20 February 2010

Two Skips and a Growl

Two Skips and a Growl
Updating the Singapore Butterfly Checklist to 294

The addition of these three species - two Hesperiidae and one Danainae to the Singapore Butterfly Checklist has been long overdue. The Checklist, which now stands at 294, dates back to the early 90's when Steven Neo first started his surveys with the National Parks Board. Having taking over the baton from the late 90's I have kept intact, all the species that Steven had earlier recorded - some of which have not been seen since the early 90's.

The addition of the two Skippers and a Tiger doesn't bring the checklist to a close. In fact, as ButterflyCircle has more and more 'eyes and ears' on the ground, it is likely that there will be more discoveries and re-discoveries in the coming years, particularly in the Lycaenidae and Hesperiidae families where there are numerous lookalike species.

The limitation of field observations and photographs taken of either the upper or underside of a lookalike species cannot be understated. Up to a certain extent, field identifications are possible, but where close scrutiny of both the uppersides and undersides and also males and females of a species to confirm the species' identification with a higher level of confidence, the collection of voucher specimens become necessary. Without the requisite collecting permits from the authorities, the addition of species that are hitherto not recorded would be impossible.

The family Hesperiidae comprises rather unattractive and moth-like species and often under-researched as far as butterflies are concerned. This may be why the majority of new species discovered fall into this family - both locally and also globally.

The Large Dart (Potanthus serina)

The first re-discovery is from the genus Potanthus. Comprising a genus that features a total of 13 species in the Malaysian butterfly fauna, of which 5 species have been recorded in the past, we have only documented the Lesser Dart (Potanthus omaha omaha) as the only extant species in Singapore.

We now record the existance of the Large Dart (Potanthus serina) with a high level of confidence, having bred the entire life history of this species, as well as scrutinised several specimens - both males and females from various locations. The early stages will be featured in an upcoming article in this blog.

The Large Dart was named Potanthus hetaerus serina in early references but recently updated to its current name of Potanthus serina. It is the largest of the species in the genus, attaining a wingspan of up to 32mm. A characteristic feature of this species is that the three subapical spots are separate from the spots in spaces 4 and 5, and are not completely dislocated at vein 6 where the spots in spaces 5 and 6 overlap and not completely detached . The veins are dark dusted on the upperside of the hindwings. On the hindwing beneath, the ochreous scaling is orange-tinged.

The species frequents grassy areas and has been found in the nature reserves as well as in mangrove areas. Like most of its other close relatives in the genus, it is a rapid flyer. It is often observed in shaded areas in the afternoons, with its wings folded upright. In the early morning hours, one can observe it displaying the usual skipper pose, with the forewings held at an angle whilst the hindwings are opened flat.

The Common Palm Dart (Telicota colon stinga)

The record of this species, one of three in this genus. Records of this genus show that there are six species in the Malaysian and Singapore region, of which three have been recorded. With the confirmation of this species, all three are now extant in Singapore.

The presence of this species has been overlooked all this time, primarily due to field observations of the lookalikes of the genus Telicota. The other two species, T. augias and T. besta bina have been recorded earlier with voucher specimens. This latest re-discovery would not have been possible without breeding the early stages as well as dissection of the genitalia of a bred male specimen by ButterflyCircle member Chan Soon Chye. Having the benefit of comparing the details of the genitalia with the reference diagrams in the Butterflies of Singapore by Corbet & Pendlebury, and the descriptions of the species, the Common Palm Dart is now re-instated to the Singapore Checklist.

The Common Palm Dart is a relataively large skipper, attaining a wingspan of up to 36mm. The yellow colour of the post-discal band on the forewing is continued along the veins towards the termen. The bluish-grey stigma on the forewing in the male is more conspicuous that in the other species.

It is another rapid flyer and males are often seen 'dogfighting' in the early hours of the morning, and then resting on leaves and grass blades in the usual Skipper pose.

Yellow Glassy Tiger (Parantica aspasia aspasia)

Sightings of this Danainae have been recorded in the past, but it was uncertain as to whether the individuals sighted were actually imported products of human agency or free-ranging immigrants straying into Singapore during the NE monsoon season when the north-easterly winds tended to bring species from the southern part of the Malay Peninsula into Singapore.

Another recent sighting of a female at Hort Park, feeding on the flowers of the Indian Heliotrope (Heliotropium indicum) prompted us to record this species as a re-discovery. Though documented in the early authors' checklists, this species appears to be more of a seasonal migrant rather than an extant species in Singapore. It is still a mystery why this species no longer appears with regularity in Singapore, like its common cousins, the Dark Glassy Tiger (Parantica agleoides agleoides) and the Blue Glassy Tiger (Ideopsis vulgaris macrina).

A female Yellow Glassy Tiger shot recently at the Hort Park

Perhaps the species' preferred host plant is no longer available? Or the habitats are unconducive for its permanent re-establishment in the Singapore environment? As it is a rather common species in the Malaysian forests, further research may help us reach a conclusion as to why this species is not able to stay on permanently. This is one of the species that could be the subject of a re-introduction programme together with NParks after the host plants are cultivated at strategic habitats around the island. The Life History of the Yellow Glassy Tiger, recorded by ButterflyCircle member LC Goh in Kuala Lumpur can be found here.

With these three additions, the Singapore Butterfly Checklist now stands at 294 species. The checklist is by no means complete, as new additions are to be expected as more and new information is available on our butterfly species. There have been many 'extinctions' but also many new discoveries of species that were not on the early authors' original checklists.

As we move into a new decade in 2010 and also celebrate the International Year of Biodiversity, let us look forward to more additions to the Singapore butterfly fauna and work to conserve the species that have already made Singapore home.

Text by Khew SK ; Photos by Khew SK, Bobby Mun, Horace Tan, Anthony Wong & Mark Wong

References :
  • The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition 1992, Malayan Nature Society.
  • Butterflies of West Malaysia and Singapore, W. A. Fleming, 2nd Edition 1983, Longman Press
  • The Malayan Nature Journal, Vol 59, Part 1, Oct 2006, Malaysian Nature Society