Breeding Hilo Bees

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.

Queens

Three kinds of queens are used in the Hilo Breeding program.

Single-drone inseminated (SDI) queens create colonies of highly related workers. SDI colonies are powerful units for testing Varroa resistance because these colonies have a high probability of having the genetics that regulate VSH. Reducing the ‘noise’ of multiple drones helps resolve the mite resistance to select that trait with confidence, and to guide decisions to keep or cull these lines.

Multi-drone inseminated (MDI) queens typically combine genetics from selected SDI colonies into colonies that are used as breeder colonies or are potential breeder colonies (i.e., that are still undergoing testing). MDI-queen colonies can be assessed for mite resistance and other traits.

F1 queens are naturally mated daughters of SDI or MDI queens, and are used for two purposes. A group of F1 queens grafted from one mother may be used in progeny tests to determine whether to select the parent queen as a breeder. F1 queens are also used as drone-source colonies in isolated mating areas where drone-source colonies with high VSH are needed to make production queens.

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. Varroa resistance is measured in two ways.

The best evaluation of a colony’s mite resistance comes from measuring the proportion of non-reproductive Varroa in late-stage pupae. In the Hilo program, each SDI colony is inoculated with 200 Varroa collected from mite rearing colonies. Twelve days later, 300-400 brood cells with purple-eyed pupae are opened and examined at 5X magnification with a stereomicroscope. In cells that have an adult female mite, the reproductive status of mites is determined by the presence, age and sex of progeny. The infestation rate and number of non-reproducing mites are both used to select for mite resistance.

Mite resistance is also evaluated by measuring mite infestation on adult bees in colonies with MDI queens and F1 field colonies over time. A standard mite-wash technique is used to measure the number of mites per 100 bees.

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.