The beautiful couple

ID: Fruit piercing moth caterpillar

Came across a couple of caterpillars feeding on some creepers, though both were far off from each other, one of them started slowly moving in towards the tip of the creeper where the other one seemed to be resting and eventually came right on the opposite side of the resting one and stayed there.
The interesting thing about them was that both of them had a different colour, one a bit orange-ish while the other was darker, any reason why the colours where different?

EXIF:
Canon 550D
Canon 100mm macro
F/7.1
Shutterspeed 1/125
ISO 400

Handheld, External flash fired

Location: Nagla trail

The colour difference is quite distinct. I had read that they have different colours in different stages. Experts please confirm. Good details. Thanks for sharing.

Very interesting. Do you have any image with a higher depth of field?