|Table of Contents|
Tawny coster Acraea terpsicore. Photo by Green Baron Pro on Flickr. Creative Commons.
. The rapid spreading Tawny Coster is suspected to be a potential invasive species. Please visit Section 1.1 The Journey of the Tawny Coster and Section 2.7 Conservation Status for more information regarding its spread and potential invasive status.
Glasswing Butterfly Greta oto from family Nymphalidae standing on four legs. Photo by William Warby from Flickr. Creative Commons.
. From the figure below, it can be observed that Tawny Coster has been travelling down South, from Sri Lanka and India to the further south South-East Asia and then Australia. Please visit Section 2.6 Global Distribution for its distribution worldwide.
Distribution of tawny coster in South-East Asia and north-western Australia, showing known locations (black circles). Years of detection (first recordings) are indicated for each country. Image adapted from journal by Braby et al 2014.
Local Distribution of tawny coster.
The genus name Acraea is derived from the ancient Greek word acraeus which means at high latitude
|Oviposition (Depositing of eggs)|
Female tawny coster oviposits on the underside of stinking passionflower.
The eggs are yellow in colour and olive-shaped.
The infant caterpillar consumes the upper portion of the egg shell while hatching.
The body segments develop a bright yellowish brown coloration. This instar lasts about 2 to 2.5 days.
Body turns orangy brown. This instar lasts 2 to 3 days.
Similar physical appearance as 2nd instar. This instar lasts 2 to 3 days.
Similar physical appearance as 3rd instar, except for paler coloration in first two segments. This instar lasts 3 to 5 days.
Little change to physical appearance except for the increase in size. This instar lasts 5 to 7 days.
|6th and final instar|
Head turning almost fully orange. This instar lasts between 9 to 13 days.
Pupation takes place on the underside of the stem. White-based pupa has black narrow bands running lengthwise. This lasts for 5 days before the pupa matures and turns salmon orange.
Eclosion takes place one day after the pupa turns salmon orange.
"What is Sexual Dimorphism?", Klappenbach L. About, 04 Jun 2015. URL: http://animals.about.com/od/zoology12/f/sexualdimorphis.htm(Acessed on 19 Nov 2016)
The wings of the male are deep salmon orange (left) while the wings of the female are pale tawny yellow (right). Photo by paper from Braby et al. Permission pending.
So... does it mean that the fate of the paternity solely depends on the female's choice? NO!!
Sphragis on the female copulatory opening. Photo and annotation by Horace Tan. Permission obtained (left). Dorsal view of sphragis. Annotations by Sandy Tan. Photo from paper by Braby et al (middle) Permission pending. Lateral view of sphragis. Photo from paper by Braby et al (right). Permission pending.
With females being choosy with their mates, there exists high male-male competition as they compete for access to mating. Thus males have also evolved adaptations to increase males' chance of reproductive success
. Locally in Singapore, the relative abundance of P. foetidacould be an explanation behind the rapid spread of tawny coster in Singapore. With an abundance of the host plant, the population of tawny coster is able to flourish as well.
A personal observation at Coney Island: There is an increase in spread of stinking passionflower (major host plant for tawny coster) in Coney Island to an extent that it seems to be growing at areas where Cynanchum ovalifolium Akar Bano was usually found to be present at. As a result, sightings of Danaus genutia genutiaCommon Tiger seemed to have lessened. Could it be that the spread of stinking passionflower could have indirectly resulted in the displacement of common tiger butterfly?
Common tiger (left). Photo by Sek Keung Lo from Flickr. Creative Commons. Akar bano (right) Photo by Horace Tan. Permission obtained.
3.2 Original Linnaean Description
Original Linnaean description in Systema Naturae (1758).
|Danaus chrysippus chrysippus|
|Danaus genutia genutia|
As Papilio terpsicore Linnaeus, 1758 is the oldest available name, it is therefore a senior synonym of Papilio violae Fabricius, 1775.
Specimen of terpsicore in Linnean Society of London (left) Image from Linnean Society of London. Specimen of violae in Zoological Museum, Copenhagen (right) Image from paper by Honey and Scoble 2001
Butterfly circle, a butterfly enthusiast group in Singapore have been using A. violae to describe Tawny Coster but since 2015, the scientific name of this species has been adopted as A. terpsicore.
Adopting A. terpsicore as scientific name. Image taken from Butterfly Circle
Silva-Brandao KL, Wahlberg N, Francini RB, Azeredo-Espin AML, Brown Jr. KSB, Palauch M, Lees DC & Freitas AVL (2008) Phylogenetic relationships of butterflies of the tribe Acraeini. Molecular Phylogenetics and Evolution, 46, 515-531.
Division of subfamily Heliconiinae into 4 tribes. Image from Nymphalidae.net
Wahlberg N, Braby MF, Brower AVZ, Rienk de Jong, Lee M, Nylin S, Pierce NE, Sperling FAH, Vila R, Warren AD & Zakharov E (2005) Synergistic effects of combining morphological and molecular data in resolving the phylogeny of butterflies and skippers. Proceedings of the Royal Society of London B, 272, 1577-1586.
Phylogenetic analyses of the combined molecular and morphological datasets. (a) Single most parsimonous tree. Numbers above the branches are Bootstrap value for the node to the right of the numbers and italicized numbers below branches are node numbers. (b) Tree resulting from Bayesian analysis using mixed models. Number below branches are posterior probabilities for the node to the right of each number. Colour codes represent families as follows: pink, Hedylidae; red, Hesperiidae; green, Papilionidae; yellow, Pieridae; purple, Riodinidae; blue, Lycaenidae; orange, Nymphalidae. Annotation from Sandy Tan. Screenshot taken from study by Wahlberg et al.