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Genetic Stock

Overview

With honey bees, it is relatively easy and quick to change their genetics. Once the apiarist has replaced the colony's queen, her progeny will be the residents of the colony in 6 weeks.

There are research efforts underway to produce queens with key genetic traits such as:

• disease resistance,
• nice temperament,
• high levels of honey production, and
• over-wintering capabilities.

There is no queen yet which offers the best of all these options, but there are some options as outlined below.

#################### Minnesota Hygienic

Minnesota Hygienic

Originally developed to help colonies resist and recover from American Foul Brood and Chalkbrood, the Minnesota Hygienic line of bees was developed by Dr. Marla Spivak in 1993. Colonies that display 95 to 100% hygienic behaviour are used as breeder colonies. This stock is now also advertised as helping reduce Varroa mites. Tests show that this line is not quite as effective at lowering mite population as VSH lines are, but it is more effective than non-hygienic stocks.

#################### Purdue Ankle Biters

Purdue Ankle Biters

Greg Hunt at Purdue University developed the Ankle Biter bee stock in 2007. While hygienic behaviour bees target Varroa mites reproducing in the brood cells, Purdue Ankle Biter bees target 'Varroa'' phoretic mites. Purdue Ankle Biter bees injure the mites by biting off parts of their body and removing their legs (hence the term “ankle biter”). Insects do not have an immune system which can heal their body from such an injury, so chewed mites typically die from their injuries.

This option shows great promise in helping a colony reduce its chances of dying from 'Varroa'' mites. In a blind study, Purdue distributed 102 queens to 39 beekeepers in 2014. Half of the queens were Purdue Ankle Biters, while the other half were some other commercial stock. Beekeepers received one queen of each and were asked to keep records on colony survival and honey production. The beekeepers did not know which queen was an Ankle Biter and which was not.

The beekeepers introduced the new queens in the summer of 2014, and by March 2015,

• More colonies survived the Winter:
  • 55% of Ankle Biter colonies were still alive,
  • 22% of the non-Ankle Biter colonies were.
• Honey production was higher in Ankle Biter colonies:
  • Ankle Biters produced an average of 52 pounds per colony,
  • non-Ankle Biters produced 11 pounds per colony.

#################### Russian

Russian

In 1997, the USDA-ARS program imported Russian bees and has continued breeding them for Varroa resistance. These bees have been naturally living with Varroa mites in eastern Russia for over 100 years and have developed some resistance through natural selection.

In Russia, the colonies harboured lower levels of Varroa mites than U.S. colonies:

• untreated colonies in the U.S. had infestation rates of 33% and were collapsing from Parasitic Mite Syndrome?, whilst
• untreated colonies of Russian bees in Russia only had infestation rates of 7% over the same time period.

In the USA, after three months without treatments,

• domestic colonies had a 17,300 increase in Varroa mite levels, whilst
• Russian colonies had only a 250% increase.

They have a high degree of VSH behaviour, and they also cease brood production completely in times of food shortage (such as a dearth in the summer). This cease in brood production reduces the availability of brood cells for mites to reproduce inside, so their population decreases.

Additionally, in the USA, Russian honey bees:

• Produce quantities of honey ≥ domestic bees, and
• Demonstrate resistance to tracheal mites.

#################### Saskatraz

Saskatraz

The Saskatraz breeding program started in Saskatchewan, Canada, in 2004. The goal was to develop a stock of bees that produced a lot of honey, overwintered well in cold climates, had a gentle temperament, resisted brood diseases and viruses, and exhibited hygienic behaviour.

Colonies in this breeding program are tested every year for these traits and breeder queens are selected from the top performers. The program began commercial queen production in 2012. Saskatraz stock is available as either queen cells or pure Saskatraz queens from Saskatchewan, Canada, or as Saskatraz hybrids from Olivarez Honey Bees, Inc., in Northern California.

#################### Varroa Sensitive Hygienic (VSH)

Varroa Sensitive Hygienic

This stock was developed by Dr. John Harbo and Dr. Jeffrey Harris at the USDA's Bee Breeding Lab in Baton Rouge, Louisiana. Varroa Sensitive Hygienic bees kill and remove pupæ from cells that contain reproductive mites. Immature mites die because they desiccate (dry out) quickly once the cells are opened. In this way, mite reproduction is interrupted and the growth of the mite population is slowed.

If there are many bees in a colony that perform hygienic behaviour, this can significantly lower the mite population. The impairment of mite reproduction is why this queen line was named Varroa Sensitive Hygienic (VSH). Additionally, when non-VSH queens were introduced to colonies previously headed by VSH queens, the mite population increased.

When VSH queens have been introduced to commercial colonies in the U.S., they have helped significantly reduce mite levels. One study found that colonies headed by pure VSH queens reduced mite infestation levels by 76% and daughter VSH queens (that mate openly with random drones) reduced mite infestations by 44%, compared to colonies headed by non-VSH queens, which reduced mite infestations by only 7%. Another study comparing VSH colonies and Italian colonies in U.S. commercial apiaries found VSH colonies required fewer mite treatments during the study period: Only 12% of VSH colonies required mite treatments, while 40% of Italian colonies required mite treatments. Furthermore, both stocks produced similar amounts of honey.

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