30 April 2024

Butterfly of the Month - April 2024

Butterfly of the Month - April 2024
The Brown Awl (Badamia exclamationis)

It has been a very hot hot April, with temperatures in Singapore soaring in the high 30's. All over Asia, temperatures are at an unprecedented high, and we are not even in the summer months yet! If this is not climate change, then I don't know what is. Historical highs are being recorded year after year and it is quite widely acknowledged by butterfly watchers and enthusiasts that butterfly populations are down in many parts of Asia, compared to a decade ago.

This month, our feature butterfly is the unremarkable Brown Awl (Badamia exclamationis). This is a skipper from the sub-family Coeliadinae and the only representative of its genus in the region. It is a relatively large butterfly and is a fast-flyer like most Hesperiidae species. I've always been intrigued by the latin species name of this Skipper. It's as though the scientist who first described it screamed out loud when he first discovered this butterfly!

The Brown Awl is moderately rare in Singapore, usually observed singly in the early hours of the morning. It has also been observed to puddle occasionally, but where it is encountered, it is more often seen feeding on moisture off damp rocks, stone walls and timber structures in the cooler morning air. There have been few records of the Brown Awl feeding on flowers.

The species is more often encountered in the forested nature reserves than in urban parks and gardens, although it is widely distributed across Singapore and found in various habitats where its caterpillar host plants, Combretum sundaicum and Terminalia calamansanai (both from the Combretaceae family) are found. Where they are observed, they are usually encountered singly.

A Brown Awl perched on a damp rock after feeding off moisture from the rock
A Brown Awl feeding on the flower of the String Bush at Tampines Eco Green

The wings of the Brown Awl are very elongated and the hindwing is caudate at vein 1b, and strongly excavate between veins 1b and 2. Above, the wings are dark brown with greyish green scaling at the wing bases. The female has prominent and elongated hyaline streaks in spaces 1b, 2 and 3, and the cell in the forewing. In contrast, these streaks in the male are rather small and subdued.

A partial upperside view of a male Brown Awl

On the undersides, both sexes are pale greyish brown and largely unmarked. There is a small yellowish sub-tornal spot in space 1b of the hindwing, which usually goes unnoticed as the hindwings typically fold up at the dorsal area. The prominent veins on the underside gives the butterfly a streaked-like appearance. The abdomen of the butterfly is prominently yellow-banded.

Under leaf behaviour of the Brown Awl where it clings on to the underside of a leaf to rest

The Brown Awl occurs from Sri Lanka, India, China through the Malay Peninsula and Singapore to New Guinea, Australia and as far east as Samoa. In Singapore, it is usually encountered feeding at damp rocks or at flowering plants (uncommonly). It has a habit of perching on the undersides of foliage with its wings folded upright and often adopts this position when it is disturbed and flies off to hide under a leaf.

Text by Khew SK : Photos by Khew SK, Koh CH, Dr Lee PC, Billy Oh, Jonathan Soong and Horace Tan