Arctiidae: Definition and Much More from Answers.com

Arctiidae

Cinnabar moth, Tyria jacobaeae

Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Lepidoptera
Suborder:	Macrolepidoptera
Superfamily:	Noctuoidea
Family:	Arctiidae Leach, 1815

Diversity

? genera
Approximately 11,000 species

Type species

Arctia caja
Linnaeus, 1758

Subfamilies ^[1]

Arctiinae
Ctenuchinae
Lithosiinae
Pericopinae

Arctiidae is a large and diverse family of moths with around 11,000 species found all over the world, with 6000 Neotropical species (Scoble 1995). 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, however).

Diagnosis

The most distinctive feature of the family is a tymbal organ on the metathorax (Scoble 1995). This organ has membranes which are vibrated to produce ultrasonic sounds. They also have thoracic tympanal organs 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 (Scoble, 1995). The sounds are used in mating (Simmons and Conner 1996) and defense against predators (Fullard et al, 1994).

Aposematism

Many species retain distasteful or poisonous chemicals acquired from their host plants (Weller et al., 1999). Some species also have the ability to make their own defenses (Nishida, 2002). Common defenses include: cardiac glycosides (or cardenolides), pyrrolizidine alkaloids, pyrazines and histamines (Weller et al., 1999). 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 (Weller et al., 1999). 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 bright coloration, unusual postures, odours, or, in adults, ultrasonic vibrations. Some mimic moths that are poisonous, or wasps that sting (Simmons and Weller, 2002). The ultrasound signals help nocturnal predators to learn to avoid the moths (Dunning and Roeder 1965, Hristov and Conner, 2005), and can interfere with the bat's ability to precisely locate flying moths (Ratcliffe and Fullard, 2005).

Life cycle

Many of the caterpillars and adults are active during the daytime. If disturbed, woolly bear caterpillars will roll into a tight spiral. Common folklore has it that the forthcoming severity of a winter can be predicted by the amount of black on the Isabella tiger moth's caterpillar, the most familiar woolly bear in North America; however the relative width of the black band varies among instars, not according to weather (Wagner 2005). Isabella tiger moths (Pyrrharctia isabella) overwinter in the caterpillar stage. They can survive freezing at moderate subzero temperatures by producing a cryo-protectant chemical (Layne and Kuharsky 2000). The larvae of another species, Phragmatobia fuliginosa may be found on snow seeking a place to pupate.

Although they may be abundant, few species in this family are of economic importance. Even the fall webworm, 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.

Notable species

Banded tussock moth, Halysidota tesselaris
Banded woolly bear or Isabella tiger moth, Pyrrharctia isabella
Buff Ermine, Spilarctia luteum
Cinnabar moth, Tyria jacobaeae
Common Footman, Eilema lurideola
Dogbane tiger moth or Delicate Cycnia, Cycnia tenera
Fall webworm, Hyphantria cunea
Garden tiger moth, Arctia caja
Giant Leopard Moth, Hypercompe scribonia
Hickory tussock moth, Lophocampa caryae
Milkweed tussock moth, Euchaetes egle
Scarlet tiger moth, Callimorpha dominula
Maltese Ruby Tiger Moth, Phragmatobia fuliginosa ssp. melitensis

Gallery

Grammia parthenice	Scarlet tiger moth, Callimorpha dominula	Giant Leopard Moth, Hypercompe scribonia	Magpie Moth, Nyctemera annulata
Banded woolly bear, Pyrrharctia isabella	Arctia villica	Late instar of Milkweed tussock moth, Euchaetes egle	Woolly bear caterpillar

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, Roeder KD (1965) Moth sounds and the insect-catching behavior of bats. Science 147:173–174
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
Fullard JH, Simmons JA, Sailant PA (1994) Jamming bat echolocation: the dogbane tiger moth Cycnia tenera times its clicks to the terminal attack calls of the big brown bat Eptesicus fuscus. J Exp Biol 194:285–298
Hristov NI, Conner WE (2005) Sound strategy: acoustic aposematism in the bat–tiger moth arms race. Naturwissenschaften 92:164–169. DOI:10.1007/s00114-005-0611-7
Layne JR, Kuharsky DK (2000) Triggering of cryoprotectant synthesis in the woolly bear caterpillar (Pyrrharctia isabella Lepidoptera : Arctiidae). J Exper Zool 286 (4): 367-371
Scoble, MJ. (1995) The Lepidoptera: Form, Function and Diversity. Second ed. Oxford University Press.
Simmons RB, Conner WE (1996) Ultrasonic signals in the defense and courtship of Euchaetes egle Drury and E. bolteri Stretch (Lepidoptera: Arctiidae). J Ins Behav 9 (6): 909-919
Simmons RB, Weller SE (2002) What kind of signals do mimetic tiger moths send? A phylogenetic test of wasp mimicry systems (Lepidoptera: Arctiidae: Euchromiini). Proc Roy Soc Lond B 269: 983–990
Wagner, DL, (2005) Caterpillars of Eastern North America. Princeton University Press.
Weller SJ, Jacobsen NL, Conner WE (1999) The evolution of chemical defenses and mating systems in tiger moths (Lepidoptera: Arctiidae). Biol J Linn Soc 68:557–578.

Arthropoda - Insecta - Families of Lepidoptera

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