Help to ID Arhopala

[David Chan]

Dear Dr Seow,

Could you please help to ID these 3 Arhopala shot at Upper Seletar Reservoir:

.1 Could this be a Arhopala major major?

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.2 Could this be a Common Disc Oakblue (Arhopala epimuta epiala)?

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.3 Could this be a Sylhet Oakblue (Arhopala silhetensis adorea)?

25247

Thanks in advance.

Best regards,
David Chan

[Psyche]

1 is Arhopala major.

2 & 3 are likely the same species & belong to a group very difficult to ID.
By far the commonest is A. sublustris & it is likely to be this species.

TL Seow: Cheers.

[atronox]

I wonder if the subtle difference in shape of markings is sex-linked. I say so because i have a male sublustris and what i think is most likely a female sublustris taken about 10m apart in the same area and i also noticed the difference in the markings just like these two(i will share these soon). Females seem to have more rounded spots.

Probably the only way to be certain is if someone encounters a mating pair

[Psyche]

I wonder if the subtle difference in shape of markings is sex-linked. I say so because i have a male sublustris and what i think is most likely a female sublustris taken about 10m apart in the same area and i also noticed the difference in the markings just like these two(i will share these soon). Females seem to have more rounded spots.

Probably the only way to be certain is if someone encounters a mating pair

2 is a male as the abdominal end & the short palpi confirmed the sex.
The forewing termen is straighter in the lower 2/3.

3 is a female as indicated by its longer palpi. The abdominal end is obscured.
The forewing termen is also noticeably more convex.

TL Seow: Cheers.
PS. The palpi length can be misleading in photos as this male below by Jonathan shows. The palpi are longish.
What is interesting is that the broken apex appear to show that the black border is widen, only seen in the males of A. selta & phaenops. The others including sublustris have the border a thread.
As the male A. selta have forewing termen rounded (as in the female) this suggest it is probably A. phaenops.
https://c1.staticflickr.com/5/4245/34945642192_0af9c6ddf6_c.jpg

[atronox]

That's interesting. It could be that all the alea subgroup members recorded from Singapore are still extant but the difficulty in identifying them makes their existence hard to confirm

[David Chan]

Dear Dr Seow and Aaron,

Thanks for sharing. Are 2 and 3 the Bright Oakblue (Arhopala sublustris ridleyi) or other subspecies? According the Butterfly Circle 2016 Review, Bright Oakblue (Arhopala sublustris ridleyi) was only ID'ed by you, Dr Seow and added to the butterfly checklist in 2016! Thanks.

Best regards,
David Chan

[Psyche]

As I have stated 2 & 3 are mostly likely to be Arhopala sublustris.


TL Seow: Cheers.

[David Chan]

Thanks, Dr Seow.