Location: Bee Research Laboratory
Project Number: 8042-30500-002-030-I
Project Type: Interagency Reimbursable Agreement
Start Date: Apr 15, 2025
End Date: Sep 30, 2026
Objective:
The overarching goal of the projects described in this agreement is to provide more resources to U.S. beekeepers for controlling Varroa mite populations in honey bee colonies. To meet this goal, there are 2 main objectives:
Objective 1 is to determine whether the wax cell cappings of recapped pupal cells are made up of materials (wax, pollen, propolis) that differ than pristine pupal cells, or that are laid down in a different matrix. Scanning electron microscopy (SEM) images will be taken of the interior and exterior surfaces of the wax cappings from both pristine and recapped pupal cells, and matrix density compared from the images.
Objective 2 is to test whether the wax cappings from recapped pupal cells are more permeable to oxalic acid vapor. A system will be developed to ‘suck’ oxalic acid vapor through wax cappings and measuring the oxalate levels in a solution the passing air is bubbled through on the other side.
Approach:
Objective 1: Wax cappings will be removed from both recapped and pristine pupal cells, the former identified by the lack of silk on the interior surface. Wax cappings will be imaged using a Hitachi TM3030Plus benchtop scanning electron microscope (SEM) attached to a PC having image capture software. This SEM is currently being housed at the Bee Research Lab. Images will be examined and any structural or material differences noted between pristine and recapped wax cappings. If structural differences are observed, images will be analyzed in ImageJ for such features as: (1) distance between wax particles, (2) the presence and size of any pores, and (3) other differences in matrix structure or number of other items, such as pollen grains or propolis. Differences, if any detected, will be analyzed statistically using appropriate methodology.
Objective 2: A system will be devised whereby oxalic acid crystals will be vaporized in a containment chamber (Nalgene or similar, 24 cm3 volume). Wax cappings from either pristine or recapped pupal cells will be attached (via low heat) to the narrow opening (posterior end) of a glass Pasteur pipette and the other, wider diameter end attached to plastic tubing (type). The pipette will be half in and half outside the containment chamber, inserted into the chamber through a hole drilled into the side of the chamber. The tubing will be attached to a low-powered or power controlled vacuum pump located outside the containment chamber. The tubing will pass through a bubbler device (Erlenmeyer flask) with an in-and out port through which the vapor will pass. The water in the bubbler device will contain an acid/base indicator solution (e.g., methyl orange) that indicates an acidic solution. Aliquots of the solution will also be tested for the levels of oxalate (BioLabs colorimetric kit) that are deposited in the solution from the vapor bubbling through it. A control will be included; regular air passing through bubbler and solution tested with oxalate kit.