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Eudyaria zeta

Eudyaria zeta


Family: Saturniidae
Order: Lepidoptera
Class: Insecta
Phylum / Division: Arthropoda
Kingdom: Animalia

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Description


Represents a medium-sized nocturnal lepidopteran featuring a wingspan that typically ranges between 35 and 48 millimeters. Marked sexual dimorphism is present, particularly noticeable in the antennal structure, which is strongly bipectinate in males to detect female pheromones and simple or slightly serrate in females. The general coloration of the forewings is predominantly grayish-brown or dark beige, patterned with an intricate network of dark transverse lines and lighter markings that resemble geometric or glyph-like shapes, providing outstanding cryptic protection against tree bark. Conversely, the hindwings are substantially lighter, displaying shades that range from dirty white to pale gray, occasionally showing subtle pinkish or yellowish undertones near the wing base. The body is robust, covered with dense, hairy scales of a dark brown color on the thorax and abdomen, with the latter sometimes displaying transverse bands of a contrasting hue.

Geographical distribution: Occurs natively within the Neotropical region of South America. Its presence is widely recorded throughout northern and central Argentina, including provinces such as Misiones, Corrientes, and Buenos Aires. Furthermore, its range extends into the southern and southeastern states of Brazil, such as Rio Grande do Sul, Paraná, and São Paulo, as well as several forested zones within Paraguay and Uruguay.

Habitat: Inhabits primarily forested and transitional ecosystems, demonstrating a close association with the Paranaense rainforest, the Atlantic Forest, and gallery forests that border riparian systems. This species can be found in well-preserved primary forests as well as secondary growth forests and rural forest patches containing native vegetation. It prefers microhabitats characterized by moderate to high humidity levels and temperate to warm temperatures, where the dense canopy offers adequate shade and daytime shelter from potential predators.

Feeding: During its larval or caterpillar stage, this insect is highly phytophagous, exhibiting a clear tendency toward polyphagy by consuming the foliage of various host plants, especially those belonging to the Fabaceae, Solanaceae, and Myrtaceae families. In contrast, upon reaching adulthood, the imago possesses a highly reduced or atrophied proboscis, making feeding impossible. Consequently, adults rely exclusively on lipid and protein reserves accumulated during their larval development to sustain all vital metabolic functions during their brief lifespan.

Behavior: Displays strictly nocturnal and crepuscular activity patterns. During daylight hours, it remains completely motionless in a resting posture on tree trunks or beneath leaves, relying on its cryptic coloration to avoid detection by birds and other insectivores. Males become highly active during the dark hours and are strongly attracted to artificial light sources, a behavioral trait typical of many erebid moths that facilitates scientific monitoring and population surveys.

Reproduction: The reproductive cycle begins when virgin females release highly volatile chemical sex pheromones from specialized abdominal glands to attract prospective mates. Following nocturnal copulation, the female deposits her eggs in small, compact clusters on the underside of host plant leaves. After a brief incubation period, tiny caterpillars hatch and progress through several larval instars, feeding voraciously on foliage. Upon reaching maturity, the caterpillar spins a loose silk cocoon integrated with its own larval hairs, typically placed within the leaf litter on the forest floor or inside bark crevices, where it undergoes metamorphosis into the pupa or chrysalis stage.

Conservation status: Is currently classified as Not Evaluated (NE) by the IUCN Red List. Nevertheless, localized populations face persistent threats due to habitat fragmentation, deforestation of the Atlantic Forest, and the heavy application of broad-spectrum chemical insecticides in agricultural lands adjacent to its native forest remnants.



Compilation and publication: EcoRegistros – 07/09/2026




Geographic distribution


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Species photographs

Last published photographs

Foto
Photography ID: 541643
  Larva

Tandil
Buenos Aires
Argentina
05/19/2021
Fernando Rasmussen
Foto
Photography ID: 541642
  Adult

Tandil
Buenos Aires
Argentina
03/19/2005
Fernando Rasmussen
Foto
Photography ID: 331151
  Larva

Tandil
Buenos Aires
Argentina
08/19/2017
Roberto Battaglia
Foto
Photography ID: 318294
  Adult

Tandil
Buenos Aires
Argentina
02/21/2019
Santiago Juan Torres



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Page 1
Record IDDateExact timeCountryProvince / departmentPlaceFilmedPhotographedRecorded vocalObservedHeardWounded or deadNumber of individualsUser or BibliographyDetail
179307919/05/2021ArgentinaBuenos AiresCerro La Cascada, TandilFernando Rasmussen
88979621/02/2019ArgentinaBuenos AiresVilla del Lago, TandilSantiago Juan Torres
92061319/08/2017ArgentinaBuenos AiresTandilRoberto Battaglia
179307619/03/2005ArgentinaBuenos AiresCerro Ayastuy, TandilFernando Rasmussen
Page 1

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Recommended citation
Please use the following reference when citing this species account.
EcoRegistros. 2026. Eudyaria zeta – Species account. Accessed from www.ecoregistros.org on 24/09/2026.