Citheronia regalis
Encyclopedia
The regal moth also called the royal walnut moth, is a North American moth
in the saturniidae
family. The caterpillars are called hickory horned devils. The adult (Imago
) has a wingspan of 9.5-15.5 cm.
, as are the spectacular larva
and the substantial pupa
.
The life cycle of the moth is typical of the Saturniidae species, and typical of the Ceratocampinae
. It burrows into the ground to pupate in an earthen chamber, rather than spinning a cocoon.
Yellowish eggs, oval and 2 mm in diameter, are laid either singly or in groups of up to four on the upper surface of the host
plant leaves, favoring nut trees such as Juglans and Carya (walnut and hickories). There are regional preferences, with the utilization of sweet gum and persimmon in the south, and sumacs where the others are not available. Larvae are solitary in later stages and rarely occur in numbers large enough to cause defoliation, however an individual larva can strip several branches of their leaves during the ravenous 5th instar
.
The general list of recorded hosts contains hickories (Carya glabra, Carya illinoensis, Carya ovata), Buttonbush
, Filbert, Bush honeysuckle, Persimmon
, Ash, Cotton
, Butternut, Black walnut, English walnut and Privet
among others.
When the eggs hatch 7-10 days later, small yellow larva
e that darken rapidly emerge. The caterpillars are solitary nighttime feeders in early stages, when they curl up in a "j" shaped pattern during the day and resemble two-toned bird droppings.
As the caterpillars age, they feed during the day. They molt 5 times. Each instar
is different, but on their sixth and final instar they become a bright green color, with huge black-tipped red horns, earning them their common name "hickory horned devils". They feed heavily on their host plant and can grow up to 15cm long. Their scary appearance is purely a ruse; the spines, though prickly, do not sting, and the larva is harmless and actually one of the more easily handled of the saturniidae.
Just before pupation, the larva expels its gut and changes color from Frankenstein-green to a more fetching turquoise, the skin of the fully fed creature stretched shiny and tight. They then crawl down the host plant, where they burrow into the dirt and pupa
te in a well formed chamber at a depth of five to six inches. The pupae are dark brown/black in color, and have a relatively short cremaster
. Some pupae overwinter for 2 seasons, perhaps as an adaption to variable and adverse conditions such as fires and flooding, or to maintain genetic diversity across generations.
When the moths eclose
, they have to pump their wings with fluid (hemolymph
) to extend them. The females emit pheromones, which the male can detect through its large, plumose antennae
. Males can fly for miles in order to reach a female. After the moths mate, the female spends the majority of the remainder of her life laying eggs, while the male may mate several more times. Adults of this family of moths have vestigal
mouths, meaning their mouthparts have been reduced. Because of this, they do not eat and only live for about a week as adults.
There is a single generation of regalis throughout its range, but in the deep south, moths have been recorded throughout the longer growing season. Typically, Citheronia regalis is a midsummer moth, on the wing from late June through August. There is a distinct bell curve to the emergence, with peak-weeks coinciding with the first spell of the humid summer weather which may synchronize emergences.
, becoming rarer and more sporadic northward. Historically recorded throughout New England
, the species suffered a decline in the Atlantic Northeast
during the mid-20th century. This may be related to DDT
spraying, the use of Bt to combat gypsy moth infestation, and the deployment of the non-native Compsilura
fly as a bio-control agent backfiring in producing declines of saturniid species.
Excluding sparse contemporary records from New York
, Citheronia regalis achieves range stability in the mid Atlantic states and southern Appalachia
, beginning from southern New Jersey
west throughout the Ohio Valley, the edge of the Great Plains
states and south to East Texas
.
Moth
A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth , with thousands of species yet to be described...
in the saturniidae
Saturniidae
The Saturniidae, commonly known as saturniids, are among the largest and most spectacular of the moths. They form a family of Lepidoptera, with an estimated 1,300 to 1,500 described species worldwide...
family. The caterpillars are called hickory horned devils. The adult (Imago
Imago
In biology, the imago is the last stage of development of an insect, after the last ecdysis of an incomplete metamorphosis, or after emergence from the pupa where the metamorphosis is complete...
) has a wingspan of 9.5-15.5 cm.
Life cycle
Citheronia regalis The adult moth is the largest moth by mass in latitudes north of MexicoMexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
, as are the spectacular larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
and the substantial pupa
Pupa
A pupa is the life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago...
.
The life cycle of the moth is typical of the Saturniidae species, and typical of the Ceratocampinae
Ceratocampinae
Ceratocampinae is a subfamily of the family Saturniidae.This subfamily contains the following genera:*Adelocephala Herrich-Schäffer, 1854*Adeloneivaia Travassos, 1940*Adelowalkeria Travassos, 1941*Almeidella Oiticica, 1946...
. It burrows into the ground to pupate in an earthen chamber, rather than spinning a cocoon.
Yellowish eggs, oval and 2 mm in diameter, are laid either singly or in groups of up to four on the upper surface of the host
Host (biology)
In biology, a host is an organism that harbors a parasite, or a mutual or commensal symbiont, typically providing nourishment and shelter. In botany, a host plant is one that supplies food resources and substrate for certain insects or other fauna...
plant leaves, favoring nut trees such as Juglans and Carya (walnut and hickories). There are regional preferences, with the utilization of sweet gum and persimmon in the south, and sumacs where the others are not available. Larvae are solitary in later stages and rarely occur in numbers large enough to cause defoliation, however an individual larva can strip several branches of their leaves during the ravenous 5th instar
Instar
An instar is a developmental stage of arthropods, such as insects, between each molt , until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or assume a new form. Differences between instars can often be seen in altered body proportions, colors, patterns, or...
.
The general list of recorded hosts contains hickories (Carya glabra, Carya illinoensis, Carya ovata), Buttonbush
Cephalanthus occidentalis
Cephalanthus occidentalis is a species of flowering plant in the coffee family, Rubiaceae, that is native to eastern and southern North America. Common names include Buttonbush, Common Buttonbush, Button-willow and Honey-bells....
, Filbert, Bush honeysuckle, Persimmon
Diospyros virginiana
Diospyros virginiana, commonly called the American persimmon, common persimmon, Eastern persimmon, "'simmon" and "possumwood", is a persimmon species known by a variety of names including. It ranges from New England to Florida, and west to Texas, Louisiana, Oklahoma, and Kansas...
, Ash, Cotton
Gossypium herbaceum
Gossypium herbaceum, also called Levant cotton, is a species of cotton native to the semi-arid regions of sub-Saharan Africa and Arabia where it still grows in the wild as a perennial shrub...
, Butternut, Black walnut, English walnut and Privet
Ligustrum
Ligustrum is a genus of about forty species of erect, deciduous or evergreen shrubs, sometimes forming small or medium-sized trees. They are now all known by the common name of privet.-Selected species:...
among others.
When the eggs hatch 7-10 days later, small yellow larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e that darken rapidly emerge. The caterpillars are solitary nighttime feeders in early stages, when they curl up in a "j" shaped pattern during the day and resemble two-toned bird droppings.
As the caterpillars age, they feed during the day. They molt 5 times. Each instar
Instar
An instar is a developmental stage of arthropods, such as insects, between each molt , until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or assume a new form. Differences between instars can often be seen in altered body proportions, colors, patterns, or...
is different, but on their sixth and final instar they become a bright green color, with huge black-tipped red horns, earning them their common name "hickory horned devils". They feed heavily on their host plant and can grow up to 15cm long. Their scary appearance is purely a ruse; the spines, though prickly, do not sting, and the larva is harmless and actually one of the more easily handled of the saturniidae.
Just before pupation, the larva expels its gut and changes color from Frankenstein-green to a more fetching turquoise, the skin of the fully fed creature stretched shiny and tight. They then crawl down the host plant, where they burrow into the dirt and pupa
Pupa
A pupa is the life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago...
te in a well formed chamber at a depth of five to six inches. The pupae are dark brown/black in color, and have a relatively short cremaster
Cremaster
Cremaster is a term derived from the Greek verb κρεμάννυμι = "I hang ", not from Latin cremare = "to burn". It may refer to:* The cremaster muscle, part of genital anatomy in human males** Cremaster reflex, a reflex in the muscle...
. Some pupae overwinter for 2 seasons, perhaps as an adaption to variable and adverse conditions such as fires and flooding, or to maintain genetic diversity across generations.
When the moths eclose
Eclose
Eclose is a commune in the Isère department in south-eastern France....
, they have to pump their wings with fluid (hemolymph
Hemolymph
Hemolymph, or haemolymph, is a fluid in the circulatory system of some arthropods and is analogous to the fluids and cells making up both blood and interstitial fluid in vertebrates such as birds and mammals...
) to extend them. The females emit pheromones, which the male can detect through its large, plumose antennae
Antenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....
. Males can fly for miles in order to reach a female. After the moths mate, the female spends the majority of the remainder of her life laying eggs, while the male may mate several more times. Adults of this family of moths have vestigal
Vestigial structure
Vestigiality describes homologous characters of organisms that have seemingly lost all or most of their original function in a species through evolution. These may take various forms such as anatomical structures, behaviors and biochemical pathways. Some of these disappear early in embryonic...
mouths, meaning their mouthparts have been reduced. Because of this, they do not eat and only live for about a week as adults.
There is a single generation of regalis throughout its range, but in the deep south, moths have been recorded throughout the longer growing season. Typically, Citheronia regalis is a midsummer moth, on the wing from late June through August. There is a distinct bell curve to the emergence, with peak-weeks coinciding with the first spell of the humid summer weather which may synchronize emergences.
Range
Citheronia regalis is considered a common species in the Deep SouthDeep South
The Deep South is a descriptive category of the cultural and geographic subregions in the American South. Historically, it is differentiated from the "Upper South" as being the states which were most dependent on plantation type agriculture during the pre-Civil War period...
, becoming rarer and more sporadic northward. Historically recorded throughout New England
New England
New England is a region in the northeastern corner of the United States consisting of the six states of Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, and Connecticut...
, the species suffered a decline in the Atlantic Northeast
Atlantic Northeast
The Atlantic Northeast, or Arcadia, is a region of North America, comprising New Hampshire, Vermont, Maine and the Canadian Maritimes. Definitions of the region vary; it may extend to upstate New York and/or all of Atlantic Canada....
during the mid-20th century. This may be related to DDT
DDT
DDT is one of the most well-known synthetic insecticides. It is a chemical with a long, unique, and controversial history....
spraying, the use of Bt to combat gypsy moth infestation, and the deployment of the non-native Compsilura
Compsilura
Compsilura concinnata is a parasitoid native to Europe that was introduced to North America in 1906 to control the population of an exotic forest, univoltine, gypsy moth named Lymantria dispar. It is an endoparasitoid of larvae and lives with its host for most of its life. Eventually the...
fly as a bio-control agent backfiring in producing declines of saturniid species.
Excluding sparse contemporary records from New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...
, Citheronia regalis achieves range stability in the mid Atlantic states and southern Appalachia
Appalachia
Appalachia is a term used to describe a cultural region in the eastern United States that stretches from the Southern Tier of New York state to northern Alabama, Mississippi, and Georgia. While the Appalachian Mountains stretch from Belle Isle in Canada to Cheaha Mountain in the U.S...
, beginning from southern New Jersey
New Jersey
New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...
west throughout the Ohio Valley, the edge of the Great Plains
Great Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...
states and south to East Texas
East Texas
East Texas is a distinct geographic and ecological area in the U.S. state of Texas.According to the Handbook of Texas, the East Texas area "may be separated from the rest of Texas roughly by a line extending from the Red River in north central Lamar County southwestward to east central Limestone...
.
External links
- Bugguide-caterpillar pictures
- Description, with pictures
- Photos of the Hickory Horned Devil Caterpillar
- Regal Moth on the UFUniversity of FloridaThe University of Florida is an American public land-grant, sea-grant, and space-grant research university located on a campus in Gainesville, Florida. The university traces its historical origins to 1853, and has operated continuously on its present Gainesville campus since September 1906...
/ IFASInstitute of Food and Agricultural SciencesThe University of Florida’s Institute of Food and Agricultural Sciences is a federal-state-county partnership dedicated to developing knowledge in agriculture, human and natural resources, and the life sciences, and enhancing and sustaining the quality of human life by making that information...
Featured Creatures Web site - The King of the Poets: Citheronia Regalis. Chapter 15 of Gene Stratton Porter's "Moths of the Limberlost" (1912).