Some time ago mention was made of  someday having a gadget to locate
queens amidst the activity in a hive.
    What comes to mind is to mark the queen with  flourescent paint and use  a
UV light source to make her stand out brightly. There are some blacklight
paints that really light up well and a little shade would enhance the effect.
    When time permits I will try this in my observation hive and report back.
 
Tom in CT