Hobbies Hi! Everything about the picture is fine including the ISO. 500 ISO is well within a useable range for an image, specially for a Sony, which is known for low light performance. Staying lower in ISO where possible is of course always best, but I go all the way to 1600 with no issues, even 3200 under certain conditions.
*edit*hmm i see now your iso may caused overexposure. Unless the highlights are clipped you should be able to lower that through editing.
I had to look up this hornet to see its colour and i agree with the other's comments, less saturation and it would be a great photo, focus looks sharp and capturing it drinking is great timing!
Well done.
BTW: How good is Vietnam? I was in Nha Trang down the south some years back. I miss it very much.