an experiment, enhancing the propolis envelope

Seeley's new book, The Lives of Bees, describes propolis research by Marla Spivak and others at the University of Minnesota.   In the wild, honey bees coat their tree cavity surfaces with propolis - with an especially thick layer of propolis at their nest entrance. In experiments with man-made 5 frame hives, hives with a propolis envelope have better health:

• lowered immune response expression
• less bacterial growth in brood food
• lower number of chalk brood mummies
• reduced severity of American Foulbrood

Having seen the experiment where plastic propolis trap material (with 7 mm gaps) is stapled to hive box walls, I'm inspired to modify my own hive.   Shown are medium box walls where bees added a thin layer of red propolis from previous years.  I created side-by-side patches of shallow 1/8 inch (3.2 mm) and 1/4 inch (6.4 mm) gaps to box walls using a Dremel tool.   Whether bees create a thicker layer of propolis is left to be seen during this 2020 season - stay tuned.