Featuring the Flos species in Singapore
A Darky Plushblue perches on some flower buds in the shaded forest understorey
The genus Flos, collectively called the Plushblues, showcases some of the most attractive Lycaenidae species with iridescent ultramarine blue uppersides. Unfortunately, all the species rarely sunbathe with their wings fully opened, and one often only gets a glimpse of its attractive blue uppersides. Globally, there are 15 species of Flos recorded, although some researchers have re-classified at least one species of Arhopala under Flos after studies of its early stages and morphology.
A Plain Plushblue feeds on the sweet secretions on the stem of a Rattlebox weed
A Bifid Plushblue perches on a leaf
There are four Flos species extant in Singapore, and only one can be regularly found in urban parks and gardens. The other three are rare, often encountered singly, and forest-dependent species. They usually prefer the shaded understorey of the forested nature reserves of Singapore. The genus is related to the Arhopala and sometimes found in the same heavily-shaded localities.
A Shining Plushblue perches at the edge of a leaf
The Plushblues are generally skittish and easily spooked. They fly quite rapidly and settle on the top surfaces of leaves to perch with their wings folded upright. The underside of the Plushblues is dark purple brown with cryptic bands and spots on both wings. In some of the species, there is a patch of deep red or crimson at the wing bases.
1. The Plain Plushblue (Flos apidanus saturatus)
The Plain Plushblue is the only Flos species that can be found in urban parks and gardens more often than in the forested areas. It is skittish and flies rapidly amongst the shrubbery. It can sometimes be observed feeding on the sap of stems and branches. It stops to rest on tops of leaves with its wings folded upright.
A male Plain Plushblue shows its ultramarine blue uppersides
A Plain Plushblue feeding on the ripened fruits of the Singapore Rhododendron
The male Plain Plushblue is a deep ultramarine on its uppersides, with a thin forewing border. The female is a shining blue with broad black borders on both wings. The underside is a pale purple brown with dark markings across both wings. In pristine individuals, there is often a deep red patch at the base of both wings. The hindwing bears a stubby white-tipped tail at vein 2 and is toothed at veins 1b and 3. There are pale green iridescent scales at the tornal eyespots on the underside of the hindwing.
2. The Bifid Plushblue (Flos diardi capeta)
A Bifid Plushblue feeding on the ripened fruits of the Singapore Rhododendron
The Bifid Plushblue is mainly found in the forested nature reserves of Singapore, and is not seen in urban gardens. Other than the Plain Plushblue, all the other three species are considered rare and usually occur singly in heavily shaded habitats. It is a strong flyer and alert to movements. It is one of the Plushblues of which the female is more regularly observed to sunbathe with wings opened.
A female Bifid Plushblue opens her wings to sunbathe
A Bifid Plushblue shares the sugars from the ripened fruits of the Singapore Rhododendron with an ant
The male Bifid Plushblue is a dark purple-blue above with thin black borders. The female is a paler purple-blue with broad black borders on both the fore- and hindwings. The underside is cryptic in appearance, with dark brown and pale markings. There is a characteristic "V" shaped costal spot that is not connected to the other brown markings on the hindwing that separates this species from the other Plushblues. There is a white-tipped tail at vein 2 of the hindwing and is toothed at veins 1b and 3. The pale green iridescent scales at the tornal area is more extensive that the other species in the genus.
3. The Shining Plushblue (Flos fulgida singhapura)
A Shining Plushblue perches on a leaf in the shaded understorey in the nature reserves
This 3rd Plushblue has the distinction of bearing the word "Singapore" in Malay in its subspecies name. It is a rare forest-dependent species and prefers the heavily-shaded forest understorey in the nature reserves of Singapore. Also another skittish and rapid-flying species, it tends to prefer to fly closer to the ground and stop on the tops of leaves until disturbed.
A newly-eclosed male Shining Plushblue
A newly-eclosed male Shining Plushblue opens his wings to sunbathe
The Shining Plushblue can easily be distinguished from its other cousins in that it has a shorter stumpy tail at vein 2 of the hindwing, and is correspondingly toothed at veins 1b and 3. It is darker in appearance on the underside, and has a dark brown band stretching from costa to base. The males are deep ultramarine blue on the upperside, whilst females are shining blue with broad black borders.
4. The Darky Plushblue (Flos anniella anniella)
A Darky Plushblue perches at the edge of a leaf
The last Plushblue is considered the rarest of the four, and also prefers heavily-shaded forested habitats in the nature reserves of Singapore. It is the least encountered of the four Plushblues and has the same skittish disposition and rapid flight of its other relatives in the genus. It has been bred on various species of Lithocarpus which is a preferred genus on which the other Flos species (except Flos apidanus) feeds.
The Darky Plushblue is tailless, unlike the other 3 species, but the hindwing is toothed at veins 2 and 3. The upperside of the male is a lustrous violet blue with a thin black border. Females are lighter purple with broad black borders on both wings. The underside is mostly dark purple brown with white edging on the darker brown bands. The apical area is distinctly whitened, whilst the iridescent scaling at the tornal area of the hindwing is the least distinct amongst the four species.
Text by Khew SK : Photos by Huang CJ, Khew SK, Loh MY and Horace Tan