05 April 2020

Lepidoptera exotica - Part 2

Lepidoptera exotica Pt 2 : The Vagrants
Exotic butterfly species in Singapore

The Indian Red Admiral, a medium elevation species, was spotted in Singapore at Mt Faber Park in 2008

In this 2nd part of exotic (or non-native) butterflies spotted in Singapore, we investigate a handful of species that has mysteriously appeared in Singapore, and then were not seen again, with long intervals between sightings. For some of these species, they were spotted only once and have not appeared since. Although they were added to the list of butterflies found in Singapore, they are considered "vagrants" or "strays" and will not be assessed under the IUCN guidelines in the forthcoming Singapore Red Data Book 3rd Edition.

The Red Helen is a common species in Malaysia, but has been reliably recorded only once in recent years in Singapore

In the animal world, a vagrant is described as "a migratory animal that is off course" or "an animal occurring beyond its normal range; an accidental or nomadic organism." This applies to butterflies that are found straying into an environment where they are normally not found, or beyond their normal known geographical range. They are classified as non-natives or exotics.

A solitary Red Spot Sawtooth was observed in the Central Catchment Nature Reserves in 2014

Vagrancy is characterised by these species' random and unpredictable appearance without any particular explanation or reason. This is opposed to what we refer to as "migrants" or "seasonal migrants" which appear from time to time during certain seasons, and repeatedly appear over a period of several years. Some even have colonies or extend their stay over several generations, before disappearing, and then re-appearing again.

The Great Jay was recorded puddling in the Central Catchment Nature Reserves in 2014

We take a look at some of these "vagrant" or "stray" species that have appeared and reliably recorded by observers over the years.

1) The Red Helen (Papilio helenus helenus)

The Red Helen is a common species in Malaysia, and at times, relatively large congregations can be found at their favourite puddling spots on moist sandy streambanks. Although it is usually associated with forested habitats, it has sometimes also been spotted in some urban parks and gardens in Malaysia.

Some time in 2014, a single Red Helen was photographed at the National University of Singapore area in Kent Ridge. It was feeding at the flowers of Ixora and there was no doubt about the identity of the Red Helen shot that day. How it came to be at that location remains a mystery, as this species has not be recorded in the early authors' checklists before.

A large Swallowtail, the Red Helen superficially resemble the two extant species in Singapore - the Great Helen and Blue Helen. However, the complete series of red ocelli on the marginal area of the underside of the hindwing instantly sets it apart from the other two species.

2) The Great Jay (Graphium eurypylus mecisteus)

Also spotted and photographed in 2014, a solitary Great Jay was spotted within the Central Catchment Nature Reserves. A relatively battered individual was observed puddling at a sandy streambank. This suggests that this wayward species could have made its way into Singapore on its own steam, as the Graphiums are known to be powerful flyers and are likely to travel long distances.

The Great Jay is relatively rarer than many of its related cousins, so it was a surprise that a stray ended up in Singapore. From all our contemporary records, it appears to be the only time this species has been found in Singapore. Fortunately, the photograph of this species was good enough to identify it without a doubt.

The Great Jay is almost indistinguishable from the closely related species. The distinguishing marking on the underside of the hindwing is the red-centred costal bar with is conjoined with the basal band. It is fast-flying and hard to identify if it had not stopped to puddle during the chance encounter back in 2014. Again it is considered another vagrant to Singapore.

3) The Red Spot Sawtooth (Prioneris philonome themana)

Another vagrant that visited Singapore, also in 2014, was the Red Spot Sawtooth. A powerful flyer and skittish butterfly, a Red Spot Sawtooth was spotted feeding at a flowering tree in the nature reserves in Singapore. Again, it stopped long enough for a photo to be taken and identified.

This vagrant species was observed only once in 2014 in Singapore

It was the only encounter of this species on record, and this vagrant has not been reliably seen or photographed again since then. The Red Spot Sawtooth is not uncommon in Malaysia, and I have encountered it many times in several parts of Malaysia, usually puddling along sandy streambanks with many other species of butterflies.

4) The Lesser Albatross (Appias paulina distanti)

Two records of the Lesser Albatross was documented in Singapore.  Both were females and probably strays

Two females of this species, the Lesser Albatross, were spotted. First in 2005 and then again in 2014. The 2nd record was of a dead individual found in the north eastern part of Singapore in an urban residential development. Species of the Pieridae are fast flyers, some of which are known to display migratory tendencies.

However, the chance or opportunistic encounters of this species have fortunately been able to definitively identify that these vagrants visited Singapore. In flight, it may be difficult to separate the Lesser Albatross from many of the local species and unlikely to be identified with great confidence.

A trio of male Lesser Albatrosses puddling in Malaysia

It is a relatively common species in Malaysia, often puddling at sandy streambanks with many other species of Papilionidae and Pieridae. Males tend to congregate in numbers and are locally common. They are often difficult to separate from many of the white and yellow species from the family and not easy to identify when in flight.

5) The Indian Red Admiral (Vanessa indica indica)

A single Indian Red Admiral appeared for 3 days at Mount Faber Park in 2008, and has never been seen again in Singapore since then

In 2008, an individual of the Indian Red Admiral was spotted at Mount Faber Park. This vagrant would have travelled for thousands of miles for it to appear here in Singapore! It has not been recorded in Malaysia and this is the first record of its appearance in Singapore. The nearest known location of this species is in northern Thailand.

A native of India and Indo-China, the Indian Red Admiral is described as a montane species, preferring elevations of above 1,000m ASL. The individual that was observed in Singapore stayed at the same location for 3 days, and sighted by different photographers.

Again, how it ended up in Singapore remains a mystery. The species has not been observed since then. Such is the mystery of nature, and many of our encounters with these vagrants and strays often bewilder us butterfly enthusiasts when we suddenly see a species that is totally new to Singapore.

Text by Khew SK : Photos by Sunny Chir, Khew SK, Loke PF and Mark Wong