While people across the nation express their love this week with poems, kisses, and chocolate, another kind of powerful attraction is taking place in California’s almond orchards: pollination. Mid-February through March is the time of the almond tree’s yearly mating ritual. Its abundant flowers emerge, seductive petals opening to reveal male and female reproductive parts, sending out a scented invitation to bees.
Every ripe cherry, corn kernel, almond, pea and plum you eat is the direct product of a fertilized egg. In plants, reproduction begins with pollination, the process by which pollen (which contains a sperm cell) is transferred from an anther to a stigma. Sperm then travel down a tube to an egg-bearing ovary and, once a sperm has planted itself into the egg, a tiny embryo is formed within a protective seed. The ovary tissue swells to form the pericarp, which we call fruit. Many of our favorite foods—grains, nuts, and fruits—are almost entirely dependent upon this amazing course. While some plants have flowers that contain both female and male reproductive parts and are self-fertile, many require pollen from a different plant of the same species to reproduce. In these cases, a vehicle must transport the pollen. Insects, birds, bats, wind, water and even humans can act as these vehicles; they are pollinators. Today’s article explores pollination by honeybees.
The shapes, colors, and scents of many flowers are a result of years of coevolution of plant and bee. Bees visit flowers primarily for the nectar that will, after much of the moisture is evaporated, become the honey that feeds growing bees (and people). During these foraging trips, bees inadvertently become agents of the plants’ survival by causing pollination. Bees are attracted to particular flower colors and scents that indicate nectar flow. While bees are collecting the nectar, pollen sticks to their fuzzy bodies and serendipitously rubs off onto the stigma of the next flower they visit. During some foraging flights, bees also collect and deposit pollen in small pollen baskets on their legs; during these times they are far more effective as pollinators.
In agriculture, pollination is a big business. Among the crops that depend on pollination from honeybees (although some not exclusively) are blueberries, summer and winter squash, melons, cucumbers, peaches, almonds, cherries, plums, apples, and pears. Much like seasonal farm workers, honeybees often come from afar to perform their important role in the agricultural system. Beehives are shipped across the United States in semis and from other countries on cargo boats. In fact, over half of the commercial hives in the United States are in California’s Great Central Valley right now. The almond bloom happens from mid-February to March, and during the bloom, almond growers need two beehives (each of which contains around 20,000 bees) per acre for their almonds to be sufficiently pollinated and produce the seeds that are their crop. Since California produces 80% of the world’s almonds, honeybee demand in our state skyrockets during this period. The going rate to rent a hive for the brief almond bloom is about $150. This adds a significant cost to production, even for small orchards.
It isn’t so expensive for all growers to get their crops pollinated. Stan Devoto, who grows over 50 varieties of apple, pays just $25 per hive. The reason for the price difference is that apple blossom honey is harvestable. Bees that consume almond nectar create only a small amount of bitter honey, so the honey is not part of the beekeeper’s compensation.
Before the advent of industrial agriculture after World War II, farms relied upon some of the over 4,000 species of native wild bees for a good deal of pollination. But wild populations are not as manageable as the domesticated honeybees; they often nest in the ground or in trees and cannot be shipped—nor do they provide the abundant honey harvest humans value so highly. Wild bee populations have been declining from pesticide poisoning, habitat destruction, and competition from honeybees; meanwhile, commercial bee populations have also dropped dramatically. The number of commercial beehives in the US is less than half of what it was in 1940. The primary reason for this shrinkage is outbreaks of mites that attack bees at all stages of life. Because of the mites, demand for pollinators from Central Valley almond growers was not met last year. Many wild bees show resistance to mites and they have been suggested as an alternative to the honeybee problem. But these native species won’t survive in the industrial, monocultural, pesticide-intensive agriculture that predominates in the United States. With luck, sustainable practices and the much-needed support of research dollars, perhaps growers may again be able to rely on wild bee pollination. For now, though, most fruit and nut growers at the Ferry Plaza Farmers market are making do with the honeybees that are available, some through partnerships with the beekeepers that sell their honey at the market.
This year, almond grower John Lagier has a contract with Marshall’s Farm to rent 72 hives to pollinate his 36 acres of almonds. The Marshalls rent hives to just three almond growers -- honey sales make up the bulk of their business. But hive rentals are a good supplement during winter months. This arrangement works nicely for Lagier, too, since it is sometimes difficult for small growers to get a contract for so few hives. Jim Talboy of Tunitas Creek Apiary keeps 17 hives on Tierra Vegetables farm and harvests the honey a few times each year; farmers Lee and Wayne James enjoy the benefit of cucumber, pumpkin, squash and melon pollination. Some farmers also keep their own bees, selling the honey for extra income. Others do their best to attract pollinators by creating habitat, and not spraying harmful pesticides.
*To read the CUESA newsletter published on 6/29/07 regarding Colony Collapse Disorder in bees, go here.