Download Giant Silk Moth species - Loudoun Wildlife Conservancy

Loudoun Wildlife Conservancy
People and Wildlife Living in Harmony
Audubon at Home Wildlife Sanctuary
Sanctuary Species Fact Sheets
Giant Silkmoths
(Family Saturniinae)
First sighting – Date _________________
The moth family Saturniidae includes three subfamilies – our Target Species group is subfamily Saturniinae
and the four species most commonly seen in Northern Virginia: Luna and Polyphemus (shown above) and
Cecropia & Promethea (not shown). Their family name is derived from the Roman God Saturn because of
their impressive size and markings; the common name speaks to their
silk-woven cocoons. The adults and caterpillars are some of the largest
and most spectacular insects in the world. To find these moths in your
yard, with their richly-colored wings and feathered antennae, is a special
experience. The huge larvae, or caterpillars, are equally impressive, with
vibrant green bodies, colored knobs, glowing markings and suction-cup
“feet” called prolegs. As awesome as the adult moths are, the caterpillars
have far more influence and effect on our forest ecosystems. Adult Giant Silkmoths have reduced or absent
mouthparts, do not feed and only live a few weeks, while their caterpillars spend months playing a crucial
part in the forest food web. Although Giant Silkmoths are eaten by bats, flying squirrels, screech owls and
nightjars, the caterpillars are the essential food source. Moth caterpillars (outnumbering their butterfly
cousins by more than 10 to 1) are the single most important food for songbird nestlings. Whatever the
adult birds eat, all young are fed insects, and moth caterpillars form the largest part of this diet. Even
nectar and seed specialists like hummingbirds and grosbeaks feed caterpillars to their young. In addition to
feeding nestlings, moth caterpillars are vital soil engineers; they break leaves into smaller pieces that fall to
the forest floor and their droppings, or frass, are one of the most evenly distributed and available animal
fertilizer in forest soils. Whether you’re talking songbirds or soils, moth caterpillars literally feed the forest.
Clearing of forests, invasive exotic plants and pesticides are threats.
What Giant Silkworm Moths Need
How You Can Help
Food: Adults don’t feed, so providing food sources is
all about what the caterpillars eat. A diverse multilayered deciduous forest that includes native canopy,
understory and shrub species supports the largest
number of giant silkmoth species. These caterpillars
depend on native plant species; landscapes with
exotics support very few caterpillars and consequently
much fewer of the songbirds that feed on them.

Breeding: Males can detect female pheromones from
almost one mile away with highly sensitive, feathered
antennae. After mating, females lay eggs, usually
fewer than 30, on the underside of host species
leaves. Tiny caterpillars hatch and go through several
molts as they grow from munching on their leafy
meals. They winter as pupae in silk and leaf woven
cocoons.
 Do not use bug zappers as they often attract and then kill many
beneficial, harmless insects like make Giant Silkworm Moths
searching for females
 Silkmoth cocoons often fall to the forest floor and become part of
the leaf and branch litter. If you have larval food tree or shrub
species in your landscape designate a few where fallen leaves are
allowed to remain underneath (at least until June) or you may be
raking up and throwing out silkmoth cocoons when you bag the
leaves in the fall.
Shelter: Each forest layer - i.e. a thick litter of leaves,
branches and log litter, and shrubs, understory and
canopy plants layers as well as standing dead trees are
vital for adult, larvae and pupae.

Other: Several species in this sub-family, especially
the Cecropia and Promethea moths have declined in
recent years partly due to the exotic tachinid fly
(compsilura cocinnata) introduced to control the
exotic Gypsy Moth. The insecticides used to control
Gypsy Moths can also kill silkmoth caterpillars.

If your yard is too small for large trees, use Sassafras (Sassafras
albidum), Spicebush (Lindera spp.), or one of the native scrub oak
or willow shrub species.
 The primary large trees that support Giant Silkmoth caterpillers
include:
 White Oak (Quercus alba)
 Mockernut (Carya tomentosa)
 Pignut Hickory (Carya glabra)
 Sweetgum (Liquidambar spp.)
 Wild Black Cherry (Prunus serotina)
 Black Willow (Salix nigra)
Don’t tidy up all the wooded corners of your yard – allow some
leaf litter, fallen branches, and dead trees to remain
 Create brush shelters for overwintering cocoons
Model Habitat
Blue Ridge Center for Environmental Stewardship – www.blueridgecenter.org
Banshee Reeks Nature Preserve - http://www.loudoun.gov/index.aspx?nid=1277 or www.bansheereeks.org
Claude Moore Park - http://www.loudoun.gov/index.aspx?nid=1285
Source: Fact Sheets prepared by/from Audubon Society of Northern Virginia, National Audubon Society and information compiled by the
Loudoun Wildlife Conservancy.
Photos: ASNV http://www.audubonva.org/images/pdfs/silkmoth.pdf