The White Admiral or Red-spotted Purple (Limenitis arthemis) is a polytypic species of North American brush-footed butterfly, common throughout much of the eastern United States. L. a. astyanax has red spots on its underside and the top of the wings are notable for their iridescent blue markings. L. a. arthemis on the other hand has a large white band traversing both the forewings and hindwings.

Distribution map of Limenitis arthemis. The red shows the range of L. a. arthemis; the orange L. a. astyanax; the green L. a. arizonansis; and the yellow shows where the ranges of L. a arthemis and L. a. astyanax overlap.

The Red-spotted Purple is a mimic of the poisonous Pipevine Swallowtail (Battus philenor) and is typically found in open woodlands and along forest edges.

Subspecies

Four subspecies of the butterfly are known:

• Limenitis arthemis arthemis – (American) White Admiral (see also Limenitis camilla)
• Limenitis arthemis rubrofasciata – Western (American) White Admiral, characterised by the absence of blue spots on its inferior wings
• Limenitis arthemis astyanax – Red-spotted Purple or Red-spotted Admiral, no white bands on wings
• Limenitis arthemis arizonensis – Arizona Red-spotted Purple,^[1] no white bands on wings

Description

Both sexes of this species are identical except that the females are slightly larger than the males.^[2] The upper side of L. a. arthemis is mostly blackish-blue with white postmedian bands across both wings. Some individuals have a row of red submarginal spots, while others have this area being blue. The underside of the wings is a blackish color with a broad white postmedian band. The basal area of both wings contains many red spots. The submarginal area may contain a row of red spots and the marginal area having bluish spots. However, sometimes the submarginal and marginal areas are just a reddish-brown color.^[2][3][4]

The upper side of L. a. astyanax is very much like L. a. arthemis except it lacks the broad white bands. The fore wing submarginal area will sometimes have a row of red spots. The hind wings are either a bright iridescent blue or an iridescent bluish-green. The underside of the wings lacks the white band. The basal area has several red spots. It has a row of red submarginal spots and bluish marginal spots.^[2][3]

L. a. arizonensis is indistinguishable from L. a. astyanax except that L. a. arizonensis is found in the southwest and its range does not overlap the range of L. a. astyanax.^[3][5]

Intermediates between L. a. arthemis and L. a. astyanax can occur. L. a. arthemis f. proserpina has faint white bands. L. a. arthemis f. albofaciata has more conspicuous white bands but they are not as broad as the bands are on L. a. arthemis.^[2][4]

Ecology

Preferred host plants: birches, including Betula lenta; Salicaceae, including Salix bebbiana and Populus tremuloides, and Prunus virginiana (Rosaceae).

Also but not as often: Crataegus, Amelanchier, Malus pumila, Prunus pensylvanica and Prunus serotina (Rosaceae), Populus deltoides, P. grandidentata and P. balsamifera (Salicaceae), Alnus rugosa, Betula alleghaniensis and Carpinus caroliniana (Betulaceae), Ulmus americana (Ulmaceae), Tilia americana (Malvaceae) and Fagus grandifolia (Fagaceae).

Adults are diurnal, they fly from the morning until soon after dusk (Fullard & Napoleone 2001).

Etymology

Limenitis (New Latin "of harbours", from Ancient Greek Λιμενιτις (from λιμήν, a harbour, haven) - an epithet of Artemis, goddess of the hunt and the wild. arthemis, from Artemis.^[6]

Image gallery

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  Side view of Limenitis arthemis astyanax, Hot Springs National Park, Arkansas, USA.

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  Back view of Limenitis arthemis astyanax, Hot Springs National Park, Arkansas, USA.

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  White Admiral in southern Maine.

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  Red-spotted Purple (Limenitis arthemis astyanax), Baltimore, Maryland, USA.

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  Two White Admiral butterflies (Limenitis arthemis arthemis), New Brunswick, Canada.

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  White Admiral in Saskatoon, Saskatchewan, Canada.

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  Red-spotted Purple (Limenitis arthemis astyanax), York, Pennsylvania, USA.

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  Limenitis arthemis arthemis, dorsal, Ottawa, Ontario

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  Limenitis arthemis arthemis, ventral, Ottawa, Ontario

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  Caterpillar

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  Limenitis arthemis arthemis, Quebec

In popular culture

The poem Unconscious came a beauty by May Swenson mentions the "Red-spotted purple" (or the similar looking Mourning cloak) - a butterfly that makes her pause in her writing. The poem is also a word-picture or iconograph, where the lines are laid out to look like a butterfly.

The White Admiral (Limenitis arthemis arthemis) is, since a poll in October 1998, the (unofficial) insect emblem of the province of Quebec, Canada. (See Quebec symbols and emblems for further details). It is the only sub-species of Limenitis arthemis present in Quebec.

References

• Darby, Gene (1958). What is a Butterfly. Chicago: Benefic Press. p. 37. 
• Fullard, James H. & Napoleone, Nadia (2001): Diel flight periodicity and the evolution of auditory defences in the Macrolepidoptera. Animal Behaviour 62(2): 349–368. doi:10.1006/anbe.2001.1753 PDF fulltext
• Handfield, Louis (1999): Papillons du Québec. Broquet. ISBN 2-89000-486-4

Footnotes