Acraea terpsicore cover page.jpg

A group of Acraea terpsicore caterpillars feeding on Passiflora edulis (top left). A. terpsicore caterpillars (top right). Adult A. terpsicore (bottom left). Photos by Horace Tan, permission obtained.


1 Introduction


The Tawny Coster, Acraea terpsicore, is a butterfly of largest family of butterflies Nymphalidae. Butterflies of family Nymphalidae are commonly known as brush-footed butterflies as most species have brush-like hair on the fore legs. This species occurs naturally on peninsular India and Sri Lanka but it has spread to South-East Asia during the past three decades [1]. Locally, it was first discovered at an open wasteland in the north-eastern part of Singapore in September 2006 and since then, it has spread to many other parts of Singapore, now a commonly seen butterfly all over Singapore, including the offshore island of Pulau Ubin [2].

1.1 Etymology


The genus name Acraea is derived from the ancient Greek word acraeus
The species name terpsicore is derived from the Greek word Terpsichorē, which refers to the Greek Muse of dancing and choral song, likely a reference to the lazy sailing dance-like fluttering of the Tawny Coster [3]. The common name Tawny refers to the tawny coloured wings of the Tawny Coster accompanied with black spots on them.




2 Biology


Tawny Coster is a medium-sized butterfly with the wingspan of an adult butterfly ranging from 53mm to 64mm. The upperside is deep orange with narrow, black outer borders and black wing spots. The black thorax and black hindwing border are spotted white. The underside is paler with markings more prominent [4].

2.1 Host Plants


The local caterpillar host plants are mainly from family Passifloraceae. They include the following:
Scientific Names
Common Names
Passiflora foetida
Stinking passionflower, love-in-a-mist
Passiflora suberosa
Corky-stemmed passion flower
Passiflora edulis
Passion fruit
Tunera ulmifolia
Yellow Alder
Passiflora foetida in particular is a common weed in our wastelands and cleared areas, thus it may explain the rapid spread of Tawny Coster across the island, after it first appeared in Singapore since 2006. However, P. foetida is a fast-growing plant, able to smother other plants within a short period of time as it
It is known to be invasive in

Will Tawny Coster be a potentially invasive species in Singapore?



2.2 Life Cycle



Life cycle.jpg
Life cycle of Tawny Coster. Individual photos by Horace Tan, permission obtained.

The Tawny Coster lays its short olive-shaped eggs in a large cluster on the undersides of leaves of the host plant. After hatching, the caterpillar feeds gregariously on the leaves of the host plant. The caterpillar goes through six instars before reaching the pupa stage. Pupation takes place on the underside of a stem of the host plant. The pupa has white ground colour and several black narrow bands or stripes running lengthwise. It has short, pale golden-brown processes embedded in the bands running dorso-laterally, laterally and ventrally. The pupa is suspended vertically via a cremastral attachment to the plant [5].


A Tawny Coster adult butterfly emerges from its pupal case. Original video from YouTube by Horace Tan



2.3 Sexual Dimorphism


Male and Female.jpg
The wings of the male are deep salmon orange (bottom) while the wings of the female are pale tawny yellow (top).

2.4 Defense


2.4.1 Aposematism




The pupa boldly marked with aposmatic colors, advertising the fact that this is an unwholesome object if eaten. It is white with thick black lines, spots and markings in red and orange. The pupa hangs freely from the support without the aid of a band. The pupa is 17 mm (0.67 in) long.


3.2 Predators

3.3 Mating Plugs

4 Taxonomy and Systematics


4.2 Synonyms


Acraea terpsicore or Acraea violae?

Acraea terpsicore (Linnaeus, 1758)
Acraea violae (Fabricius, 1793)

A. terpsicore was described as Papilio terpsicore by Linnaeus in 1758, which was held to be the senior synonym of A. serena and was described by Fabricius as P. serena in 1775. Thus A. terpsicore was commonly used for the African species A. serena. However, Linnaeus had actually described an Indian species - Tawny Coster instead of the African species. Fabricius believed this Indian species was new to science and described it again as P. violae in 1793. Consequently the Tawny Coster has been long known as A. violae.

Until now, there have been uncertainties regarding the scientific names of the Tawny Coster. Some online pages refer Tawny Coster to Acraea violae while others refer it as Acraea terpsicore.

Retrieved from a forum in the website of Butterfly circle, a butterfly enthusiast group in Singapore dated August 15, 2013:

Acraea terpsicore or violae butterflycircle forum.jpg

Update on 2015: The scientific name of this species has been adopted as A. terpsicore by several authors henceforth, and updated accordingly.

Butterflies of India

No subspecies are listed under this species. There has been long-standing confusion among taxonomists as to whether the correct name for the Tawny Coster is Acraea terpsicore Linnaeus, 1758 or Acraea violae Fabricius, 1775/1793. Several authors had pointed out that they had failed to locate the type of Papilio terpsicore Linnaeus, 1758, and that that name had been erroneously used for several species in Africa and Asia, so terpsicore Linnaeus, 1758 was not defined properly. As a result, these authors had concluded that Papilio violae Fabricius, 1775/1793 was probably the valid name. However, several key papers had clarified this issue, and shown that the type of terpsicore Linnaeus, 1758, collected from the Chennai area (erstwhile Madras) in SE India, existed in the collections of the Linnean Society of London and identified as such (le Doux 1922, 1928; Pierre and Bernaud 1997). Following this, until evidence is provided to the contrary, it appears that Acraea terpsicore Linnaeus, 1758 should be used as a valid name for this species.



References

1. Braby MF, Bertelsmeier C, Sanderson C, Thistleton BM (2014). Spatial Distribution and range expansion of the Tawny Coster butterfly, Acraea terpsicore (Linnaeus, 1758) (Lepidoptera: Nymphalidae), in South-East Asia and Australia. Insect Conservation and Diversity, 7, 132-143.
2. http://butterflycircle.blogspot.sg/2008/03/voyage-of-tawny-coster.html
3. http://www.merriam-webster.com/dictionary/Terpsichore
4. A Naturalist's Guide to the Butterflies of Peninsular Malaysia, Singapore and Thailand. Laurence G. Kirton
5. Caterpillars of Singapore's Butterflies. Horace Tan & Khew Sin Khoon