Nymphalis antiopa

Nymphalis antiopa, known as the Mourning Cloak in North America and the Camberwell Beauty in Britain, is a large butterfly native to Eurasia and North America. See also Anglewing butterflies.

The immature form of this species is sometimes known as the spiny elm caterpillar.^[1] Other older names for this species include Grand Surprise and White Petticoat. A powerful flier, this species is sometimes found in areas far from its usual range during migration.

These butterflies have a life-span of 11 to 12 months, one of the most extensive life-spans for any butterfly.^[2]

It is also the State Insect of Montana, adopted in 2001.^[3]

Etymology

The North American name "Mourning Cloak"

In several European countries with Germanic languages, other than Britain, the name for this butterfly literally translates to "Mourning Cloak", such as German "Trauermantel", Swedish "sorgmantel", Finnish "suruvaippa" and Norwegian "Sørgekåpe". This suggests it is a name which came with Scandinavian or German rather than with British settlers, for whom this species would be considerably less familiar.^[4][5]

The British name "Camberwell Beauty"

The name originated from the discovery of two individuals at Coldharbour Lane in Camberwell in August 1748.^[6] Camberwell is in South London, about three miles south of London Bridge—in reporting this, the author Harris named the species Grand Surprise or Camberwell Beauty (Bretherton & Emmet, 1990). It has been suggested that the "pair" were stowaways on ships bringing timber from Scandinavia.

Distribution

The mourning cloak butterflies are distributed broadly around the world. They are commonly found in North America and northern Eurasia, as well as in Mexico.^[7] Mourning cloak butterflies are prevalent throughout North America. They can usually be found in hardwood forests, though they have been found in virtually all habitats.^[8] They may also be found as far as the northern part of South America, though they are typically not seen as frequently in southern states such as Florida, Louisiana, or Texas. They are occasionally seen in the more temperate places in Asia, and a few have even been seen in Japan.^[6] However, the mourning cloaks tend to be found predominantly in cold, mountainous areas.^[6]

Migrants arrive in Great Britain most years during summer and autumn, but numbers are usually very low. There is no evidence that the species breeds in Britain; it is thought that mild, wet winters prevent them from surviving there for very long. The 'Butterfly Farmer' L. Hugh Newman raised thousands for release at his 'farm' in Bexley, but none were seen the following spring. Specimens stored in his refrigerator for the winter survived however. In a book he said that Camberwell Beauty catches in England were suspiciously concentrated around London and Hull and Harwich, all these being ports in the timber trade with Scandinavia, and theorized that they had hibernated in stacks of timber which was then shipped to England, and had not travelled naturally.

Morphology

Eggs

Mourning cloak eggs are first laid a pale yellow. These eggs can also be a pale olive-green bordering yellow.^[9] Upon further development, the eggs will become red, and finally black, throughout their maturation prior to hatching.^[2] The eggs are generally 0.7 by 0.9 mm in size.^[6]

Larvae

The caterpillars are just as striking, with black bodies and a line of red dots running down the back, and dark red legs. The body is covered with black spines, white dots converging on the ends of all the spines.^[1] The mourning cloak caterpillars can grow to be up to two inches in length.^[2]

Pupae

Mourning cloak pupae are on average 0.8 inches in length, though they can reach over 2.8 cm in length. They tend to be a tan or brown-gray, with two rows of sharp, red-tipped spikes protruding from the ventro-lateral side of the pupae. The chrysalis has a "beak", tubercles, and two head horns.^[6][10]

Adult

The mourning cloak butterfly is a large, unique butterfly, with special markings that do not match those of any other butterfly, making it easily distinguishable. It can have a wingspan up to four inches. The dorsal side of its wings are a dark maroon, or occasionally brown, with ragged pale-yellow edges. Bright, iridescent blue spots line the black demarcation between the maroon and the yellow.^[2] The ventral side of the wings has grey striations, with the same pale-yellow edges.^[6] They are a part of the Nymphalis family, called the brush-footed butterflies due to their hairy front legs. The species does not display any sexual dimorphism.^[2]

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  Larva San Diego, California

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  ♂

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  ♂ △

Reproduction and development

Mating system

Mourning cloak butterflies display polygynous mating behavior, where an individual male will mate with multiple females throughout one breeding season. He will either use a display site to attract females or fly around searching for females that are more widely dispersed in a process called scramble competition polygyny.^[11] This means that male mourning cloak butterflies primarily lek, or display territorial behavior, in which they settle and defend desirable areas, such as those that either offer increased probability of females or those that provide ample amounts of good resources.^[12] The more desirable territories will be able to increase the males’ chances of reproductive success. Thus, lekking maximizes the males’ ability to attract the most female butterflies, either by being in a prime location to view them or to have a location that females would want to visit.^[13] Locations of choice typically include sunny perches near ravines,^[12] wood margins, parks, gardens, lakes, ponds, around stream edges,^[14] or canyons in which males can perch and defend for multiple days.^[13] These locations can be more than an area of 300 square meters.^[6] Given the male-male competition for mating, this strategy offers males an ideal location in order to maximize success in territorial protection, and thus mating.^[13] Despite the fact that butterflies, particularly the mourning cloak butterflies, have an affinity for perches on high objects, they are not known to display any hilltopping behavior, where male butterflies fly up to perch on hill summits.^[14][15]

Spring marks the beginning of their mating season, when female mourning cloaks will find a host plant and begin to lay their eggs. Adult mourning cloak butterflies can first be seen in late June through early July. They then aestivate for the summer, where they will enter into a “dormant” state similar to that of hibernation. In concordance with this is the mourning cloak butterflies’ exhibition of diapause,^[16] which is a suspension in development in response to certain conditions, such as environmental stimuli. They will break diapause once some, though not all, of the butterflies start to migrate through September and October. They then overwinter, and then restart their mating cycle throughout the spring, from April through June.^[7]

Life cycle

Mourning cloaks, like other butterflies, undergo complete metamorphosis.^[6] Mourning cloaks are known to lay their eggs as ring clusters around twigs on host plants. This host plant location is vital because it acts as the nutrition source for the young caterpillars. Females are known to have multiple broods,^[14] typically up to two to three.^[6] The newly hatched caterpillars will group together, until they shed their skin—termed an instar for each shedding. This shedding event occurs four times throughout development in a process called ecdysis. The larvae experience a fifth skin shed to produce a fully grown caterpillar.^[6] The next stage in the mourning cloak’s life cycle is to morph into a pupa and then cocoon in a process that encases the creature in a tan or gray chrysalis, which will hang from the stems of grass. This pupa stage allows for resting and further maturation.^[2] This metamorphosis takes approximately fifteen days.^[17] Following development as the chrysalis is the emergence of an adult mourning cloak butterfly.^[6]

Studies show that the mourning cloaks use endocrine mechanisms similar to other lepidopterans to regulate female specific protein synthesis, oogenesis, and male and female reproductive gland development. Juvenile hormone (JH) is involved in the regulation of oogenesis and development of the male and female reproductive glands in the mourning cloak butterfly.^[18]

Behavior

Migration

Mourning cloak butterflies are seen throughout the year because they do not participate in long-distance migration.^[19] Instead of migrating, there is evidence that mourning cloak butterflies exhibit overwintering. This one location is where the butterflies will hibernate during the winter. Typical locations of overwintering include tree cavities and underneath loose tree bark. This process is advantageous for the butterflies because they are able to immediately start mating in the spring, rather than having to migrate back prior to mating.^[2] They are often one of the first butterflies seen in the spring.^[6]

Ecology

Diet

The caterpillars will begin to eat the leaves of the primary host plants upon hatching. They eat a larger variety of primary host plants, such as willow and black willow, American elm, hackberry, hawthorn, wild rose, and poplar. Upon hatching, Mourning Cloaks are insatiable throughout their development as caterpillars.^[2]

Adult Mourning Cloaks feed on sap and decaying matter, less commonly they are seen nectaring on flowers. ^[20]

Predation

The mourning cloak butterfly faces many predators throughout its development. The mourning cloak’s eggs can be eaten by predators such as beetles, true bugs, ants, beetle larvae, wasps, assassin bugs, and mites.^[17] Some of the butterflies’ major predators include praying mantises, assassin bugs, dragon flies, and vertebrate predators such as birds, reptiles, amphibians, and mammals.

Defense mechanisms

An anti-predation mechanism the mourning cloaks have employed as adult butterflies is camouflage. To do this, the butterflies fold their wings back when attached to trees as their folded wings will provide camouflage against the dark backdrop of the trees.^[2][6]

An additional anti-predation tactic used by the mourning cloaks is to join together with other butterflies in a perch and fly menacingly towards their attackers—most often birds or other butterflies.

Further defense mechanisms include loud clicks when the mourning cloak flies away from a predator.^[21]

To protect themselves from the cold weather of their habitats, mourning cloaks will find areas under direct sunlight. This behavior, in conjunction with their darkly-colored wings, allow for maximum heat absorption.^[6]

Newly hatched mourning cloak caterpillars can display selfish behavior, such as siblicide, by eating non-hatched eggs.^[17] The larvae also group together for the duration of their development, preventing some predation by numbers.^[11] The larvae and pupae can also respond to disturbances by twitching simultaneously – this may be performed as a defense mechanism.^[6]

Pollination

Mourning cloak butterflies are not known to be predominant pollinators, since their primary food source are deciduous trees rather than flowers. However, they still can occasionally act as pollinators. Because of this, they do not offer hugely significant benefit to humans. In fact, they can often pose problems because, as specified previously, these larvae are known to destroy much of their host plant through clustering behavior.^[6][22]

Relationship to people

Pests

Mourning cloak butterflies can be pests. Some experiments have shown that the mourning cloak larvae will completely defoliate ornamental trees, as well as trees in nursuries, plantations, and parks. Some areas that this damage has been documented has been Oregon and Canada.^[23][24] Immature willow and poplar are often completely damaged due to the larvae, though forest trees tend not to be affected.^[23]

Research

Mourning cloak butterflies have been a part of some epigenetics experiments testing to determine if the environment affects certain butterfly phenotypic characteristics. Scientists hypothesized that traumatic heat or cold shocks “during a critical period of its development can cause profound changes”. The first experiments occurred in the 1890s. The mourning cloaks were temperature shocked at specific times in their development, which led to differences in pupae color. It was later learned that the color change was due to hormonal changes in response to varying temperatures.^[25]

In popular culture

The poem Unconscious came a beauty by May Swenson mentions the Mourning Cloak (or the similar looking Red-spotted Purple) – a butterfly that makes her pause and think, while writing. The poem is also a word-picture or iconograph – the lines are laid out to look like a butterfly. In the Doomspell Trilogy by Cliff McNish, Camberwell Beauties are the main icon of the baby Yemi. They act as his protectors and guides and Yemi's magic enlarges them to the size of cats.

Conservation

Mourning cloak butterflies are protected by law in Switzerland and Austria,^[26] though they generally have an increasing trend regarding population density in Finland.^[27] They also assume "safe" status in the Czech Republic.^[28] In general, the mourning cloak butterflies find areas that have experienced fuel breaks to be more inviting,^[29] presumably because the fuel breaks increase the amount of open space and clearings available to the butterflies, which is a more ideal habitat for these butterflies to live in.^[27]

Subspecies^[9]

• N. a. antiopa (Linnaeus, 1758)
  • This subspecies's larvae tends to have more intense red-orange spots compared to the European mourning cloak larvae.
• N. a. hyperborea (Seitz, 1914) (Alaska)
  • This subspecies lays more golden-yellow eggs, instead of the olive-green to pale yellow eggs typically seen in Nymphalis antiopa antiopa. Upon maturation, the eggs will become more pinkish-purple. These larvae's spines are shorter and stouter than those of European mourning cloak larvae. Adult N. a. hyperborea may display some more "peppering" patterns on the front part of the wing, a lighter body color,^[30] and the spots bordering the wing edges may be more of a violet color.
• N. a. asopos (Fruhstorfer, 1909) (Japan)

References

Further reading

• Glassberg, Jeffrey Butterflies through Binoculars, The West (2001) ISBN 978-0195106695
• Guppy, Crispin S. and Shepard, Jon H. Butterflies of British Columbia (2001) ISBN 978-0774808095
• James, David G. and Nunnallee, David Life Histories of Cascadia Butterflies (2011) ISBN 978-0-87071-626-3
• Pelham, Jonathan Catalogue of the Butterflies of the United States and Canada (2008) ISSN 0022 4324
• Pyle, Robert Michael The Butterflies of Cascadia (2002) ISBN 0-914516-13-2

External links

External identifiers for Nymphalis antiopa
Encyclopedia of Life	163165
ITIS	188597
NCBI	171592
Also found in: Wikispecies

• Nymphalis antiopa: Reference quality large format photographs and information Cirrus Digital Imaging
• Nymphalis antiopa at funet.fi
• Butterflies of North America - Nymphalis antiopa
• Nymphalis antiopa at Butterfliesandmoths.org
• Mourning Cloak, Canadian Biodiversity Information Facility
• mourning cloak on the UF / IFAS Featured Creatures Web site