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ECOLOGY ▪ EDUCATION ▪ ADVOCACY

Adult male — Scott County (Ronda Byers)
Adult male (underside) — Washington County (Suzanna Hendrix)
Adult female — Owen County (Rick Malad)
Mating adults — Tippecanoe County (Ron Needham)
Closeup of adult male antennae — Owen County (Rick Malad)
Closeup of adult female antennae — Tippecanoe County (Chris Joll)
Early instar caterpillars — Johnson County (JoAnne Cummings)
Early instar caterpillar — Pike County (Jeremy Ross)
Caterpillar feeding — Huntington County (Andrea Schwartz)
Last instar caterpillar — Monroe County (Martin Willimas)
Pupa — Hamilton County (Amanda Smith)
Female laying eggs — Brown County (Rangel McThurman)
Eggs — Brown County (Rangel McThurman)
American Flag Flag of Indiana An Indiana Native

Eacles imperialis imperialis — Imperial Moth

(Drury, 1773)

imperialis Subspecies imperialis Species Eacles Genus Ceratocampinae Subfamily Family Saturniidae Bombycoidea Superfamily Order Lepidoptera Insecta Class Hexapoda Subphylum Phylum Arthropoda Kingdom Animalia
imperialis Subspecies imperialis Species Eacles Genus Ceratocampinae Subfamily Family Saturniidae Bombycoidea Superfamily Order Lepidoptera Insecta Class Hexapoda Subphylum Phylum Arthropoda Kingdom Animalia

Hodges# 7704

Etymology

Eacles: Unknown.

Imperialis: Latin for “of the empire.”

Pronunciation

ee-uh-kleez im-pihr-ee-al-iss im-pihr-ee-al-iss

Other Common Names

Great-plane tree moth. Hoosier author Gene Stratton Porter referred to the species as the “yellow emperor moth.”

Adult male — Scott County (Ronda Byers)
Adult male (underside) — Washington County (Suzanna Hendrix)
Adult female — Owen County (Rick Malad)
Mating adults — Tippecanoe County (Ron Needham)
Closeup of adult male antennae — Owen County (Rick Malad)
Early instar caterpillars — Johnson County (JoAnne Cummings)
Early instar caterpillar — Pike County (Jeremy Ross)
Caterpillar feeding — Huntington County (Andrea Schwartz)
Last instar caterpillar — Monroe County (Martin Willimas)
Pupa — Hamilton County (Amanda Smith)
Female laying eggs — Brown County (Rangel McThurman)
Eggs — Brown County (Rangel McThurman)

Adult Size and Description

  • Wingspan: 80–170 mm (3.1–6.7 in)
  • Coloration and Patterning:
    • Both sets of wings pale to vibrant yellow with brick-red to plum to rust-brown basal patches, postmedial lines, and scattered dots on upper surfaces.
    • Females: Mostly yellow aside from red basal patches and postmedial lines
    • Extensive red areas. Particularly in basal areas and often from postmedial lines to margins on upper surfaces of both wings.
    • Upper surfaces of both wings of both genders with gray discal spots bordered in red
  • Sexual Dimorphism:
    • Females larger than males and with considerably less red coloration
    • Antennae quadripectinate on males and filiform on females
    • Males have a purplish patch on the end of the underside of their abdomen. Females lack this marking.
  • Defense Mechanisms:
    • Crypsis — Resembles leaf litter.

Range

This map illustrates documented North American records of Eacles imperialis imperialis as of 13 February 2021. The data used likely consists of combined records with the subspecies E. imperialis pini.

species present icon Documented record(s)

Conservation Status — NatureServe Rankings

ConservationBaseMap Indiana Status National Status Global Status NR 5 5

 Secure 5: Secure not ranked NR: Not ranked


Historical References

Included within Dru Drury’s three-volume Illustrations of Natural History, Wherein are Exhibited Upwards of 240 Figures of Exotic Insects, published between 1770 and 1787, was a plate featuring male and female imperial moths.


Floral Associates

Eacles imperialis imperialis caterpillars are the largest in Indiana. Polyphagous, they eat the foliage of several families and genera of native trees, including their namesake hickories (Carya spp.) Adults lack a digestive system, do not eat, and exist solely for reproduction.

Known Larval Food Sources in Indiana
Family Taxonomic Name Common Name
Order: Ericales
EbenaceaeDiospyros virginianapersimmon
Order: Fabales
FabaceaeGleditsia spp.water and honey locusts
Order: Fagales
BetulaceaeAlnus spp.alders
Betula spp.birches
FagaceaeCastanea dentataAmerican chestnut
Fagus grandifoliaAmerican beech
Quercus spp.oaks
JuglandaceaeCarya spp.hickories
Juglans spp.black walnut and butternut
Order: Gentianales
RubiaceaeCephalanthus occidentalisbuttonbush
Order: Hamamelidales
PlatanaceaePlatanus occidentalisAmerican sycamore
Order: Laurales
LauraceaeSassafras albidumsassafras
Order: Malvales
TiliaceaeTilia americanaAmerican basswood
Order: Pinales
CupressaceaeJuniperus spp.junipers
PinaceaeLarix spp.larch, aka tamarack
Picea spp.spruce
Pinuspines
Tsuga canadensiseastern hemlock
Order: Poales
PoaceaeZea mayscorn
Order: Rosales
MoraceaeMorus spp. mulberries
RosaceaePrunus spp.cherries
UlmaceaeUlmus spp.elms
Order: Salicales
SalicaceaePopulus spp.poplars
Salix spp.willows
Order: Sapindales
AceraceaeAcer spp.maples
AnacardiaceaeRhus spp.sumacs
HippocastanaceaeAesculus spp.buckeyes
Order: Saxifragales
AltingiaceaeLiquidambar styracifluaAmerican sweetgum

Imperial Moth (Eacles imperialis imperialis) in Indiana

The map, graph(s), and data below represent the Indiana sightings of Eacles imperialis imperialis as of 14 November 2024, confirmed through photographic evidence by individuals who contributed to the Great American IN Nature Lepidoptera Project (GAIN LP).

Occurrences by County

Counties recorded: 65 of 92

Top counties/#of records:
Washington: 96
Brown: 38
Monroe: 35
Scott: 33
Owen: 24
Hamilton: 22
Morgan: 18

species present icon GAIN LP documented in county

Sightings by Month

Total Sightings by Year

Sightings by Gender

Image Gallery

The images and records below were all submitted by individuals through the Great American Indiana Nature Lepidoptera Project (GAIN LP).