Nice image Brian You might as well decrease the shadows as they are a bit strong.
IMO the shadow of the insect is nice, but the shadows at the top right corner are a bit distracting.
That looks fine, Brian.
With the first image, I agree that a slight crop of the top and right side to remove those hard shadows would make a more pleasing scene. And I suspect it would take a fraction more highlight brightness. But not the shadows, in fact you might then be able to actually darken the fly shadow a fraction.
Increasing the highlights might make the lighter area to the right of your model a little too bright, but that is where masking on an adjustment layer will come to your aid.
Nicely done.
Hi Brian I use PS , that's why I don't know anything about layers and masks in GIMP and I'm not able to help you. You can start a thread in the 'post processing' part of the forums and ask your questions about GIMP. There might be more people there to answer your specific questions . IMO you lost the lively colours and brightness in your last edit.