Virtual Nature Trail

Scientific name: Nymphalis antiopa
Common name: 
Mourning Cloak

(Information in this Species Page was compiled by Jennifer Sensor in Biology 220M, Spring 2005, at Penn State New Kensington)

Typically the mourning cloak (Nymphalis antiopa) is the first butterfly seen in the spring on our Nature Trail. The ability of the adults of this species to hibernate in tree holes, inside unheated buildings, and even under the loose bark of some tree species makes this early spring (mid to late March) adult emergence possible. Often there is still snow on the ground when these beautiful butterflies make their first appearances. The ability to move about in their wooded habitats very early in the season enables this species to consume their favorite food (tree sap) just as it begins its seasonal rise up through the tree’s vascular tissue. Individuals emerging from hibernation rely on vigorous thoracic muscular contractions to generate body heat and also will bask extensively with their dark, dorsal wing sides exposed to the incoming sunlight.

The mourning cloak is a medium sized to large butterfly (its body is a bit over an inch long and its wingspan may be between 2 and 4 inches). It can be found in a wide variety of habitats (pine forests, hardwood forests, open fields, city parks, suburban yards, and alongside streams and rivers) throughout North America from the edges of northern tundra to the mountains in the middle of Mexico. This species is also found in a similarly broad geographic range in Europe. In the northernmost portions of its range, the mourning cloak (like its close relative the monarch) is migratory and travels seasonally some distance in order to reach more hospitable winter climates. Throughout much of the mourning cloak’s range, however, it is more of a wandering “vagrant” among its wide range of suitable habitats rather than a true migrator.

The distributional range of the mourning cloak is expanding into more and more northern regions. Its is thought that this expansion is yet another observation of the biological consequences of human induced global warming.

The mourning cloak’s wings are irregularly notched into a rough, scalloped edge. The dorsum (back) of its wings are dark in color (purple to maroon) and are edged by an inner line of iridescent, blue spots and an outer border of yellow or creamy white. The venter (underside) of the wings is a dark and striated blackish brown with a pale, gray border. The mourning cloak at rest or in hibernation folds its wings together so that only the drab, camouflaging coloration of the ventral wings is exposed to its potential predators. The name mourning cloak comes from the perceived similarity of the rich, dorsal wing colorations to a traditional cloak worn during a period of bereavement and mourning.

A key characteristic of the taxonomic family to which the mourning cloak belong are the small, somewhat coiled front legs which are typically tucked up “underneath the chin” of the individual. This family of butterflies (the Nymphalidae) is called the “brush-footed” butterflies because of this distinctive first leg pair shape.

Adult mourning cloaks drink from wounds or woodpecker holes in trees. They are especially fond of oak trees and oak sap. Butterflies access these sap holes by walking down the tree, upside down. Adult mourning cloaks also eat rotting fruit, and flower nectar during the summer and are especially fond of the flowers of knapweed and scabiosa. Mourning cloaks, like many butterflies, also swarm muddy puddles and even animal feces from which they gather not only moisture but also vital salts and nutrients.

The mourning cloak mates shortly after emergence from hibernation. Males typically select a sunny perch from which they watch their habitat zones for females. There is a brief courtship, and then the fertilized female lays from 30 to 50 eggs in encircling clusters on the small branches of some selected host tree or shrub species. These eggs hatch into small, black caterpillars that are marked with white speckles and a very dark, continuous dorsal line. On the abdominal end of the dorsal line are two large red spots. The “false eye spots” are thought to serve a distractive coloration role against predators by drawing the attention of the predator to the less vulnerable, abdominal end of the caterpillar.

The caterpillars are voracious eaters and readily consume the leaves of the American elm, aspen, cottonwood, hackberry, paper birch, and several species of willow. The caterpillars grow rapidly and undergo four molts as they move through their larval instars toward the inactive pupal stage. The pupa is encased in a gray chrysalis of silk which hangs from a thread attached to branches or some type of overhanging structure. The metamorphosis into adults takes about 15 days.

The eggs laid in early spring will pupate and emerge as adults by early summer (June or July). These adults may enter a warm-weather inactivity phase (“aestivation”) after which they re-emerge and feed very actively in order to build up hibernational fat reserves. They then hibernate for the winter. An individual experiencing this type of life cycle pattern may live up to 10 months or more! This makes the mourning cloak the longest lived of all butterflies! These June or July emerging adults, though, may also, depending on the climatological conditions or levels of habitat resources, skip the aestivation phase and proceed directly to mating and egg laying. This second brood of eggs, then, hatches into caterpillars which grow, pupate and metamorphose into adults by August or September. This second brood, then, begins to feed and prepare itself for the long winter hibernation. In the northern sections of the mourning cloak’s range one or two of these seasonal broods are common. In the southern sections of the range, however, up to three brood generations are typical.

The eggs of the mourning cloak are very vulnerable to both climatological and biological stresses. Excessive heat or excessive rainfall (or poor placement on a brood branch which exposes the egg cluster to heat or rain) can kill the eggs. Egg predators (especially ants, beetles, beetle larvae, true bugs, and mites) feed extensively on the egg clusters. Parasitic flies and wasps also lay their eggs in the developing butterfly eggs. Further, a newly hatched mourning cloak caterpillar may consume its yet un-hatched siblings! Smaller caterpillars of the mourning cloak are eaten by predaceous insects (assassin bugs, beetles, hornets, and wasps), while larger caterpillars are eaten, very opportunistically, by a variety of reptilian, amphibian, avian, and mammalian predators. Caterpillars may also be parasitized by wasps and flies which lay their eggs on the backs of the larvae.

Adult mourning cloaks may be eaten by a wide range of large insects (dragonflies, preying mantises, and assassin bugs), spiders, and many vertebrate predators (including birds, amphibians, reptiles, and mammals).

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