Advanced selection program for Authentic Apis mellifera carnica
Breeding for varroa tolerance.
Varroa Sensitive Hygiene (VSH) is a trait in honey bees that enables them to detect and remove bee pupae infested by the parasitic mite Varroa destructor. This behavior serves as a natural and physical check on the varroa mites’ ability to reproduce, resulting in the death of the immature varroa mites present in the cells. VSH bees can recognize and remove mite-infested pupae, leading to a direct and positive impact on lowering the number of mites within the cells. The exact mechanism of how bees recognize the presence of Varroa within the cell is not fully understood, but the VSH trait has been found to be heritable and can be bred into various stocks of honey bees. This trait has proven to be effective at controlling Varroa and holds great promise as a long-term solution to Varroa infestation.
Forcing bee colonies to the very edge of infestation with varroa
to find the colonies with Expression of varroa sensitive hygiene (VSH).
Varroa Sensitive Hygiene (VSH) is a form of hygienic behavior in honey bees that helps them control Varroa mites, which are the primary enemies of honey bee populations. VSH bees have demonstrated resistance to Varroa by actively removing mite-infested brood and having low reproductive success on worker pupae. Researchers at the USDA-ARS Honey Bee Breeding, Genetics and Physiology Lab in Baton Rouge, La., have bred and maintained several stocks of bees with demonstrated resistance to Varroa, one of which is the VSH stock.
The selection of VSH bees involves three main criteria:
Colonies with a low rate of mite population growth over the season.
Colonies that actively removed mite-infested brood.
Colonies in which the mites had low reproductive success on worker / drone pupae.
These selection steps require more time and detailed measurements than are feasible for most beekeepers.
However, new selection assays are being developed to help beekeepers select for this hygienic behavior more efficiently.VSH bees have been shown to have good resistance to Varroa destructor, the primary enemy of honey bee populations.
The hygienic behavior of VSH bees also extends to defense against other pests, such as wax moths and small hive beetles.
By carefully choosing the proper breeding stock, entire local populations of bees can be transformed into mite-destroying armies, helping to improve honey bee health and reduce the need for chemical treatments.
Carnica queens can be tested for hygienic behavior using various methods, such as the freeze-killed-brood (FKB) test, pin-killed brood assay, and unhealthy brood odor (UBO) test. These tests help assess the bees ability to maintain cleanliness and health within the colony.
- Freeze-killed-brood (FKB) test: This is the most commonly used method to test for hygienic behavior. In this test, a frame containing predominantly sealed brood is removed from the colony and placed in a freezer. After thawing, the frame is returned to the colony, and the queen is observed to have removed the unhealthy brood (dead or diseased larvae or pupae).
- Pin-killed brood assay: This test involves introducing artificially killed brood (pinned) into the colony. The colony is then observed for its response to the unhealthy brood, such as removing the pinned brood or showing no reaction.
- Unhealthy brood odor (UBO) test: This field test is performed by spraying a compound that simulates the odor of unhealthy brood onto the colony. Two hours after UBO application, the number of uncapped cells is counted on the test frames. Colonies that successfully remove 95% or more of the dead brood are considered hygienic.
These tests help evaluate the hygienic behavior of Carnica queens and ensure that they are mated with drones that exhibit similar traits. This is important for maintaining the health and genetic diversity of the Carnica population.