228 motor neuron
Silk Degrees: A Tale of Moths and People,
Part Two
By James G. (Spider) Barbour
Recreational domestication of our native moths dates back
to horses and buggies. Several devoted American and
British silk-moth breeders have committed their knowledge
and experience to print. The first popular book devoted to
rearing moths, Caterpillars and Their Moths,was published
in 1902. The authors, two New Englanders named Ida Eliot
and Caroline Soule, gave detailed accounts of raising 43
species of moths, most of them native to the eastern United
States. Among their successes was a cross-pairing with
viable but infertile hybrid offspring between species of two
different genera, the spicebush silk moth (Callosamia
promethea)and the ailanthus silk moth (Samia cynthia).
Intergeneric hybrids are very rare. Even more remarkable,
as mentioned in part one (page 200) in connection with the
French silk promoter Léopold Trouvelot, the ailanthus silk
moth is a native of China. Though others have tried, to this
day this particular feat of old-style genetic engineering has
never been repeated.
Asimilar book appeared 10 years later by the popular
Indiana novelist Gene Stratton Porter. Moths of the Limber-
lostwas a nonfiction companion to her best-known work of
fiction, AGirl of the Limberlost.Illustrated with the author’s
hand-tinted color photographs, this inspired moth tome
launched many a young reader into the throes of moth culti-
vation, so that by the 1940s, standard techniques of silk-
moth culture had been developed and disseminated.
The Amateur Entomologists’ Society, a British organi-
zation, published a compendium of moth-breeding methods
in its sixth volume in 1942, edited by Beowulf Cooper. The
material in this issue of the AES journal was revised and
expanded by W. J. B. Crotch and published as Volume 12, A
Silk Moth Rearer’s Handbook,in 1956.
The first American authors to present these tech-
niques, along with species accounts, were Michael Collins
and Robert Weast in Wild Silk Moths of the United Statesin- Paul Villiard, a New York moth breeder, published
Moths and How to Rear Themin 1969. Therein he lamented
the policy of the U.S. Department of Agriculture to restrict
importation of nonnative moths, and gave fascinating
accounts of his successes and failures with exotic species.
(By mail from less restricted European breeders, he man-
aged to import living material of many Asian, African, and
tropical American moths.) Attempting to rear the fabulous
Madagascar moon moth (Argema mittrei) from a dozen
eggs he obtained from a British breeder, Villiard offered the
caterpillars every plant he could find. Almost all were
rejected, and the caterpillars died, except for two that
thrived on poison ivy.
In 1996 Cornell University Press published the defini-
tive book (to date) on our native Saturniidae. Authored by
Paul Tuskes, James Tuttle, and Michael Collins, The Wild
Silk Moths of North Americapresents everything you never
imagined there was to know about these spectacular
insects, including rearing tips, collecting techniques, eco-
logical data, host plants, range maps, emergence times in
different parts of a species’s geographic range, and much
more.
As odd an obsession as it may seem to some, there are
a number of perfectly understandable reasons for breeding
moths. Those assembling collections of pinned insects can
obtain perfect, unblemished specimens freshly hatched
from the cocoon. Researchers can perform a variety of con-
trolled experiments by raising large numbers of caterpillars,
for example, comparing growth rates on different caterpillar
host plants, testing the effects of artificial photoperiods on
caterpillar growth and the length of time spent in the pupal
stage, or recording levels of predation on caterpillars
placed in the open on different plants or in different envi-
ronmental settings.
There is even some profit in rearing large numbers of
caterpillars—selling the cocoons to collectors or the pupae
to research labs for a variety of projects. A recent example
is the splicing of a gene from cecropia onto the genome of a
potato to impart resistance to fungus. Mostly, though, silk
moths are simply fascinating animals in their life habits,
their amazing transformations, their large size, and their
otherworldly beauty.
Raising moths is not an entirely easy business,
though. Obtaining fertile eggs is simple enough, once one
has collected a few cocoons. Chances are, in a batch of
six or more cocoons, at least one will produce a female.
Fresh males and females may mate overnight in an amply
sized screen cage. Lacking males, a female may be teth-
ered on a string tied around the thorax between the
wings, tied in an open-ended screen cylinder for protec-
tion from predators, and left in a tree or shrub overnight.
Very likely in the morning there will be a male mating with
her, the female having emitted her seductive perfume (a
chemical attractant called a pheromone) during the night.
Unlike butterflies, most of which cannot be induced to lay
eggs on anything but fresh leaves of a specific plant
species, silk moths will lay eggs on anything. Most breed-
ers place a fertilized female in a paper shopping bag
(plastic will not do), and the moth will lay eggs on the
sides of the bag. The bag can be cut into pieces with
eggs firmly attached, and placed on appropriate host