Is this a Nacaduba beroe?

Ionolyce helicon.

Ionolyce was formerly considered as a synonym of Nacaduba.

In Singapore the 6Line Blues can be problematic.
With small colonies a single crossing can affect the appearance within a few generatios.
In a large colony the effect will soon be diluted overtime., resulting in only minor variations.

I helicon typically have the FW postdiscal band serially dislocated at every vein, the last spot 3 is shifted in.
Most of the submarginal spots on the HW are V-shaped.
Variations occur.
Typical male.
http://www.butterflycircle.com/check...Line-Blue).jpg
Female is often misIDed as N. beroe.
http://3.bp.blogspot.com/-_tCoAYTboN...e+(female).jpg
http://i153.photobucket.com/albums/s...s/IMG_8894.jpg
http://thaibutterflies.com/wp-conten...nice-icena.jpg

Nacaduba beroe.
FW without the innermost costal spot.
FW postdiscal band typically broken in the middle at vein 5 (FW postdiscal band composed of 4 spots)
FW margin slightly rounded.
Typical male.
https://wanderingbutterflyeffect.fil...f39fce860b.jpg
Male often only retain one costal spot 9.
http://www.butterflycircle.com/check...lt_male_01.jpg
Female is often confused with Ionolyce but lowermost FW postdiscal spot 3 not shifted in.
https://inaturalist-open-data.s3.ama...peg?1616981585
Female below.
https://inaturalist-open-data.s3.ama...jpg?1508597704
Unusual female with blocky submarginal spots. (Have upperside confirmation)
http://www.butterflycircle.com/check...5_1-copy-4.jpg

Nacaduba kurava.
Sometimes the innermost costal spot is missing, confusing it with N. beroe.
The male have distinctly straighter FW margin than the males of the other three species, beroe, calauria & berenice.
FW postdiscal band typically straight. FW submarginal spots 4 & 5 always rounded.
It is unknown for the male to lose 2 costal spots & have only one, as in beroe.
Male without the innermost costal spot. Note the less straight margin, suggesting hybrid.
https://www.inaturalist.org/observations/97532223
Typical males with straight margins.
https://3.bp.blogspot.com/-zQsdA6nHN...Blue-FooJL.JPG
https://www.butterflycircle.com/chec...ue-SunnyC2.JPG
Male with the submarginal spots narrow.
https://images-wixmp-ed30a86b8c4ca88...hlDlXIlou_nWhY
Females have more rounded FW upper submarginal spots.
https://wanderingbutterflyeffect.fil...b787da0005.jpg
https://1.bp.blogspot.com/-Oy9SRsSM0...25281%2529.jpg

N. berenice .
May occasionally lose the innermost costal spot, but have prominent dark striae.
FW postdiscal band typically broken or crooked.
Male.
http://1.bp.blogspot.com/-xFQx2YUBf8...nice+icena.jpg
Typical female.
http://i22.photobucket.com/albums/b3...a/nacuduba.jpg
Unusual female with postdiscal band serially dislocated, but note lowest spot 3 shifted out ,not in.
http://www.butterflycircle.com/check..._female_01.jpg

N. calauria.
FW submarginal spots 4 & 5 more pointed, triangular than the rest.
FW postdiscal bnad usually very straight.
Male left, female right.
http://www.butterflycircle.com/check...enry%20Koh.jpg

TL Seow: Cheers.