Prepare to pollinate

Success in spring depends on skilfully managing beehives during the rest of the year. By Anna Mouton.

It’s easy to forget about bees outside the brief period when self-incompatible fruit trees are flowering. But the delivery of hives is preceded by months of colony manipulation designed to optimise pollinator performance.

Effective pollination requires colonies with the correct population structure and resources. Worker bees forage mainly to feed themselves and growing larvae. Excess food is stored in the hive. The queen bee lays eggs as long as food is plentiful and space is available.

The ideal pollination hive has a horde of hungry larvae — workers feed each of their demanding younger siblings around 2 500 times daily. Larvae use nectar for energy and pollen for protein, so lots of larvae translate into plenty of pollination.

Larvae represent the next generation, as pollination hives need a pipeline of developing bees to replace worn-out workers. Worker bees live less than six weeks, and foraging workers are nearly entirely renewed during their stint in an orchard.

Workers gather food, feed larvae, and maintain and air-condition the hive. Hives function best with about two frames of workers for each frame of developing bees — more on frames later.

A thriving colony eventually runs out of space, and the queen stops laying. She and a subset of her workers may even leave the hive to start a new colony elsewhere. The old colony will generate a young queen to succeed her.

What do beekeepers do?

Most beekeepers use Langstroth hives with 10–11 removable frames suspended vertically in the brood box. Some hives have a smaller second box of frames called a super on top of the brood box.

The bees build combs of cells into the frames. The queen lays eggs — up to 2 000 every day — in some cells and the workers store honey and pollen in others. Excluding the queen from the super restricts it to storage space.

Beekeepers strive for a pollination hive containing at least four frames of brood — eggs, larvae, and pupae inside cells — and enough workers to cover the surface of at least eight frames. No more than five of the remaining 6–7 brood-box frames should hold stored food. Hives with a super should not have more than two frames of honey in the super.

This population structure ensures enough hungry larvae to keep workers scrambling for food and enough developing bees to keep the pollination labour force strong. Limiting stored food motivates workers to get out into the orchard.

Space and food are the levers beekeepers pull to manipulate the population structure. They replace full frames with empty ones so the queen always has space to lay eggs. Surplus frames of brood or food can be used to augment weaker hives or start new colonies.

The speed at which queens lay compels beekeepers to monitor hives and adjust frames every 2–3 weeks in the 2–3 months leading up to pollination season.

A steady food supply stimulates the queen to lay eggs. Beekeepers control food by relocating their hives and feeding their bees — they’re not only moving hives for crop pollination.

From season to season

Crop pollination takes a heavy toll on bee colonies because bees are introduced at high densities to maximise fruit set, and orchards generally don’t have enough forage. Unattractive flowers and netted orchards exacerbate colony decline. Beekeepers usually have special sites where they take their hives for rest and recovery after the pollination season.

Hives can remain in these safe spaces for the rest of summer and up to canola-flowering time in winter. The queen reduces laying as the colony shifts from a reproductive to a honey-production phase. The workers collect less pollen but must still have access to ample nectar.

The next round of frenetic beekeeper activity ramps up as soon as canola starts flowering. It’s the go-to forage for rebuilding colonies before the Western Cape pollination season — the hectares of concentrated pollen- and nectar-rich canola flowers boost egg-laying by the queen.

Canola only flowers for 8–10 weeks, so beekeepers must rush to move their hives. Sometimes, the canola isn’t flowering enough when hives arrive, and beekeepers feed their bees until bloom takes off.

The first week in canola is when beekeepers check all their hives for diseases and adjust the frames. Frames of food are taken out to make space for egg-laying. Frames of brood are redistributed from stronger to weaker hives — bees are happy to raise brood from other hives — stimulating the strong hives to fill more brood frames.

During canola flowering, beekeepers service their hives every 2–3 weeks. They’re continually tweaking each hive to achieve pollination readiness.

Finally, spring arrives, and pollination gets underway. Beekeepers do final hive manipulations to remove stored food and add empty frames. They load up their hives and deliver them to flowering crops all over the province. The vital first step in producing the season’s crop is now up to the bees.

Behind the scenes

Fruit growing has at least one significant advantage over beekeeping: fruit trees don’t have to be moved several times yearly. Finding suitable off-season locations for hives is a challenge — especially as many beekeepers don’t own or control land with bee-safe spaces.

Good sites for hives must offer forage. A moment’s reflection makes obvious the dearth of flowers during much of summer in the Western Cape. Our summer-growing crops finished blossoming in spring, but winter-growing crops and natural veld await winter rains.

Eucalyptus trees — demonised as alien and invasive — are effectively the only flower show in town in December and January and, therefore, indispensable to healthy hives. The aggressive removal of all eucalyptus species threatens honeybees and, thus, the production of most pome and stone fruit.

Honeybees are further under pressure from climate-change-related warming and recurrent droughts, floods, and fires. They also suffer the more direct man-made hazards of agrochemicals and vandalism.

The result is that beekeepers search harder for and drive farther to off-season sites. They also travel hundreds of kilometres while shuffling hives between these sites, canola, and other crops. And then they travel hundreds more to service the hives — a beekeeper typically makes ten trips from taking hives to canola to removing them from their final pollination.

Fruit growers are acutely aware of diesel and labour prices, so they will immediately recognise the financial implications of all this driving and time spent manipulating colonies. Add in outlays on artificial feed and equipment, and suddenly, pollination fees seem very reasonable.

Growers like to point out that fruit pays for everything, but for many cultivars, there is no fruit without honeybees and their keepers. And the time and money invested in hive management outside the orchard determines pollination success.