I'm not too sure what the concentration of the bee haemolymph is going to
tell us (but I'm a clinical biochemist, so I only know about humans😀).
Urine specific gravity gives an indication of the kidney's concentrating
ability and will signal the presence of proteinuria and diabetes.
Serum protein reflects hydration status and whether albumin and
immunoglobulins are significantly abnormal.
Both are very non-specific and of fairly limited value except where they
show up a gross abnormality.  So don't want to dampen the enthusiasm, but
not sure that refractometry is going to be all that informative in bee
diseases. Happy to hear of other views.
Andrew Wootton

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