Eacles imperialis imperialis
Updated as per Heppner's Atlas of Neotropical Lepidoptera Checklist: Part 4B, 1996, November 27, 2005
Lemaire's Ceratocampinae, November 28, 2005

Eacles imperialis imperialis
ee-UH-kleesmmim-PEER-ee-al-ihs
(Drury, 1773) Phalaena

Eacles imperialis (male) courtesy of Tony Thomas (copyright)

This site has been created by Bill Oehlke at oehlkew@islandtelecom.com
Comments, suggestions and/or additional information are welcomed by Bill.

TAXONOMY:

Superfamily: Bombycoidea, Latreille, 1802
Family: Saturniidae, Boisduval, [1837] 1834
Subfamily: Ceratocampinae, Harris, 1841
Genus: Eacles, Hübner, [1819]
Species: imperialis, (Drury, 1773)

MIDI MUSIC

"WhatAWonderfulWorld"
copyright C. Odenkirk
MIDI CITY
ON.OFF
<bgsound src="world.mid" LOOP=FOREVER>

DISTRIBUTION:

Eacles imperialis moths (wingspan: males 92-112mm; females: 87-120mm) are found throughout the eastern half of the United States with greater concentrations in Ohio, southern Pennsylvania and New Jersey, and the Virginias. It is also apparently quite common in the southern states from Florida to at least the eastern half of Texas, based on numerous larval images that are submitted from those states.

In Canada there are populations in southern Quebec and Ontario, but in the provinces the species is generally replaced by the smaller subspecies Eacles imperialis pini.

FLIGHT TIMES:

In the northern half of its range the single-brooded adults are on the wing from June to August. In New Jersey imperialis (males and females) usually came in to lights in July. In the South this species flies from April to October, suggesting at least two broods, but the extended flight season may be due to an irregular emergence pattern. Dirk Bayer confirms there are at least two broods in southern Alabama.

Joel Szymczyk writes, August 9, 2008, "Last night I saw a caterpillar in the glare of my merc light in the back yard. It was obviously Eacles imperialis. It was on one of the ornamental junipers which were planted before I moved here. I pretty much hate those trees and have been seriously thinking about chopping them all down. They are fairly infested with "bagworm" moths, and one tree was completely killed this year by them. Anyhow I was very surprised to see this eating juniper because there are so many decent oaks to choose from.

"Not five minutes later, I saw an adult Eacles hanging in one of the junipers. Definitely a female, and it was ovipositing. This has to be one of the most massive moths in the eastern USA. Cecropia certainly has larger wing area, but the body of this imperialis is just huge. I guess I'll keep the trees, but I have to figure out how to get rid of the bagworms."

ECLOSION:

Adults emerge from underground pupae with most eclosions taking place before sunrise.

SCENTING AND MATING


Photo (female) courtesy of Tony Thomas (copyright)

The slightly larger female begins "calling" after midnight by extending a scent gland from her abdomen. Smaller males fly into the wind to pick up the scent and track the stationary female. Males have more purple on the shoulders and on the outer regions of the forewings.

EGGS LARVAE, PUPAE

Eggs are usually deposited singly or in small groups of 2-5 on a number of coniferous and deciduous trees. Incubation lasts from 12 to 14 days and the larvae emerge as solitary feeders. Under natural conditions larvae would leave the food plant at pupation time and burrow underground to pupate.

Larvae will pupate without soil if placed in the dark in a warm place. Covered five gallon buckets, lined with paper toweling, make good pupation chambers.

The next four larval images are all copyrighted and are used with permission only from Tony Thomas. The parent of these larvae was a female from The Great Dismal Swamp on the border of West Virginia and North Carolina.

The first or second instar larva to the left will quickly move away from one to four siblings to become a solitary feeder on oak, maple, pine, sycamore, Sweet gum, or sassafras, the favorite foods of this species.

Larvae still do not consume much in the second and third instars, and they have also been reported to feed upon various cherries, sumacs, birches, willows, and ash trees

Third and fourth instar larvae become heavy feeders but seldom do damage to the many evergreens (softwoods) upon which they also feed: cedar, fir, (larch/juniper), and pine.

The impressive hairs which become prevalent in the last instars are non-urticating. Some larvae of other species have stinging hairs.

In most cases the larvae take the green form shown at the end of this section.

Steven Stone also reports elm, hickory, hornbeam, chestnut, and privet as foodplants for this highly polyphagous species.

The green larval form pictured below is more typical of this species.

Mature larva can be either green or brown or some combination of the two, usually with two yellow scoli on the first thoracic segment, two elongated yellow to orange thoracic scoli on each of the next two thoracic segments and a single elongated one on the final abdominal segment. There are also two rows of much smaller yellow scoli, one on each of the other abdominal segments.

Courtesy of John A. Weidhaas, University of Vermont

The dimorphic wing coloration of this species is especially evident in this gynandromorph which flew in to a black light in Pottersville, New Jersey, in early July of 1962. My father and I got into an argument over whether it was a male or female until he recognized the bisexual nature of the insect and explained what we had captured.

Larval Food Plants

Listed below are the primary and alternate food plants listed in Stephen E. Stone's Foodplants of World Saturniidae and/or on various internet sites. It is hoped that this alphabetical listing followed by the common name of the foodplant will prove useful. The list is not exhaustive. Experimenting with closely related foodplants is worthwhile.

Abies grandis
Acer negundo
Acer pseudoplatanus
Acer rubrum
Acer saccharinum
Acer saccharum
Aesculus hippocastanum......
Alnus serrulata
Betula alba
Betula papyrifera
Betula populifolia
Bursera tomentosa
Carpinus caroliniana
Carya
Castanea dentata
Castanea pumila
Castanea sativa
Cedrus
Chamaecyparis thyoides
Cochlospermum vitifolium.....
Cornus
Crataegus
Diospyros accharinum
Fagus grandifolia
Fagus sylvatica
Gleditsia triacanthos
Gossypium herbaceum
Juglans cinerea
Juniperus communis
Juniperus virginiana
Koelreuteria paniculata.....
Larix laricina
Ligustrum
Lindera benzoin
Liquidambar styraciflua
Myrica cerifera
Ostrya virginiana
Picea
Pinus banksiana
Pinus echinata
Pinus griffithii
Pinus serotina
Pinus strobus
Pinus taeda
Platanus occidentalis....
Platanus orientalis
Prunus serotina
Prunus virginiana
Quercus alba
Quercus coccinea
Quercus laevis
Quercus macrocarpa
Quercus palustris
Quercus rubra
Rhus glabra
Rhus laurina
Rosa
Robinia
Salix
Sambucus canadensis
Sassafras albidum
Taxodium distichum
Tilia americana
Tilia europaea
Tilia heterophylla.....
Tsuga canadensis
Ulmus alata
Ulmus americana
Ulmus procera
Ulmus rubra
Ulmus thomasii
Viburnum dentatum

Grand fir
Box elder/Manitoba maple
Sycamore maple
Red maple
Silver maple
Sugar maple
European horsechestnut
Hazel alder
White birch
White/paper birch
Gray birch
Torchwood
American hornbeam
Hickory
American chestnut
Allegheny chinquapin
Spanish/Sweet chestnut
Cedar
Atlantic white cedar
Rosa amarillo
Dogwood
Hawthorn
Persimmon
American beech
European beech
Honeylocust
Levant cotton
Butternut
Common juniper
Eastern red cedar
varnish tree
Larch/Juniper/Tamarack
Privet
Spicebush
Sweetgum
Southern bayberry/Wax myrtle
American hop hornbeam
Spruce
Jack pine
Shortleaf pine
Himalayan pine
Pond pine
Eastern white pine
Loblolly pine
American plane tree
Oriental sycamore
Wild black cherry
Chokecherry
White oak
Scarlet oak
Turkey oak
Bur oak
PinOak
Northern red oak
Smooth sumac
Laurel sumac
Rose
Honeylocust
Willow
American elderberry
Sassafras
Bald cypress
American basswood
Common lime
White basswood
Eastern hemlock
Winged elm
American elm
English elm
Slippery elm
Rock elm
Southern arrowwood

Return to Eacles Index

Return to Main Index

The pronunciation of scientific names is troublesome for many. The "suggestion" at the top of the page is merely a suggestion. It is based on commonly accepted English pronunciation of Greek names and/or some fairly well accepted "rules" for latinized scientific names.

The suggested pronunciations, on this page and on other pages, are primarily put forward to assist those who hear with internal ears as they read.

There are many collectors from different countries whose intonations and accents would be different.

Some of the early describers/namers chose genus and species names indicating some character of the insect, but more often, they simply chose names from Greek or Roman mythology or history.

Those species names which end in "ensis" indicate a specimen locale, and those which end in "i", pronounced "eye", honour a contempory friend/collector/etc.

I do not know the source of the genus name "Eacles", but it may be a combination of "Ea", the Greek word for gods and goddesses and the Greek suffix "cles", meaning 'glory of'.

The species name "imperialis" is probably for majestic appearance and colouration of this moth.

Visit Eacles imperialis mature larva, The Woodlands, Montgomery County, Texas, November 2, 2009, courtesy of Sophie and Ellie Johnson.