Imperial moth

Status

"Eacles imperialis" is one of a few saturniid species in a regional decline throughout the northeastern US, with some New England states lacking records for many decades. A colony on Martha's Vineyard, Massachusetts has been the subject of scientific and local political activity, especially concerning preservation of sensitive frost-bottom oak/pine habitat. Reasons for decline are unclear, as are the true northern limits of the nominate's range, due to possible confusion with subspecies "E. i. pini" in existing records. "E. imperialis" is certainly a common species of middle-atlantic states, Appalachia, the Ohio Valley, and Deep South regions, and is associated with forest, rural and suburban habitat. It is possible that to the north, "E. imperialis" requires specific habitat and that the increasing fragmentation of niches such as coastal or montane pine barrens is a factor.

Behavior

There is only one brood a year.

Reproduction

The caterpillars tend to wander before settling down to eat. The first instar generally lasts only a few days. At the end of each instar, a small amount of silk is spun on the major vein of a leaf. The caterpillar then latches onto the silk with its anal claspers and prolegs and begins to molt. It first becomes dormant and undergoes apolysis, then after an additional day or so, undergoes ecdysis. The caterpillar emerges from its old exoskeleton, puffs up, and hardens as it enters the next instar. This species will sometimes eat the old exoskeleton for protein nutrition. Similar to many other Saturniidae caterpillars, the imperial moth has five instars. By the third instar, variation between caterpillars can be observed. This species is known to have two basic color forms, a black-orange form and a green-yellow form. There is also variation within those two forms on the head, spines, body, and feet. At the end of the fifth instar, the caterpillar will leave the tree and travel along the ground in search of a soft soil patch in which to pupate.

Food

Larvae feed on a variety of host plants including:
⤷ "Quercus"
⤷ "Acer"
⤷ "Liquidambar styraciflua"
⤷ "Sassafras albidum"
⤷ "Pinus"