The first one is Ionolyce helicon. The wing shape and the post-discal striae on the forewing in space CuA1 give it away. I've shot many of these hoping that one of them would turn out to be N. beroe. N. beroe seems rare- i've not seen one yet.
There are several species recorded from Singapore in the past.
Nacaduba 4-lines with the dark striae absent or weak.
A. HW with the marginal & submarginal spots wider apart. 1. N. sanaya & 2 .pendleburyi.
B. HW with the marginal & submarginal spots near to each other 3. N. subperusia & 4. N. hermus.
I've been shooting lots of alea-subgroup Arhopala recently and several of them have had much wider fw post-discal bands. This one male which I tracked gave me a glimpse of the upperside, showing the fw border increasing in width towards the apex. The fw termen is also revealed to be evenly curved from the upperside.
To cut to the chase, I think this is Arhopala selta.
Last edited by Banded Yeoman; 10-Jul-2019 at 10:16 AM.
The border is definitely increasing in width but i'm not sure if this is wide enough for selta. Unfortunately this is a very poorly known group and there's very little information online and i don't have my references with me, so i'll let Dr Seow have a say
You have very clear shots of both surfaces ,so there is no ambiguity.
Thus it meet all the criteria.
1. UpF border increases towards the apex.
2. HW postdiscal spot 6 overlaps the cellend bar by half.
3. FW termen somewhat rounded.
Whether the FW postdiscal band is always relatively wide is hard to say.
Perhaps A. phaenops also occur in Singapore.
In the thread below, the male have a straight termen , the UpF border appears to be broad at the apex, & HW spot 6 barely overlaps the cellend bar.
Only the males of selta & phaenops have the UpF border increas at the apex.
All other males have the FW border a thread throughout. http://www.butterflycircle.com/showt...rhopala-for-ID!
Aaron, Dr Seow, thanks for confirming that for me.
I based my judgement on the key and plates from the marvellous Butterflies of Borneo, Vol.2 No.1 Lycaenidae （1991） by Yasuo Seki, Yusuke Takanami and Kazuhisa Otsuka. The male A. selta is a strong match to the one I shot.
Regarding the suspected A. phaenops that I shot a few years back, I'll leave as A. sublustris . Close examination of the hindwing border (which shows in one of the shots) reveals that it is a thread, only increasing in width below vein 2. This is typical of A. sublustris. In A. phaenops the border will be consistently thicker. There is a chance that the forewing border for my suspected A. phaenops is an illusion due to the odd chip off the wing, casting a shadow.
I have shot a number of typical A. sublustris and the borders are always a thread, with a bright blue upperside. I may post these later.
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