Saturniidae

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Saturniids

Promethea silkmoth, Callosamia promethea

Scientific classification

Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Lepidoptera
Superfamily:	Bombycoidea
Family:	Saturniidae

Subfamilies

Oxyteninae
Cercophaninae
Arsenurinae
Ceratocampinae
Hemileucinae
Agliinae
Ludiinae
Salassinae
Saturniinae

The Saturniidae, collectively known as saturniids, are among the largest and most spectacular of the Lepidoptera, with an estimated 1,300 to 1,500 different described species existing worldwide (Grimaldi and Engel, 2005). The Saturniidae family includes the giant silkmoths, royal moths, and emperor moths.

Adults are characterized by large size, heavy bodies covered in hair-like scales, lobed wings, reduced mouthparts, and small heads. They lack a frenulum but the hind wings overlap the forewings, producing the same function (Tuskes et al., 1996). These moths are sometimes brightly colored and often have translucent eyespots or windows on their wings. Sexual dimorphism varies by species, but males can always be distinguished by their larger, broader antennae. Most adults possess wingspans between 1 to 6 inches (2.5 to 15 cm), but some tropical species, such as the atlas moth (Attacus atlas), may boast incredible wingspans of up to 12 inches (30 cm).

1 Distribution
2 Life cycle
3 Importance
4 Species
5 References
6 External links

[edit] Distribution

The majority of saturniid species occur in wooded tropical or subtropical regions, with the greatest diversity in the New World Tropics and Mexico (Tuskes et al., 1996), though they are found all over the world. There are approximately one dozen described species living in Europe, one of which, the Emperor Moth, occurs in the British Isles, and 68 described species living in North America, 42 of which reside north of Mexico and Southern California.

[edit] Life cycle

Some saturniids produce more than one brood a year. Spring and summer broods hatch in a matter of weeks; autumn broods enter a state known as diapause and emerge the following spring. How the pupae know when to hatch early or hibernate is not yet fully understood, though research suggests that day length during the larvae's 5th instar plays a major role. Longer days may prompt pupae to develop early, while shorter days result in pupal diapause. The number of broods is flexible, and a single female may produce both fast-developing and slow-developing individuals, or they may produce different numbers of broods in different years or parts of the range (Tuskes et al., 1996). In some species, spring and summer broods look different, with different genes activated by environmental conditions (Actias luna, Callosamia securifera) (Tuskes et al., 1996).

[edit] Eggs

Depending on the moth, a single female may lay up to 200 eggs on a chosen host plant. Others lay singly or in small groups (Scoble, 1995). They are round, slightly flattened, smooth and translucent or whitish.

[edit] Larvae

Saturniid larvae are large (50 to 100 mm in the final instar), stout and cylindrical. Most have tubercules that are often also spiny or hairy. (The other caterpillars in this size range are the Sphingidae, which are seldom hairy and tend to have diagonal stripes on their sides.) Many are cryptic in coloration, with countershading or disruptive coloration to reduce detection, but some are more colourful. Some have stinging hairs (Scoble 1995). Most are solitary feeders, but again, some are gregarious. The Hemileucinae have stinging hairs and are gregarious when young (Tuskes et al., 1996). Most larvae feed on the foliage of trees and shrubs, a few, such as Automeris louisiana and A. patagonensis feed on grasses. They moult at regular intervals, usually four to six times before entering the pupal stage. Prior to pupation, there is a wandering stage, and they may change colour, becoming more cryptic just before this stage (Tuskes et al., 1996).

Brazilian Saturniid larva

Saturnia pyri Giant peacock moth larva

[edit] Pupae

Most larvae spin a silken cocoon in the leaves of a preferred host plant or in leaf litter on the ground, or crevices in rocks and logs. While not closely related to the silkworm (Bombyx mori, Bombycidae), these cocoons can be gathered and used to make silk fabric. However, larvae of the regal moth (Citheronia regalis) and imperial moth (Eacles imperialis) burrow and pupate in a small chamber beneath the soil. This is common in the Ceratocampinae and Hemileucinae. Unlike most silk moths, those that pupate underground do not use much silk in the construction (Tuskes et al., 1996). Once enclosed in the cocoon, pupae undergo metamorphosis.

[edit] Adults

Adult females emerge with a complete set of mature ova and "call" males by emitting pheromones (specific "calling" times vary by species). Males can detect these chemical signals up to a mile away with help from sensitive receptors located on the tips of their featherlike antennae. The males will fly several miles in one night to locate a female and mate with her; females generally will not fly until after they have mated.

Since the mouthparts of adult saturniids are vestigial and digestive tracts are absent and adults subsist on stored lipids acquired during the larval stage. As such, adult behavior is devoted almost entirely to reproduction, but the end result (due to lack of feeding) is a lifespan of a week or less.

[edit] Importance

A few species are important defoliators, including Coloradia pandora on pines, Hemileuca oliviae on range grasses, Anisota senatoria on oaks. Other species provide silk for fabric, such as Samia cynthia and Antheraea pernyi.

[edit] Species

(Note: This list is by no means complete.)

Subfamily Agliinae -- one genus, Aglia
Subfamily Arsenurinae -- 10 Neotropical genera
Subfamily Ceratocampinae -- 27 genera, New World
- Genus Anisota
  - Spiny oakworm moth, Anisota stigma
  - Orangestriped oakworm, Anisota senatoria
- Genus Citheronia
  - Regal moth, Citheronia regalis
- Genus Dryocampa
  - Rosy maple moth, Dryocampa rubicunda
- Genus Eacles
  - Imperial moth, Eacles imperialis
Subfamily Hemileucinae -- 51 genera, New World
- Genus Automeris
  - Io moth, Automeris io
- Genus Coloradia
  - Pandora moth, Coloradia pandora
Subfamily Ludiinae -- 8 genera, African
Subfamily Salassinae -- 1 genus, Salassa Tropical
Subfamily Saturniinae -- 59 genera, global
- Genus Actias
  - Actias artemis
  - Luna moth, Actias luna
  - Malaysian moon moth, Actias maenas
  - Indian moon moth, Actias selene
  - South China moon moth, Actias heterogyna
- Genus Antheraea
  - Polyphemus moth, Antheraea polyphemus
  - Chinese oak silkmoth Antheraea pernyi
- Genus Attacus
  - Atlas moth, Attacus atlas
- Genus Callosamia
  - Promethea silkmoth, Callosamia promethea
- Genus Graellsia
  - Graellsia isabellae
- Genus Hyalophora
  - Ceanothus silkmoth, Hyalophora euryalus
  - Cecropia moth, Hyalophora cecropia
  - Columbia silkmoth, Hyalophora columbia
- Genus Loepa
  - Golden Emperor Loepa katinka
- Genus Opodiphthera
  - Emperor Gum Moth, Opodiphthera eucalypti
- Genus Samia
  - Ailanthus silkmoth, Samia cynthia
- Genus Saturnia (moth)
  - Great peacock moth Saturnia pyri
  - Emperor moth Saturnia pavonia

[edit] References

Burnie, David (2001). Smithsonian: Animal. First American Edition, Oct 2001. DK Publishing Inc., 375 Hudson St. New York, NY 10014.
Mitchell, Robert T (2002). Butterflies and Moths: A Golden Guide From St. Martin's Press. St. Martin's Press, New York.
Scoble, MJ. 1995. The Lepidoptera: Form, Function and Diversity. Second ed. Oxford University Press.
Tuskes, PM, JP Tuttle and MM Collins. 1996. The wild silk moths of North America. Cornell University Press. ISBN 0-8014-3130-1