common name: cecropia moth, cecropia silkmoth, robin moth
scientific name: Hyalophora cecropia Linnaeus (Insecta: Lepidoptera: Saturniidae: Saturniinae: Attacini)

Introduction - Synonymy - Distribution - Description and Life Cycle - Hosts - Economic Importance - Selected References

Introduction

The cecropia moth, Hyalophora cecropia Linnaeus, is among the most spectacular of the North American Lepidoptera. It is a member of the Saturniidae, a family of moths prized by collectors and nature lovers alike for their large size and extremely showy appearance.

Adults are occasionally seen attracted to lights during spring and early summer, a common habit of many moths. It is unclear exactly why these insects visit lights, although a number of theories exist. One such theory posits that artificial lights interfere with the moths' internal navigational equipment. Moths, and indeed many other night-flying insects, use light from the moon to find their way in the dark of night. Since the moon is effectively at optical infinity, its distant rays enter the moth's eye in parallel, making it an extremely useful navigational tool. A moth is confused as it approaches an artificial point source of light, such as a street lamp, and may often fly in circles in a constant attempt to maintain a direct flight path.

Synonymy

Hyalophora Duncan, 1841
Samia. - auct. (not Hübner, [1819])
Platyysamia Grote, 1865

cecropia (Linnaeus, 1758)
diana (Castiglioni, 1790)
macula (Reiff, 1911)
uhlerii (Polacek, 1928)
obscura (Sageder, 1933)
albofasciata (Sageder, 1933)

(from Heppner 2003)

Distribution

The range of Hyalophora cecropia is from Nova Scotia in eastern Canada and Maine south to Florida, and west to the Canadian and U.S. Rocky Mountains.

Description and Life Cycle

Eggs: The large and mottled reddish/brown eggs are are laid by the female on both sides of the host leaf in small groups.

adult laying eggs

eggs

Larvae: There are typically five larval instars, each lasting approximately one week. First instar larvae are black and feed gregariously.

first instar larva emergence

first instar larvae

Second instar larvae are variable from dark yellow to yellow, and also feed gregariously.

second instar larvae

Third, fourth, and fifth instar larvae are similar in their exuberant appearance. The body is very large, with fifth instar larvae reaching up to 4.5 inches in length. Color is bright green or sea green with prominent dorsal protuberances, all with distal black spines. Thoracic protuberances are orange to red, abdominal protuberances are yellow, and side protuberances are pale blue. The larvae of the Columbia Silkmoth (H. columbia) are very similar, but have red thoracic protuberances, yellow-pink abdominal protuberances, and side protuberances which are more white than blue with black bases.

third instar larva

fourth instar larva

fifth instar larva

Pupae: The pupae are large, dark brown, and encased within a silk cocoon that is attached lengthwise along a stem or branch of the host plant or nearby plant.

cocoon

pupa

Adults: Size is variable but usually quite large, with a wingspan approaching up to 6 inches. Wings are brownish with red near the base of the forewing. Crescent-shaped spots of red with whitish center are obvious on all wings, but are larger on the hindwings. All wings have whitish coloration followed by reddish bands of shading beyond the postmedial line that runs longitudinally down the center of all four wings. The body is hairy, with reddish coloring anteriorly, and fading to reddish/whitish. The abdomen has alternating bands of red and white.

newly emerged adult

adults

For an excellent photographic account of the H. cecropia life cycle, see Hyalophora cecropia: Changes of Color and Contrast (Britton 2009).

Hosts

Plant families and species:
(from Heppner 2003)

Economic Importance

While H. cecropia larvae are large and feed on a wide range of host plants, this species is not considered a serious pest in any parts of its range.

Some populations of H. cecropia may be in decline due to a number of factors, including nontarget effects of introduced biological control agents. Boettner et al. (2000) suggested that the generalist parasitoid fly Compsilura concinnata (Diptera: Tachinidae) may be responsible for such declines in the northeastern U.S.

Due to its size and hardiness, H. cecropia has been used extensively in physiological and biochemical research. Carroll Williams conducted pioneering work on juvenile hormone and its role in molting and metamorphosis using this species.

Owing to its impressive size and appearance, H. cecropia has become a favorite of collectors and amateur Lepidopterists. Eggs and pupae are commercially available, and a small livestock industry has developed around this and other related species.

Selected References

Author: Geoffrey R. Gallice, University of Florida
Photographs: David Britton
Project Coordinator: Thomas R. Fasulo, University of Florida
Publication Number: EENY-478
Publication Date: July 2010
Copyright 2010 University of Florida

Featured Creatures
Department of Entomology and Nematology
Division of Plant Industry
Electronic Data Information Source