈmɪərɪs//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

distinguished from other Saturniidae by combination of leaf-mimicking forewings and large hidden hindwing eyespots; from superficially similar Sphingidae by broader wings and less streamlined body. Larvae identified by presence of urticating spines (shared with other Hemileucinae but distinct from spineless Saturniinae); -level identification requires examination of spine arrangement, color pattern, and plant association. Distinguished from Lonomia (another stinging hemileucine ) by larval coloration and spine .

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Habitat

Tropical and subtropical forests, including rainforest, cloud forest, and secondary growth. Some occur in agricultural landscapes where plants are cultivated. often found resting on tree trunks, branches, or ground litter during daylight hours.

Distribution

Eastern North America (United States) through Mexico, Central America, and South America to Peru. Highest in Neotropical regions. Specific distribution varies by : Automeris io ranges across eastern North America; Automeris metzli occurs from Mexico to Ecuador and Trinidad; Automeris liberia in Brazilian Amazon; Automeris zozine in Panama and Mexico.

Seasonality

activity patterns vary by and latitude. In temperate regions (e.g., Automeris io), adults fly primarily in late spring and summer. In tropical regions, multiple occur with adults present year-round, peaking during wet seasons. Larvae observed during growing seasons of plants.

Diet

Larvae are folivorous, feeding on leaves of diverse plants including: oak (Quercus), Erythrina, Cajanus cajan (pigeon pea), Elaeis guineensis (oil palm), Schizolobium parahyba, Rubus fruticosus, Macadamia integrifolia, and coconut. have reduced, non-functional mouthparts and do not feed.

Host Associations

  • Cajanus cajan - larval food plantagricultural in Panama
  • Elaeis guineensis - larval food plantoil palm in Brazil
  • Quercus - larval food plantnatural for multiple
  • Erythrina - larval food plantincluding E. speciosa
  • Schizolobium parahyba - larval food plantnatural for A. jucunda in Colombia
  • Rubus fruticosus - larval food plantlaboratory for A. jucunda
  • Macadamia integrifolia - larval food plantcloud forest for A. zozine in Mexico
  • Cocos nucifera - larval food plantcoconut, less common

Life Cycle

Holometabolous. stage duration varies by temperature and . Larval development includes 5-6 instars; duration ranges from six weeks on optimal natural to over eight weeks on suboptimal replacement hosts. Larvae may be solitary or gregarious. occurs in silken cocoon, with emerging after variable period depending on environmental cues. Multiple per year in tropics; typically or in temperate regions.

Behavior

are , resting cryptically during day with forewings covering hindwings. When disturbed, adults perform startle display: forewings are rapidly raised to expose hindwing eyespots while simultaneously wing-futtering and body-thrashing. This visual defense is accompanied by regurgitation in some . Larvae are active feeders; when handled, urticating spines break and release venom causing immediate burning pain, itching, and localized hyperthermia lasting hours. Behavioral sequences show non-random organization with predictable transitions between defensive and routine activities.

Ecological Role

Larvae function as herbivores, occasionally reaching pest status in agricultural systems (oil palm, pigeon pea, macadamia). serve as prey for birds, bats, and other ; their eyespot displays and larval stinging defenses represent anti- adaptations. to tachinid flies including Belvosia and Leptostylum . declines documented in some regions due to by introduced agents, notably the tachinid fly Compsilura concinnata introduced for gypsy moth control.

Human Relevance

Medical significance: larval stings cause erucism, characterized by burning pain, pruritus, edema, and hyperthermia; severe allergic reactions possible in sensitive individuals. Occupational health hazard for agricultural in pigeon pea and oil palm . Automeris io has declined in northeastern North America due to loss and introduction. Some of interest to silk producers and collectors.

Similar Taxa

  • LeucanellaNested within Automeris phylogenetically; morphologically similar with comparable eyespot displays and larval spines. Formerly treated as distinct .
  • PseudautomerisNested within Automeris phylogenetically; shares hemileucine characteristics including urticating larvae and eyespot-bearing .
  • LonomiaAnother hemileucine with venomous larvae; distinguished by different larval coloration, spine , and more severe envenomation (hemorrhagic effects in some Lonomia ).
  • AntheraeaSaturniinae with large eyespots but lacking urticating spines in larvae; lack leaf-mimicking forewings.
  • ActiasSaturniinae with elongated hindwing tails and eyespots but no larval urticating spines; not cryptic at rest.

More Details

Phylogenetic Status

Molecular phylogenetic studies support Automeris as , with the most recent common ancestor dating to approximately 21 million years ago. The Leucanella and Pseudautomeris are nested within Automeris, suggesting need for taxonomic revision.

Conservation Concerns

Automeris io has experienced regional extirpation and decline in New England and parts of its North American range, attributed to combination of destruction and non-target effects of introductions, particularly the fly Compsilura concinnata.

Species Diversity

count has increased from 124 described species in 1996 to approximately 145 currently, with ongoing taxonomic work in Central and South America.

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Sources and further reading