Vanessa atalanta, the red admiral or, previously, the red admirable, is a well-characterized, medium-sized butterfly with black wings, red bands, and white spots. It has a wingspan of about . It was first described by Carl Linnaeus in his 1758 10th edition of Systema Naturae. The red admiral is widely distributed across temperate regions of North Africa, the Americas, Europe, Asia, and the Caribbean. It resides in warmer areas, but migrates north in spring and sometimes again in autumn. Typically found in moist woodlands, the red admiral caterpillar's primary host plant is the stinging nettle (Urtica dioica); it can also be found on the false nettle (Boehmeria cylindrica). The adult butterfly drinks from flowering plants like Buddleia and overripe fruit. Red admirals are territorial; females will only mate with males that hold territory. Males with superior flight abilities are more likely to successfully court females. It is known as an unusually calm butterfly, often allowing observation at a very close distance before flying away, also landing on and using humans as perches.
Geographic range
The red admiral is found in temperate regions of North Africa, North and Central America, Europe, Asia, and island regions of Hawaii, and the Caribbean.
Description
The forewing of this butterfly bears on a black ground an oblique vermilion band
and a group of white subapical spots. On the hindwing the larger portion of the distal margin is red, with a row of small black spots and at the anal angle an elongate blue spot. The underside is partly variegated with blue; the forewing is on the whole similar in markings to the upper, while the hindwing is brightly variegated and clouded, bearing black markings, of which those in the cell resemble a figure (on the left wing 18 or 98, on the right 81 or 89); in the middle of the costal area there is a pale patch and in the distal marginal area a row of ocellus-like spots. Sometimes, especially in the female, the red band of the forewing bears a small white spot in the middle.
Biology
In northern Europe, it is one of the last butterflies to be seen before winter sets in, often feeding on the flowers of ivy on sunny days. The red admiral is also known to hibernate, re-emerging individuals showing prominently darker colors than the first brood. The butterfly also flies on sunny winter days, especially in southern Europe.
In North America, the red admiral generally has two broods from March through October. Most of North America must be recolonized each spring by southern migrants, but the species overwinters in south Texas.
Life cycle
Larval and pupal stages
Red admiral larvae measure approximately in length. Their coloration is variable, but they are usually black with white spots and spines. These spines persist into the pupal phase.
In laboratory tests where larvae were reared at various constant temperatures, a difference in pupal period and coloration was found. At higher temperatures, around 32 degrees Celsius (90 °F), the pupal period of the red admiral is 6 days. At 11 to 18 degrees Celsius (51 to 64 °F) this period increases to 18 to 50 days. At even lower temperatures around 7 degrees Celsius (45 °F), the pupal period lasts between 47 and 82 days. The pupae are bright scarlet at high temperatures and black with a smaller scarlet area at low temperatures. This differential coloration at various temperatures may explain why the summer form of the red admiral is brighter and more heavily pigmented than the winter form.
The primary host plant for the red admiral is the stinging nettle (Urtica dioica), but it can also be found on the false nettle (Boehmeria cylindrica), Pennsylvania pellitory (Parietaria) and other species within Urticaceae. Certain plants of the families Compositae and Cannabaceae may also be used as hosts.
Adult stage
The red admiral is identified by its striking black, orange, and white wing pattern. On the dorsal side, its dark wings possess orange bands on the middle of the forewings and the outer edge of the hindwings. The distal ends of the forewings contain white spots. The ventral side of the wings are brown with patches of red, white, and black. The hindwings have a brown marbled pattern. The red admiral has summer and winter morphs. Summer red admirals are larger and more pigmented than winter morphs. The wingspan ranges from .
