The Breeding Process


Since 2015, Hilo breeding has focused on refining lines of bees that previously were identified as having mite resistance, but were not consistently productive. The process produced a pool of highly Varroa resistant bees, which in 2020 are being collected into a semi-closed population for long-term maintenance.

Genetics

The Hilo program has incorporated genetics from a variety of commercially-based sources.

Early importations of VSH semen from the USDA lab formed the basis of stock in Hawaii (during 2009-2014; see History). Ongoing imports of Pol-line semen were imported from the USDA lab and refined. Later, genetics from various commercial bees in Hawaii were tested and added when appropriate. Genetics are controlled in the Hilo population by using instrumental insemination to cross selected queens and drones. Records of mite resistance and performance of these offspring are maintained and used to make breeding decisions, some dating back to 2006.

The Breeding Process

Since 2020, the Hilo Bee population has been maintained as a semi-closed population composed of two subpopulations. One subpopulation has legacy Hilo genetics (including original VSH/Pol-line genetics from 2010-2016, and the other is a mix of Hilo and current Pol-line genetics. Both subpopulations are evaluated and propagated each year. Colonies are evaluated for mite resistance, honey production, population size and temperament. In each subpopulation, 10-20 breeder colonies are selected from a starting group of about 200 potential breeder colonies. Queens are reared from each breeder colony, and queens are instrumentally inseminated with a mix of semen from the subgroup’s breeder colonies.
 
Two complementary efforts are aimed at improving honey production in Hilo Bees by adding genetics from outstanding field colonies. “Low-mite colonies” are sought out by sampling Varroa infestations in the 6800 production colonies managed by Hawaii Island Honey Company; this commercial population of Hilo-based bees receives infrequent mite treatments. Exceptional low-mite colonies are then monitored for an additional six months to verify productivity and other characteristics. On the mainland, queens from the most productive colonies in field tests of Hilo Bees in commercial beekeeping operations are being retrieved, and semen from drones of their daughters is being sent back to the Hilo program.
 
Inbreeding in Hilo Bees is minimized in several ways. The subpopulation structure allows mating areas to provide drones from one subpopulation to mate with queens grafted from the other subpopulation. Inbreeding also is slowed by selecting a large number of breeder colonies from a large pool of potential breeder colonies, and by occasionally adding genetics from outside the current Hilo Bee population. No signs of inbreeding have been observed in Hilo Bees, and research found good genetic variability in the population at a critical site in the genome (http://dx.doi.org/10.1007/s13592-020-00790-1).
Many queens of different types are created and tested in the program each year:

Testing for Varroa Resistance

Breeding Hilo Bees relies on consistently high Varroa resistance in both queens and drones. Resistance is measured in two ways.

The best evaluation of a colony’s mite resistance comes from measuring the expression of Varroa sensitive hygiene, i.e., the proportion of non-reproductive mites in worker brood.  This method was used extensively for the first five years of the Hilo program to increase mite resistance. An explanation of the testing method can be found here: Harbobeeco.com/measure-vsh/
 
Since high mite resistance is established in the Hilo population, infestations are now mostly evaluated by measuring mite infestation on adult bees in potential breeder colonies and field colonies over time. A standard, beekeeper-friendly mite-wash technique is used. This allows many observations to be made under field conditions.
Varroa resistance is measured in many colonies each year:

Field Observations

All colonies in the breeding program are evaluated every 3-6 weeks.

Evaluations assess queen survival, colony population, brood quality, temperament and honey yield. Colonies with unacceptable characteristics are culled from the program, and usually re-queened.

Record Keeping

Records about the bees in the Hilo breeding program are maintained in a system called Queenbase.

The Queenbase software was developed by the Arista Bee Research Foundation to manage the extensive information generated over many years and multiple steps involved in testing and breeding honey bees. Information includes the history, performance and management of colonies, pedigrees of queens, general field activities and planning of breeding tasks.

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