Queen Rearing: Grafting and the Breeding Industry

The difference between a worker bee and a queen is not genetic. It's nutritional. Every fertilized egg in a honey bee colony has the potential to become either one. The determination happens in the first three days of larval life, based entirely on what the larva eats. Worker larvae receive royal jelly for three days, then switch to a mixture of honey and pollen. Queen larvae receive royal jelly for their entire development. The jelly - specifically a protein called royalactin, identified by Masaki Kamakura at Toyama Prefectural University in 2011 - activates an epigenetic cascade that produces a larger body, functional ovaries, a spermatheca for storing sperm, and a lifespan of 3 to 5 years instead of 6 weeks.

Same genome. Different menu. Different animal.

This biological fact - that any young larva can become a queen if fed correctly - is the foundation of the entire queen rearing industry. If queens could only come from special eggs, laid in special cells, under special conditions, commercial queen production would be impossible. Instead, the queen rearing process starts with a beekeeper picking up a larva with a tool and moving it to a different cup. The bees do the rest.

The Graft

Grafting is the transfer of a young worker larva from its cell into an artificial queen cup - a plastic or beeswax cup roughly 9 millimeters in diameter that mimics the proportions of a natural queen cell. The tool used is called a grafting needle - a thin, slightly hooked instrument that slides under the larva and lifts it, along with a film of royal jelly, from the bottom of the cell.

The larva must be less than 24 hours old from hatching. Ideally, 12 to 18 hours. At this age, the larva is approximately 1 millimeter long - a translucent crescent floating in a pool of milky jelly. Under natural conditions, nurse bees would have already been feeding it royal jelly since it hatched. If the graft succeeds, they'll continue feeding it royal jelly in the new queen cup. If the larva is too old - more than about 36 hours - the critical window for full queen development has partially closed, and the resulting queen may be smaller, less fecund, and shorter-lived.

The grafting process requires good eyesight (or magnification), a steady hand, and practice. Commercial queen rearers graft hundreds of larvae in a session. The cups are mounted in bars, the bars are mounted in frames, and the frames go into "cell builder" colonies - strong, queenless colonies packed with nurse bees and resources. The nurse bees discover the larvae in the queen cups, recognize them as potential queens (the cups' size and orientation trigger the response), and begin provisioning them with royal jelly.

Within 24 hours, the cell builders have drawn out the cups into elongated peanut-shaped queen cells. Within 5 days, the cells are capped. On day 16 from the original egg (or roughly day 13 from grafting, depending on larval age at transfer), the queen emerges.

The Cell Builder

The cell builder colony is the biological factory floor. Its job is to accept the grafted larvae and provision them lavishly - and provisioning lavishly requires specific conditions.

The colony must be queenless, or functionally queenless (some systems use a queen excluder to separate the cell-building area from the queen). Queenlessness triggers an emergency response: nurse bees begin producing royal jelly at maximum capacity, desperate to raise a replacement queen. This desperation is what the queen rearer exploits. A queenless colony with 20,000 nurse bees and plenty of incoming pollen and nectar will accept and provision grafted cells enthusiastically.

The "starter-finisher" method separates the process into two stages. A hopelessly queenless starter colony receives the grafted cells for 24 hours. The starter's urgency ensures acceptance and initial provisioning. Then the cells are moved to a "finisher" colony - a queenright colony with a queen below an excluder - where conditions are calmer and more stable. The finisher colony provisions the cells at a steady rate for the remaining development period.

The alternative is the "cell punch" method, which skips grafting entirely. Instead of moving larvae, the queen rearer finds cells containing larvae of the right age in a donor colony, cuts them out of the comb, and places them directly into cell cups or cell protectors. This is simpler but less precise - you're limited to whatever larvae you can find at the right age, rather than selecting from a chosen queen's offspring.

The Numbers

The United States produces roughly 1 million queens per year. The number fluctuates - colony losses in bad years drive demand higher - but the scale of the operation is industrial.

Hawaii is the epicenter. The islands' year-round warm climate allows queen production during months when mainland operations are shut down. Major Hawaiian queen producers ship queens to the continental US beginning in January and February, when mainland beekeepers need to replace winter losses and build up colonies for the almond pollination season in California. A single Hawaiian operation can produce 100,000 queens per year.

California, Georgia, Texas, and Louisiana are the other major production states. The queens ship via USPS Priority Mail in small wooden or plastic cages, each containing the queen and a handful of attendant workers, with a candy plug at one end. The candy - a mixture of fondant and powdered sugar - takes the receiving colony's workers 2 to 3 days to eat through, by which time they've acclimated to the new queen's pheromone profile and are less likely to kill her.

Queen prices range from $25 for an unmarked Italian queen to $1,000 or more for an instrumentally inseminated breeder queen from proven genetic stock. The median price for a standard production queen is $30 to $45. Commercial beekeepers managing thousands of colonies might buy 500 to 1,000 queens per year. The logistics of queen distribution - shipping live insects through the postal system with a 48-hour viability window - is its own minor miracle.

The Mating Flight

Under natural conditions, a virgin queen mates during one or two mating flights taken 5 to 14 days after emergence. She flies to a drone congregation area - a consistent location in midair, typically 10 to 40 meters above ground, where drones from colonies across a wide area gather and wait. The congregation areas are remarkably stable. The same airspace serves as a mating zone year after year, even after all the drones from a given year have died. The location is maintained by some combination of landscape features, wind patterns, and magnetic cues that the drones detect independently.

The queen mates with 12 to 20 drones during her flights - each mating lasting seconds, each drone dying immediately after. She stores the semen in her spermatheca, a specialized organ that keeps the sperm viable for years. She never mates again. Every fertilized egg she lays for the rest of her life uses sperm from those mating flights.

For commercial queen producers, this open-mating system creates a problem: no control over the drones. The queen flies out. She mates with whatever drones are in the area. Those drones could be from feral colonies, from a neighbor's apiary, from Africanized stock in southern states, from any genetic background. The queen producer controls the maternal genetics but not the paternal side.

Isolated mating yards - apiaries placed in remote locations where the only drones within flight range are from the producer's own stock - partially address this. But a queen can fly 5 to 10 miles to mate, and drones can fly similar distances. True isolation requires geography: islands, mountain valleys, or the middle of agricultural desert where no feral colonies survive.

This is why Hawaii works so well for queen production. The islands are surrounded by ocean. Drone flight ranges don't cross 2,400 miles of Pacific. If you control every colony within 10 miles, you control the genetics.

The Syringe

Instrumental insemination (II) - the manual collection of drone semen and its injection into an anesthetized queen - eliminates the mating flight entirely. The queen's genetics are controlled. The drone genetics are controlled. The resulting offspring have a known pedigree on both sides.

The technique was first developed by Lloyd Watson in the 1920s and refined through the mid-20th century by Harry Laidlaw at UC Davis, who is widely considered the father of modern instrumental insemination. Laidlaw's equipment design - a binocular microscope, a queen holder, a micro-syringe with a glass tip, and a CO2 anesthesia system - is essentially the same system used today.

The process: drones are collected from colonies with desired traits. Each drone is squeezed gently until he partially everts his endophallus. The semen - a tiny volume, roughly 1 microliter per drone - is collected into a glass capillary syringe. Semen from 8 to 12 drones is pooled. The queen is anesthetized with CO2 (which also triggers her to begin laying), held in a positioning device that exposes her reproductive tract, and inseminated by injecting the pooled semen through her vaginal orifice into the oviducts using the microsyringe.

The entire procedure takes about 10 minutes per queen. The success rate - defined as the queen successfully beginning to lay fertilized eggs - is 80 to 90 percent in experienced hands. The equipment costs several thousand dollars. The skill requires training and practice. Very few beekeepers perform II on their own queens. Most purchase instrumentally inseminated breeder queens from specialized producers and use those queens as the mothers for their grafting program.

The implication: a commercial queen producer buys one II breeder queen for $500 to $1,000. She grafts from that queen's larvae. The grafted queens mate openly but carry the breeder's maternal genetics. The next generation of queens from those colonies carries the selected traits forward. The II queen is the genetic anchor of the operation - the one animal whose pedigree is fully controlled.

The Breeding Programs

The major honey bee breeding programs in the US are built on instrumental insemination and controlled mating. The USDA Baton Rouge Bee Lab maintains selected lines. The Purdue "ankle-biter" program breeds for Varroa-sensitive hygiene. The Minnesota Hygienic line, developed by Marla Spivak, selects for bees that detect and remove diseased brood. The Russian bee program, run through the USDA lab since 1997, imports and evaluates Primorsky territory genetics that coevolved with Varroa.

Each program follows the same basic pipeline: identify a trait (disease resistance, mite resistance, gentleness, honey production), select colonies that express it, graft from those colonies' queens, control the mating as tightly as possible, evaluate the offspring, and repeat. The generational cycle is fast - a new queen generation can be produced every 4 to 6 months - but the selection intensity is limited by the fact that each queen mates with multiple drones. The genetic diversity introduced by polyandry is an advantage for colony health (multiple patrilines increase disease resistance) but a disadvantage for breeding precision (the trait you selected for gets diluted by unknown drone genetics).

This is why breeder queens are expensive and production queens are cheap. The breeder queen's value is in her known genetics. The production queen's value is in her ability to lay eggs and produce a functional colony. The genetic precision degrades with each generation unless the pipeline is maintained.

The Hawaiian Pipeline

The Hawaiian queen production industry exists because of timing, geography, and almonds.

Almond pollination in California begins in February. Commercial beekeepers need colonies at full strength by late January. Colonies that lost their queens over winter need replacements. Colonies that are too weak need queens for splits. The demand spike for queens occurs in January through March - months when mainland queen producers can't produce queens because there are no drones flying and the weather doesn't support mating flights.

Hawaii has no winter. Drones fly year-round. Mating flights happen in December and January. Queens produced in January can be in California by early February. The Hawaiian queen industry - concentrated on the Big Island and Maui - supplies the mainland's early-season demand that no continental producer can meet.

The pipeline is remarkable: larvae grafted in a Hawaiian apiary in December become mated queens by early January, get caged, shipped via overnight air freight to the mainland, and are installed in California colonies by mid-January, in time for those colonies to build up for almond bloom in mid-February. The entire process from graft to field deployment takes about 5 to 6 weeks.

The risk in this pipeline is disease transmission. Hawaii has small hive beetle. It has Varroa. Queens shipped from Hawaii come in small cages with a few attendant workers, and those workers can carry mites. The attendant workers are the vector. Some beekeepers remove and destroy the attendants before introducing the queen to minimize transfer risk.

The 72-Hour Window

The entire queen rearing industry rests on a biological constraint: the larva must be young enough when it begins receiving exclusive royal jelly for the epigenetic program to execute completely. A larva grafted at 12 hours old produces a queen with full-sized ovaries, a large spermatheca, and a well-developed mandibular gland system. A larva grafted at 36 hours produces a queen that's physically smaller, with fewer ovarioles and less pheromone output. A larva grafted at 72 hours produces something between a queen and a worker - an "intercast" that lays poorly and is rejected by the colony.

This window is the quality control bottleneck. Miss the age, and no amount of feeding or care produces a good queen. Get the age right, and the nurse bees do the rest - they'll produce a queen of the maximum quality their nutrition and genetics allow.

Commercial producers manage the window by caging the breeder queen on a frame of empty comb for 24 hours. When the cage is removed, every egg on that frame is the same age. Three days later, every larva is the same age. The grafter knows exactly what she's picking up. The precision of the timing determines the precision of the product.

This is why queen quality varies. A $30 queen from a high-volume producer may have been grafted from a larva of uncertain age, raised in a cell builder that was overloaded with too many cells, and mated in an area with uncontrolled drone genetics. A $200 queen from a specialty breeder was grafted from a larva of known age from a selected mother, raised in a well-provisioned cell builder with limited cells per frame, and mated in an isolated yard or instrumentally inseminated. The product looks the same - a mated queen in a cage - but the developmental history determines the performance.

Manufacturing Life

Queen rearing is the only branch of animal husbandry where the product is a single female insect shipped through the postal system in a box smaller than a deck of cards, where the manufacturing window is measured in hours, and where the quality of the product determines the survival or failure of a colony of 60,000 animals.

It's also the branch of beekeeping that most clearly illustrates the tension between natural process and industrial demand. A colony left to its own devices will raise a queen when it needs one - when the old queen dies, when she fails, when the colony swarms. The colony will raise multiple queen cells, the first queen to emerge will kill the others, and the survivor will mate and begin laying. The process takes about a month and requires no human involvement.

The industry can't wait a month. The industry needs queens in January. It needs them genetically consistent. It needs them by the thousand. So the process has been disassembled into its component biological steps - larval transfer, cell building, mating control - and each step has been optimized for throughput, timing, and quality.

The biology doesn't mind. The larvae don't care that they were moved from one cup to another by a human hand. The nurse bees provision grafted cells with the same dedication they'd give to a natural queen cell. The queen that emerges doesn't know she was manufactured.

She mates, or she's inseminated. She begins laying. She produces pheromones that hold the colony together. She is, in every functional sense, a queen. The only difference between her and a queen raised naturally is that someone chose her mother, chose her birthday, and put her in a box with a stamp on it.

One million queens. One million postal deliveries. One million colonies that depend on a larva that was one millimeter long and 12 hours old when someone slid a needle under it and moved it one centimeter to the left.