I chased this butterfly for quite a while before it settled down on a leaf and let me take a photograph! I did not know what it was at the time, but subsequently discovered that it is a species which is endemic to Sulawesi called Hypolimnas diomea Hewitson, 1861. William C. Hewitson being the gentleman who first named it in a book entitled ‘Illustrations of New Species of Exotic Butterflies’. This beautifully illustrated book is available online (1). William Hewitson (1806–1878), was a wealthy collector of beetles and butterflies – and a very fine artist – but he relied mainly on collectors to supply him with specimens and did not visit the tropics as far as I am aware.
These butterflies usually exhibit pronounced sexual dimorphism, a fancy way of saying that the males and females look very different. They are also often mimics – meaning that they look very similar to – milkweed butterflies (Danaids) which are poisonous to birds (or at least they spit them out and learn to avoid preying on them!). The male of this species (H. diomea) has a lovely purple colour on the upper-sides of its wings, rather than the white of the female (shown here). It is only the female which is a mimic in this species (2); probably of taxonomically very different butterflies called Crows, such as Euploea diocletianus and E. latifasciata, which feed on toxic milkweed plants (2).
I came across this butterfly whilst walking along a small road near Highland Resort, about 5 miles from Tomahon (on the road to Kali village).
1) ‘Illustrations of New Species of Exotic Butterflies’, (London: 1851-1866).http://www.biodiversitylibrary.org/item/46120#page/7/mode/1up
2) R. I. VANE-WRIGHT, P. R. ACKERY and R. L. SMILES (1977). The polymorphism, mimicry, and host plant relations of Hypolimnas butterflies. Biological Journal of the Linnean Society 9(3), 285-297.
I am a retired entomologist with a background in quarantine pests and invasive invertebrates. I studied zoology at Imperial College (University of London) and did a PhD on the population dynamics of a cereal aphid (Metopolophium dirhodum) in the UK. I spent 5 years with the British Antarctic Survey studing cold hardiness of Antarctic invertebates and 17 years with the Food and Environment Research Agency. My main interests now are natural history, photography, painting and bird watching.