any differences you see are just due to lighting differences in these pictures - I only raised this single one in captivity. I know this for certain because we found it in the butterfly exhibit where I used to work, and after raising it for ID I actually had to destroy it due to our strict quarantine restrictions. After reading your comment I even went back and checked the time stamp on these, too - pictures were taken one minute apart.

Given that fact, would you say this is the male or the female, and based on what characteristic?

No problem. I guess the angle and lighting of the second photo is really playing tricks on my eyes. I'll have to take your word on it, because not only does the color appear different, but the subterminal area in the first pic has the diffuse lavender coloration with an indistinct ST line, while the 2nd pic shows a subterminal area with no diffuse lavender and a distinct ST line. Also the median spot in the first pic is a nondescript orbicular shape, while in the 2nd pic it is more reniform with a series of light dashes extending from it. That's one heck of a light trick, but it is possible for lighting & angle to be that deceptive. I've seen the same thing on multiple shots of the same specimen of some of the Plusiinae species.

The sex would be male. In the first photo, the extensive light golden color in the median area along with the diffuse lavender in the subterminal area indicates a male. Females are much darker without the extensive golden median area and without the diffuse lavender ST area (hence my original question of the 2nd photo). You can see the difference between them in the photos on this page and this page.