07 January 2017

Butterfly of the Month - January 2017

Butterfly of the Month - January 2017
The Common Yeoman (Cirrochroa tyche rotundata)

A male Common Yeoman basking in the sun with its wings opened flat

As the last strains of Auld Lang Syne fade away, and the raucous "Happy New Years" subside amongst the crowds of new year gatherings all around the world, we are now in the year 2017. For many of us, it's back to work/school or the usual grind, as we face the coming year with anticipation (and good measure of trepidation), considering the uncertainty in the world that we live in today.

A female Common Yeoman

For the optimists, it's just another year ahead, where many opportunities abound. The Singapore GDP grew an unexpected 1.8% for 2016, despite talk that the economy had slid into recession. Perhaps there is indeed some optimism ahead, but economists continue their predictions of a slowdown and 'strong headwinds' that will have adverse effects on Singapore this year.

The world is also watching what happens in the US, when President Donald Trump steps into the White House later this month. Of interest to those of us over on this side of the globe would be the changes in US foreign policy and how it would affect ASEAN and the rest of Asia. Already, Singapore was beginning to feel like a caterpillar beneath two stomping pachyderms towards the end of last year. Who knows what 2017 will be like?

For the first month of this year, we feature a bright coloured butterfly to reflect the optimism that we should start the year with. Our Butterfly of the Month is the Common Yeoman. This species is a new discovery in Singapore, having been first observed in June 2015. How this fulvous orange butterfly suddenly appeared in Singapore is still a mystery. The small colony of the Common Yeoman continued to be seen for a few months and there were several generations observed.

The Common Yeoman is orange on the upperside, with a thin black distal margin and black sinuate marginal and sub-marginal lines. The underside is pale silvery white with silvery transverse band on both wings. The band is narrow and roughly uniform in width. This characteristic band distinguishes this species from other similar-looking and related species in the genus.

The species is not uncommon in Malaysia, and has been observed as close by as the Panti Bird Sanctuary, near Kota Tinggi in Johor - some 60km drive from Woodlands Checkpoint in Singapore. It is also likely to be in the forested areas nearer to the Causeway and may have migrated over to Singapore in recent times.

The Common Yeoman is active and often always on the move, fluttering restlessly at treetops, amongst shrubbery and occasionally coming down to feed on flowering plants or to puddle at damp spots along footpaths and leaf litter. The behaviour of the Common Yeoman is reminiscent of the Leopard (Phalantha phalanta phalanta).

A Common Yeoman takes cover under a leaf with its wings folded upright

Occasionally, when alarmed, the Common Yeoman also displays a similar behaviour to its closely related cousin, the Banded Yeoman (Cirrochroa orissa orissa), in that it will fly and hide on the underside of a leaf with its wings folded upright.

A male Common Yeoman puddling

The full life history of this species has been documented in Singapore. Its host plant is Hydnocarpus castanea and alternatively, Hydnocarpus alpina both from the family Achariaceae. The host plants are cultivated selectively at our urban parks and the Common Yeoman should be looked out for when they visit these plants to oviposit. Perhaps NParks may consider cultivating the two host plants more widely in our parks and even nature reserves to attract and sustain this species in Singapore.

Text by Khew SK : Photos by Khew SK, Jonathan Soong and Horace Tan