Acraea Encedon

''Acraea encedon'', the common acraea, white-barred acraea or encedon acraea, is a butterfly of the family Nymphalidae. It is found in sub-Saharan Africa and south-western Arabia. It is one of the species of ''Acraea'' sometimes separated in ''Telchinia''.

Description

The wingspan is , with the female being slightly larger than the male, but otherwise similar in pattern and colour. The apex of the forewing is blackish and divided by a white bar. The rest of the surface of the wings are usually orange with black spots, however paler varieties with a greyish or yellowish base colour are also found.

The butterfly is a polymorphic Müllerian mimic of '' Danaus chrysippus'', which is a highly unusual phenomenon as Müllerian mimicry is almost always monomorphic.

Description in Seitz

''A. encedon'' is a very variable and widely distributed species and appears in many forms but with no definite local races. The black dots are the same in all the forms and are arranged as follows. Fore wing: 1 or 2 basal dots in 1b; a transverse spot in the cell; discal dots in 1b to 6, of which that in 1b is often double and always placed much nearer to the distal margin than the one in 2; in the forms with black apex discal dots 3 to 6 on the upper surface are indistinct against the dark ground-colour. Hindwing: basal dots in (1a), 1b, 1c and 7; 1 or 2 dots in the cell; one dot each in the basal angle of cellules 4 and 5 and discal dots in 1b to 7, of which the one in 3 or 4 is placed nearer to the distal margin than the rest and the one in 2 nearer to the base than that in 1b. The hindwing above has a narrow black or blackish marginal band 1 to 2 mm. in breadth, beneath the streaks on the interneural folds are often red-yellow instead of black. Throughout Africa south of the Sahara and Madagascar.
* ''encedon'' L. (56 e). The apical half of the forewing above blackish with white subapical band composed of 5 or 6 spots in cellules 3-6 (9, 10); ground-colour otherwise red-brown to yellow-brown, beneath somewhat lighter. f. ''infuscata'' Stgr. only differs from encedon in the smoky brown ground-colour.
* f. ''alcippina'' Auriv. 'A. encedana'' Pierre, 1976 morphhas the hindwing in the middle more or less extended white, but otherwise agrees with the type-form.
* f. ''sganzini'' Bdv. (56 e). Markings as in the type-form, but ground-colour straw-yellow to clay-yellow and marginal streaks on the underside of the hindwing usually black; marginal band on the upperside of the hind wing often widened and not sharply defined. Occurs especially on Madagascar.
* f. ''lycia'' F. (56 e) is very similar to f. ''sganzini'', but has a white or whitish ground colour; occasionally the basal half of the fore wing is smoky black-grey on both surfaces and on the upperside only a little lighter than the apical half, ab. ''fumosa'' ab. nov. A specimen with 3 black dots in the cell of the hindwing was named ''ascrepticia'' (!) by Strand. 'A. encedana'' Pierre, 1976 morph
The following forms differ from the preceding in having the apical half of the forewing above not or scarcely darker than the basal half, with distinct black discal dots.
* f. ''necoda'' Hew. (56 e). ow species ''Acraea necoda''">Acraea_necoda.html" ;"title="ow species ''Acraea necoda">ow species ''Acraea necoda''Ground-colour of both wings light grey; forewing with whitish subapical band.
* f. ''daira'' Godm. and Salv [''A. encedana'' Pierre, 1976 morph]. Ground-colour of both wings light brown-yellow; the subapical band of the fore wing absent or only indicated by light yellowish spots.
* f. ''radiata'' Auriv. 'A. encedana'' Pierre, 1976 morphonly differs from ''daira'' in having the extremities of the veins above broadly and triangularly edged with black and the posterior half of the hindwing whitish. Adamaua.

Larva slate-black with yellow lateral line, small white and yellow dorsal spots edged with black, and black spines; head black. Pupa white with the usual black markings. The larva lives on ''Commelina''.

The agreement in colour and markings between the forms of ''Acraea encedon'' and those of the much larger '' Danaus chrysippus'' and '' D. dorippus'' is very remarkable. Compare ''A. encedon'' and ''D. chrysippus'', ''A. alcippina'' and ''D. alcippus'', ''A. daira'' and ''D. dorippus'', ''A. radiata'' and ''D. dorippus'' ab. ''albinus''.

Distribution

There are two subspecies:

*''Acraea encedon encedon'' is found in Africa south of the Sahara and in Madagascar. In South Africa this species is absent from the dry western parts of the country, but common in KwaZulu-Natal coastal areas on the eastern side of the country.
*''Acraea encedon rathjensi'' Le Doux, 1933 is found in south-western Arabia.

Life cycle

The eggs are oval in shape. The larvae feed on ''Commelina'' species, such as '' C. diffusa''. The flight period of the adults is all year, but they are most common from March to May. They are slow fliers, and perch on low-growing vegetation.

In some populations there are two kinds of females, one producing offspring in a normal 1:1 sex ratio, the other producing females only. In other populations the sex ratio is apparently normal. Scientists first believed the distorted sex-ratio was caused by a driving W chromosome. Later research suggests it is caused by cytoplasmic bacteria.

Gallery

Nymphalidae - Acraea encedon.JPG, Mounted specimen from Eritrea
Acraea encedon HotMarina 2012-01-21.jpg, Imago in Benin
C Ilanda FP 13 05 2010.JPG, Larva of the nominate subspecies, KwaZulu-Natal

Taxonomy

It is a member of the ''Acraea encedon'' species group, but see also Pierre & Bernaud, 2014

*''Hyalites'' (group ''encedon'') Henning, 1993, ''Metamorphosis'' 4 (2): 54
*''Acraea'' (''Actinote'') (group ''encedon'' subgroup ''encedon'') Pierre & Bernaud, 2009, Butterflies of the World 31: 2
*''Telchinia'' (''Telchinia'') Henning & Williams, 2010, Metamorphosis 21 (1): 26 Henning, G.A. & Williams, M.C. 2010 Taxonomic notes on the afrotropical taxa of the tribe Acraeini Boisduval, 1833 (Lepidoptera: Nymphalidae: Heliconiinae) ''Metamorphosis'' 21 (1) : 2-38

References

External links

''Die Gross-Schmetterlinge der Erde'' 13: Die Afrikanischen Tagfalter. Plate XIII 56
''e'' as ''encedon'', ''sganzini'' and ''lycia'' ''g'' as ''daira''
Images representing ''Acraea encedon''
at Bold
Images representing ''Acraea encedon encedon'' at BoldAll-female broods and mimetic polymorphism in ''Acraea encedon'' (L.) (Lepidoptera: Acraeidae) in Tanzania

{{Taxonbar, from=Q4674872

encedon
Butterflies of Africa
Butterflies described in 1758
Taxa named by Carl Linnaeus