Arctiidae is a large and diverse family of 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...

s with around 11,000 species found all over the world, including 6,000 neotropical species. This family includes the groups commonly known as tiger moths (or tigers), which usually have bright colours, footmen (which are usually much drabber), lichen moths and wasp moths. Many species have 'hairy' caterpillars which are popularly known as woolly bears or woolly worms. The scientific name refers to this (Gk. αρκτος = a bear). Caterpillars may also go by the name 'tussock moths' (more usually this refers to Lymantriidae
Lymantriidae is a family of moths. Many of its component species are referred to as "Tussock moths" of one sort or another. The caterpillar, or larval, stage of these species often has a distinctive appearance of alternating bristles and haired projections...

, however).


The most distinctive feature of the family is a tymbal organ on the metathorax. This organ has membranes which are vibrated to produce ultrasonic sounds. They also have thoracic tympanal organ
Tympanal organ
A tympanal organ is a hearing organ in insects, consisting of a membrane stretched across a frame backed by an air sac and associated sensory neurons...

s for hearing, a trait which has a fairly broad distribution in the Lepidoptera, but the location and structure is distinctive to the family. Other distinctive traits are particular setae ('hairs') on the larvae, wing venation, and a pair of glands near the ovipositor. The sounds are used in mating and for defense against predators. Another good distinguishing character of the family is presence of anal glands in females


Many species retain distasteful or poisonous chemicals acquired from their host plants. Some species also have the ability to make their own defenses (Nishida, 2002). Common defenses include: cardiac glycosides (or cardenolide
Cardenolide is a type of steroid. Many plants contain derivatives, collectively known as cardenolides, including many in the form of cardenolide glycosides...

s), pyrrolizidine alkaloids, pyrazines and histamine
Histamine is an organic nitrogen compound involved in local immune responses as well as regulating physiological function in the gut and acting as a neurotransmitter. Histamine triggers the inflammatory response. As part of an immune response to foreign pathogens, histamine is produced by...

s. Larvae usually acquire these chemicals, and may retain them in the adult stage. But adults can acquire them too, by regurgitating on decomposing plants containing the compounds, and sucking up the fluid. Adults can transfer the defenses to their eggs, and males sometimes transfer them to females to help with defense of the eggs. Larval 'hairs' may be stinging, due to histamines the caterpillar makes, in some species but not all.

The insects advertise these defenses with aposematic
Aposematism , perhaps most commonly known in the context of warning colouration, describes a family of antipredator adaptations where a warning signal is associated with the unprofitability of a prey item to potential predators...

 bright coloration, unusual postures, odours, or, in adults, ultrasonic vibrations. Some mimic moths that are poisonous, or wasp
The term wasp is typically defined as any insect of the order Hymenoptera and suborder Apocrita that is neither a bee nor an ant. Almost every pest insect species has at least one wasp species that preys upon it or parasitizes it, making wasps critically important in natural control of their...

s that sting. The ultrasound signals help nocturnal predators to learn to avoid the moths, and can interfere with bats' ability to precisely locate flying moths (Ratcliffe and Fullard, 2005).

Behavior and life cycle

Many of the caterpillars and adults are active during the daytime. If disturbed, woolly bear caterpillars will roll into a tight spiral. Isabella tiger moths (Pyrrharctia isabella) overwinter in the caterpillar stage. They can survive freezing at moderate subzero temperatures by producing a cryo-protectant chemical. The larvae of another species, Phragmatobia fuliginosa may be found on snow seeking a place to pupate.

Although abundant, few species in this family are of economic importance. Even the fall webworm
Fall webworm
Fall webworm, Hyphantria cunea, is a moth in the family Arctiidae known principally for its larval stage, which creates the characteristic webbed nests on the tree limbs of a wide variety of hardwoods in the late summer and fall. It is mainly an aesthetic pest and is not believed to harm otherwise...

, an abundant and highly polyphagous tree-feeding species that has spread from North America to Asia and Europe, does not do lasting damage to healthy hosts.


Local folklore
Folklore consists of legends, music, oral history, proverbs, jokes, popular beliefs, fairy tales and customs that are the traditions of a culture, subculture, or group. It is also the set of practices through which those expressive genres are shared. The study of folklore is sometimes called...

 of the American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

Northeastern United States
The Northeastern United States is a region of the United States as defined by the United States Census Bureau.-Composition:The region comprises nine states: the New England states of Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island and Vermont; and the Mid-Atlantic states of New...

 holds that "woolly bears" have the ability to predict the weather, similar to that of the Groundhog
The groundhog , also known as a woodchuck, whistle-pig, or in some areas as a land-beaver, is a rodent of the family Sciuridae, belonging to the group of large ground squirrels known as marmots. Other marmots, such as the yellow-bellied and hoary marmots, live in rocky and mountainous areas, but...

. The forthcoming severity of a winter may be indicated by the amount of black on the Isabella tiger moth's caterpillar, the most familiar woolly bear in North America; more brown than black means a fair winter, but more black than brown means a harsh winter. However, the relative width of the black band varies among 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...

s, not according to weather. The mythical qualities attributed to woolly bears in the American Northeast have led to such things as the Woollybear Festival
Woollybear Festival
The annual Woollybear Festival is held every Fall in downtown Vermilion, Ohio, on Lake Erie. The one-day, family event, which began in 1973, features a woolly bear costume contest in which children, even pets, are dressed up as various renditions of the woolly bear caterpillar.The festival,...


Notable species

  • banded tussock moth, Halysidota tesselaris
  • banded woolly bear or Isabella tiger moth, Pyrrharctia isabella
  • buff ermine
    Buff Ermine
    The Buff Ermine is a moth of the family Arctiidae. It is sometimes placed in the genus Spilosoma. It is found throughout the temperate belt of the Palearctic region south to Northern Turkey, Georgia, Kazakhstan; also in Southern Siberia , Eastern Mongolia, Amur Region, China, Korea and Japan.The...

    , Spilarctia lutea
  • cinnabar moth
    Cinnabar moth
    The Cinnabar moth is a brightly coloured arctiid moth, found in Europe and western and central Asia. It has been introduced into New Zealand, Australia and North America to control poisonous ragwort, which its larvae feed on. The moth is named after the red mineral cinnabar because of the red...

    , Tyria jacobaeae
  • common footman
    Common Footman
    The Common Footman is a moth of the family Arctiidae. It is distributed throughout the Palearctic region and the Near East....

    , Eilema lurideola
  • dogbane tiger moth or Delicate Cycnia, Cycnia tenera
  • fall webworm
    Fall webworm
    Fall webworm, Hyphantria cunea, is a moth in the family Arctiidae known principally for its larval stage, which creates the characteristic webbed nests on the tree limbs of a wide variety of hardwoods in the late summer and fall. It is mainly an aesthetic pest and is not believed to harm otherwise...

    , Hyphantria cunea
  • garden tiger moth
    Garden tiger moth
    The garden tiger moth is a moth of the Arctiidae family.It has a wingspan of . The design of the wings varies: the front wings are brown with a white pattern , the back wings orange with a pattern of black dots. The conspicuous patterns serve as a warning to predators, because the moth's body...

    , Arctia caja
  • giant leopard moth, Hypercompe scribonia
  • hickory tussock moth, Lophocampa caryae
  • Jersey tiger moth, Euplagia quadripunctaria
  • milkweed tussock moth, Euchaetes egle
  • scarlet tiger moth
    Scarlet tiger moth
    The Scarlet Tiger Moth is a colorful moth of Europe, Turkey, Transcaucasus, northern Iran. It belongs to the tiger moth family, Arctiidae....

    , Callimorpha dominula
  • Maltese ruby tiger moth
    Maltese Ruby Tiger Moth
    The Maltese Ruby Tiger Moth is a moth endemic to the Maltese Islands which falls under the family Arctiidae.-General features:...

    , Phragmatobia fuliginosa ssp. melitensis

Other references

  • Bates DL, Fenton MB (1990) Aposematism or startle? Predators learn their responses to the defenses of prey. Can J Zool 68:49–52
  • Dunning DC, Krüger M (1995) Aposematic sounds in African moths. Biotropica 27:227–231
  • Dunning DC, Acharya L, Merriman CB, Ferro LD (1992) Interactions between bats and arctiid moths. Can J Zool 70:2218–2223
  • Fullard JH, Fenton MB, Simmons JA (1979) Jamming bat echolocation: the clicks of arctiid moths. Can J Zool 57:647–649
  • Science Fridays: Moths Can Escape Bats By Jamming Sonar

Main species catalogs

  • Dubatolov VV (2010) Tiger-moths of Eurasia (Lepidoptera, Arctiidae) (Nyctemerini by Rob de Vos & Vladimir V. Dubatolov). Neue Entomologische Nachrichten 65:1-106
  • Edwards ED (1996) Arctiidae. Monographs on Australian Lepidoptera 4:278-286,368-370
  • Ferguson DC, Opler PA (2006) Checklist of the Arctiidae (Lepidoptera: Insecta) of the continental United States and Canada. Zootaxa 1299:1-33
  • Goodger DT, Watson A (1995) The Afrotropical Tiger-Moths. An illustrated catalogue, with generic diagnosis and species distribution, of the Afrotropical Arctiinae (Lepidoptera: Arctiidae). Apollo Books Aps.: Denmark, 55 pp.
  • Watson A (1971) An illustrated Catalog of the Neotropic Arctiinae type in the United States National Museum (Lepidoptera: Arctiidae) Part 1. Smithsonian Contributions to Zoology 50:1-361
  • Watson A, Goodger DT (1986) Catalogue of the Neotropical Tiger-moths. Occasional Papers on Systematic Entomology 1:1-71

Phylogenetic analyses

  • Da Costa MA, Weller SJ (2005) Phylogeny and classification of Callimorphini (Lepidoptera: Arctiidae: Arctiinae). Zootaxa 1025:1-94
  • Dubatolov VV (2006) Cladogenesis of tiger-moths of the subfamily Arctiinae: development of a cladogenetic model of the tribe Callimorphini (Lepidoptera, Arctiidae) by the SYNAP method. Euroasian Entomological Journal 5(2):95-104 (in Russian).
  • Dubatolov VV (2008) Construction of the phylogenetic model for the genera of the tribe Arctiini (Lepidoptera, Arctiidae) with the SYNAP method. Entomological Review 88(7):833-837. Translated from: Entomologicheskoe Obozrenie 87(3):653-658
  • Dubatolov VV (2009) Development of a phylogenetic model for the tribe Micrarctiini (Lepidoptera, Arctiidae) by the SYNAP method. Entomological Review 89(3):306-313. Translated from: Zoologicheskii Zhurnal. 88(4):438-445
  • Jacobson NL, Weller SJ (2002) A cladistic study of the Arctiidae (Lepidoptera) by using characters of immatures and adults. Thomas Say publications in entomology. Entomologica Society of America | Lanham, Maryland
    Lanham, Maryland
    Lanham is an unincorporated community in Prince George's County in the State of Maryland in the United States of America. Because it is not formally incorporated, it has no official boundaries, but the United States Census Bureau has defined a census-designated place consisting of Lanham and the...

    , 98 pp.

Distribution analyses

  • Dubatolov VV (2008) Analysis of Insect Distribution in the Northern Hemisphere by the Example of the Subfamily Arctiinae (Lepidoptera, Artctiidae). Contemporary Problems of Ecology 1(2):183-193, 194-203.

Further reading

  • William Conner (ed.). (2009). Tiger moths and woolly bears : behavior, ecology, and evolution of the Arctiidae. Oxford University Press
    Oxford University Press
    Oxford University Press is the largest university press in the world. It is a department of the University of Oxford and is governed by a group of 15 academics appointed by the Vice-Chancellor known as the Delegates of the Press. They are headed by the Secretary to the Delegates, who serves as...

    : New York
    New York City
    New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...

    . ISBN 9780195327373

External links

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