oh okay, it looks like you're on the right track, you just need to kick it up a bit more. The specular map is more green than it is yellow. You can also add some noise to it so it'll get that...

this is looking pretty pimp, arran :beer:

any chance we can see the shading network of the fly, I still feel like it's missing the particular way light reacts to it. Take a look at some car...