20 February 2016

Singapore's Long-Tailed Hairstreaks

Singapore's Long-Tailed Hairstreaks
The Magnificent Seven - Part 1

In the 2nd Edition of the Field Guide to the Butterflies of Singapore (2015), the taxonomic classification of the Lycaenidae family has been updated to be consistent with more recent and contemporary literature on this family of butterflies. This group comprises many small but beautiful butterflies that are often coloured a range of iridescent greens, blues and purples. Many are attractively coloured in bright hues whilst others possess tails.

The Lycaenidae in Singapore are represented by six sub-families. These are Curetinae (the Sunbeams), Poritiinae (the Gems), Miletinae (the Harvesters), Aphnaeinae (the Silverlines), Polyommatinae (the Blues) and Theclinae (the Hairstreaks). A common feature of the latter three sub-families is that their wings are "designed" to fool predators into attacking the wrong side of the butterflies. Often sporting tails and adorned with false "eyes" on their hindwings, many species of this sub-families display what is often referred to as "decoy protective strategy".

In particular, the Theclinae, collectively referred to as Hairstreaks, display this decoy characteristic in the majority of the species in the sub-family. In some cases, the decoy is carried to the extreme where the species feature extremely long tails (>10mm long) that appear to be alive as they twirl in the breeze when the butterfly is perched to rest. This blog article (in two parts) introduces our readers to 7 of these long-tailed Hairstreaks found in Singapore.

I have always been amused when our butterfly-crazy friends from Hong Kong visit Singapore, and seeing how happy they were, whenever they encounter one of our long-tailed hairstreaks. Then I realised that amongst the Lycaenidae in Hong Kong, there are no extant long-tailed species there! Perhaps that is why our Hong Kong friends get rather excited when they see these species here in Singapore. We do hope our HK friends would visit us more often to enjoy our butterflies here. 

Part 1 of this blog article showcases 3 of these spectacular long-tailed hairstreaks that can be found in Singapore.

The Branded Imperial (Eooxylides tharis distanti)

A pair of Branded Imperials perched on a young shoot of its caterpillar host plant.  Note the eggs.

A forest-dependent species, the Branded Imperial does not often venture out into urban parks and gardens. They are usually found along the fringes of our forested nature reserves where its preferred caterpillar host plant, Smilax bracteata, a non-native invasive "weed" that is now common in our forests. The signature reddish-orange underside with the unmarked forewing with the hindwing featuring black and white tornal area easily distinguishes the Branded Imperial from the other species in the sub-family.

A Branded Imperial feeding on the secretions of its host plant, Smilax bracteata

The hindwing sports three tails - one long tail at vein 2 of the hindwing and two shorter tails at veins 1a and 3. The upperside is black, with a similar-patterned hindwing tornal area like its underside. The Branded Imperial can be considered common, and is often spotted in shaded areas in our forests. In some areas where they can be found regularly, there are often several individuals seen together.

The butterfly has a "hopping" flight as they flit amongst the shrubbery. They often stop to rest with their wings folded upright. Occasionally, several individuals can be seen together as they feed on the secretions on the young shoots of their host plant. The life history of the Branded Imperial has been recorded and the full documentation can be found here.

The Common Imperial (Cheritra freja friggia)

A Common Imperial puddling at a sandy streambank

The next long-tailed species featured has a wider distribution than the Branded Imperial. The Common Imperial, although a moderately rare species, is more often encountered in urban parks and gardens than within the nature reserves. It can be skittish, and prefers to stay at higher levels at the treetops unless it comes down to feed or lay eggs.

The tails of the Common Imperial are generally longer than those of the Branded Imperial, regularly exceeding 10mm when measured from the tornal area of the hindwing. The male Common Imperial is a deep midnight blue above, whilst the female is brown. The underside is mainly white, with the apical area of the forewing shaded a pale orange. The tornal spots on the hindwing are overlaid with metallic blue-green scaling.

Similar to the Branded Imperial, this species has three tails originating from veins 1a, 2 and 3 of the hindwing, of which the longest is at vein 2. The long, thick white tails have a dark line in the middle, and the ends are often soft and "actively" twirling in the breeze when the butterfly stops to rest. The caterpillar of the Common Imperial feeds on a number of host plants, and the full life history can be found here.

The Fluffy Tit (Zeltus amasa maximinianus)

The third of the long-tailed species featured in this week's article is the moderately common Fluffy Tit. It can be found in urban parks and gardens, as well as in our forested nature reserves. It is usually encountered singly, flitting amongst the shrubbery with its long tails prominently seen trailing behind it as it flies rapidly from leaf to leaf.

A puddling Fluffy Tit

The male of this species is black above, with the basal area of the forewing and a large part of the hindwing coloured a pale azure blue. The female is a dull brown above. The underside is predominantly white, with dark orange areas at the apical areas of both the fore- and hindwings. The hindwing has a prominent black spot at space 2. The hindwing features only two pairs of tails, originating from veins 1b and 2. The longer tail at vein 2 is often twirled in a spiral and appear "softer" throughout its length when compared with the other two species featured in this article.

Male Fluffy Tits are regularly encountered puddling at damp footpaths and stream banks in the nature reserves. It is also sometimes seen feeding on bird droppings. The species is also regularly photographed, feeding on the flowers of the Bandicoot Berry (Leea indica). The life history of the Fluffy Tit has also been recorded and the details can be found here.

And so we are acquainted with 3 of these long-tailed hairstreaks that call Singapore home. In the 2nd part, we will meet 4 other long-tailed species, and one of which features the longest tails amongst all the species in the Theclinae sub-family in Singapore.

Text by Khew SK : Photos by Sunny Chir, Chng CK, Antonio Giudici, Goh LC, Khew SK, Loke PF, Bobby Mun and Anthony Wong