''Automeris io'', the Io moth () or peacock moth, is a colorful North American moth in the family

Saturniidae Saturniidae, members of which are commonly named the saturniids, is a family of Lepidoptera with an estimated 2,300 described species. The family contains some of the largest species of moths in the world. Notable members include the emperor m ...

. The Io moth is also a member of the subfamily Hemileucinae. The name Io comes from

Greek mythology Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of ancient Greek folklore, today absorbed alongside Roman mythology into the broader designation of classical mythology. These stories conc ...

in which Io was a mortal lover of Zeus. The Io moth ranges from the southeast corner of

Manitoba Manitoba is a Provinces and territories of Canada, province of Canada at the Centre of Canada, longitudinal centre of the country. It is Canada's Population of Canada by province and territory, fifth-most populous province, with a population ...

and in the southern extremes of

Ontario Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...

Quebec Quebec is Canada's List of Canadian provinces and territories by area, largest province by area. Located in Central Canada, the province shares borders with the provinces of Ontario to the west, Newfoundland and Labrador to the northeast, ...

New Brunswick New Brunswick is a Provinces and Territories of Canada, province of Canada, bordering Quebec to the north, Nova Scotia to the east, the Gulf of Saint Lawrence to the northeast, the Bay of Fundy to the southeast, and the U.S. state of Maine to ...

and

Nova Scotia Nova Scotia is a Provinces and territories of Canada, province of Canada, located on its east coast. It is one of the three Maritime Canada, Maritime provinces and Population of Canada by province and territory, most populous province in Atlan ...

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

, and in the US it is found from

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...

North Dakota North Dakota ( ) is a U.S. state in the Upper Midwest, named after the indigenous Dakota people, Dakota and Sioux peoples. It is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north and by the U.S. states of Minneso ...

South Dakota South Dakota (; Sioux language, Sioux: , ) is a U.S. state, state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Dakota people, Dakota Sioux ...

Nebraska Nebraska ( ) is a landlocked U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Ka ...

Colorado Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas ...

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...

, east of those states and down to the southern end of

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

. The species was first described by

Johan Christian Fabricius Johann Christian Fabricius (7 January 1745 – 3 March 1808) was a Danish zoologist, specialising in "Insecta", which at that time included all arthropods: insects, arachnids, crustaceans and others. He was a student of Carl Linnaeus, and is co ...

in 1775.

Adult description

Imagines (sexually mature, reproductive stage) have a wingspan of 2.5–3.5 inches (63–88 mm). This species is

sexually dimorphic Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

: males have bright yellow forewings, body, and legs, while females have reddish-brown to purple forewings, body, and legs. The males also have much bigger plumose (feathery) antennae than the females. Both males and females have one big black to bluish eyespot with some white in the center, on each hindwing. Some hybridizations have resulted in variations in these hindwing eyespots. Adults live 1–2 weeks.

Parasitoids

Many species of flies (

Tachinidae The Tachinidae are a large and variable family of true fly, flies within the insect order Fly, Diptera, with more than 8,200 known species and many more to be discovered. Over 1,300 species have been described in North America alone. Insects in t ...

) and wasps (

Ichneumonidae The Ichneumonidae, also known as ichneumon wasps, ichneumonid wasps, ichneumonids, or Darwin wasps, are a family of parasitoid wasps of the insect order Hymenoptera. They are one of the most diverse groups within the Hymenoptera with roughly 25 ...

and

Braconidae The Braconidae are a family of parasitoid wasps. After the closely related Ichneumonidae, braconids make up the second-largest family in the order Hymenoptera, with about 17,000 recognized species and many thousands more undescribed. One analysis ...

) are known parasitoids. The flies include the introduced '' Compsilura concinnata'', '' Lespesia sabroskyi'', '' Chetogena claripennis'', '' Carcelia formosa'', '' Sisyropa eudryae'', '' Lespesia frenchii'', and '' Nilea dimmocki''. The wasps include the

species '' Hyposoter fugitivus'' and '' Enicospilus americanus'', and the

species '' Cotesia electrae'' and '' Cotesia hemileucae''.

Predators

Io moths have many

predators Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...

. These include

bat Bats are flying mammals of the order Chiroptera (). With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most birds, flying with their very long spread-out ...

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

s, small mammals, and

spider Spiders (order (biology), order Araneae) are air-breathing arthropods that have eight limbs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude spider silk, silk. They are the largest order of arachnids and ran ...

Defenses

Stinging spines of

caterpillar Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder ...

Io moths have a very painful

venom Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...

that is released with the slightest touch. There are two hypotheses regarding where this

originates: (1) the glandular cells on the base of the branched

seta In biology, setae (; seta ; ) are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Depending partly on their form and function, protostome setae may be called macrotrichia, chaetae, ...

or (2) from the secretory

epithelial Epithelium or epithelial tissue is a thin, continuous, protective layer of cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial ( mesothelial) tissues line the outer surfaces of man ...

cells. Contacting the

is not life-threatening for humans, but still causes irritation to the

dermal The dermis or corium is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided i ...

tissue, resulting in an acute dermatitis called . Both male and female adult io moths utilize their hindwing eyespots in predatory defense when the moth is sitting in the head-down position or is touched, via shaking and exposing these eyespots.

Life cycle

Females lay small, white ova in the leaves of many

host A host is a person responsible for guests at an event or for providing hospitality during it. Host may also refer to: Places * Host, Pennsylvania, a village in Berks County * Host Island, in the Wilhelm Archipelago, Antarctica People * ...

plants, including: * ''

Morus alba Morus may refer to: People * Alexander Morus (1616–1670), Franco-Scottish Protestant preacher * Henryk Moruś (1943–2013), Polish serial killer * Huw Morus (1622–1709), Welsh poet * Thomas More or Morus (1478–1535), English philosopher * M ...

''—mulberry * '' Prunus pensylvanica''—pin cherry * ''

Salix Willows, also called sallows and osiers, of the genus ''Salix'', comprise around 350 species (plus numerous hybrids) of typically deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions. Most species are known ...

''—willow * ''

Abies balsamea ''Abies balsamea'' or balsam fir is a North American fir, native to most of eastern and central Canada (Newfoundland (island), Newfoundland west to central Alberta) and the northeastern United States (Minnesota east to Maine, and south in the Ap ...

''—balsam fir * ''

Acer rubrum ''Acer rubrum'', the red maple, also known as swamp maple, water maple, or soft maple, is one of the most common and widespread deciduous trees of eastern and central North America. The U.S. Forest Service recognizes it as the most abundant nati ...

''—red maple * '' Amorpha fruticosa''—bastard indigo * '' Baptisia tinctoria''—wild indigo * '' Carpinus caroliniana''—American hornbeam * '' Celtis laevigata''—sugarberry or southern hackberry * ''

Cephalanthus occidentalis ''Cephalanthus occidentalis'' is a species of flowering plant in the family Rubiaceae that is native to eastern and southern North America. Common names include buttonbush, common buttonbush, button-willow, buck brush, and honey-bells. Descripti ...

''—button-bush * '' Cercis canadensis''—eastern redbud * '' Chamaecrista fasciculata''—showy partridge pea * '' Comptonia peregrina''—sweetfern * ''

Cornus florida ''Cornus florida'', the flowering dogwood, is a species of flowering plant, flowering tree in the family Cornaceae native to eastern North America and northern Mexico. An endemic population once spanned from southernmost coastal Maine south to n ...

''—flowering dogwood * ''

Corylus avellana ''Corylus avellana'', the common hazel, is a species of flowering plant in the birch tree, birch family Betulaceae. The shrubs usually grow tall. The nut is round, in contrast to the longer Corylus maxima, filbert nut. Common hazel is native to E ...

''—common hazel * '' Erythrina herbacea''—coral bean * ''

Fagus Beech (genus ''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to subtropical (accessory forest element) and temperate (as dominant element of Mesophyte, mesophytic forests) Eurasia and North America. There are 14 accepted ...

''—beech * ''

Fraxinus ''Fraxinus'' (), commonly called ash, is a genus of plants in the olive and lilac family, Oleaceae, and comprises 45–65 species of usually medium-to-large trees, most of which are deciduous trees, although some Subtropics, subtropical specie ...

''—ash * ''

Liquidambar styraciflua ''Liquidambar styraciflua'', commonly known as the American sweetgum among other names, is a deciduous tree in the genus ''Liquidambar'' native to warm temperate areas of eastern North America and tropical montane regions of Mexico and Central A ...

''—American sweetgum * '' Lythrum salicaria''—introduced purple loosestrife * ''

Quercus An oak is a hardwood tree or shrub in the genus ''Quercus'' of the beech family. They have spirally arranged leaves, often with lobed edges, and a nut called an acorn, borne within a cup. The genus is widely distributed in the Northern Hemisp ...

''—oak * '' Paeonia''—peony * '' Phoenix roebelenii'' The eggs have large micropyle rosettes that turn black as the fertile eggs develop. They are usually laid in clusters of more than twenty and hatch within 8–11 days. From the eggs, orange

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

e emerge, usually eating their egg shell soon after hatching. They go through five

instar An instar (, from the Latin '' īnstar'' 'form, likeness') is a developmental stage of arthropods, such as insects, which occurs between each moult (''ecdysis'') until sexual maturity is reached. Arthropods must shed the exoskeleton in order to ...

s, each one being a little different. Io moth after laying eggs

The

s are

herbivorous A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat n ...

and

gregarious Sociality is the degree to which individuals in an animal population tend to associate in social groups (gregariousness) and form cooperative societies. Sociality is a survival response to evolutionary pressures. For example, when a mother was ...

in all their

s, and may be seen traveling in single-file processions over the food plant. In certain regions of the country, larvae may have preferred hosts out of the long list that this species can accept elsewhere. As the

e develop, they will lose their orange color and will turn bright green and urticating, having many spines. The green

s have two lateral stripes, the upper one being bright red and the lower one being white. These

s can reach sizes of 7 cm in length. When the

s are ready, they spin a flimsy, valveless cocoon made from a dark, coarse

silk Silk is a natural fiber, natural protein fiber, some forms of which can be weaving, woven into textiles. The protein fiber of silk is composed mainly of fibroin and is most commonly produced by certain insect larvae to form cocoon (silk), c ...

. Some

e will crawl to the base of the tree and make their cocoons among

leaf A leaf (: leaves) is a principal appendage of the plant stem, stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leav ...

litter on the ground, while others will use living

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

to wrap their cocoons with. The

will turn brown and fall to the ground during fall, taking the cocoons with them. There they

pupa A pupa (; : pupae) is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their life cycle, the stages th ...

te, the

being dark brown/black. The

e also have

sexual dimorphism Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

with the females' possessing a notch on their posterior ventral aspect, while the males' pupae bear a pair of tubercles near that area with no notch. Adult Io moths normally emerge from their cocoons in late morning or early afternoon. The emergence of the adults moths is typically from June to July.

Eclosion A pupa (; : pupae) is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their life cycle, the stages th ...

(emergence from the cocoon) only takes a few minutes. After eclosing, the moths climb and hang on plants so that their furled wings can be inflated with fluid (

hemolymph Hemolymph, or haemolymph, is a fluid, similar to the blood in invertebrates, that circulates in the inside of the arthropod's body, remaining in direct contact with the animal's tissues. It is composed of a fluid plasma in which hemolymph c ...

) pumped from the body. This inflation process takes about twenty minutes. Adult moths are strictly

nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

, generally flying during the peak hours of the night. The females generally wait until nightfall and then extend a

scent gland Scent gland are exocrine glands found in most mammals. They produce semi-viscous secretions which contain pheromones and other semiochemical compounds. These odor-messengers indicate information such as status, territorial marking, mood, and se ...

from the posterior region of the

abdomen The abdomen (colloquially called the gut, belly, tummy, midriff, tucky, or stomach) is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal ...

, in order to attract males via wind-borne

pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...

s. The males use their larger antennae to detect the pheromones. After mating, the females die following egg laying. These moths have

vestigial Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on co ...

mouthparts and do not eat in the adult stage.

Conservation status

The Io moth has not been evaluated for listing on the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...

and has no special status on the U.S. Federal List. In the eastern range of the US, the populations indicate a declining and more localized trend. Automeris io Titian Peale 1833

References

External links

Site with a description and pictures
on the UF / IFAS Featured Creatures Web site {{Taxonbar , from=Q1766445 Hemileucinae Moths of North America Moths described in 1775 Taxa named by Johan Christian Fabricius