Avocado Pollination by Honeybees

This is the season for avocado pollination in our little town of Fallbrook, known as the avocado capitol of the world. Avocado trees come from Mexico where a native stingless bee provides the pollination. Since that pollinator doesn't live here, honeybees have taken over the job. Every fruit produced depends on pollen being transferred from one flower to another, so honeybees become the most valuable citizens in town during the few weeks when the trees are in bloom.

Avocados have an odd system of pollination to insure cross pollinization. Each of the inconspicuous green/yellow flowers has both male and female parts, but only one sex is open at a time to prevent self fertilization. There are two kinds of trees, A and B types. The A type trees have their flowers open in the mornings as females. The flowers close by afternoon, and remain closed until the following afternoon, when they reopen with the male parts now producing pollen. The B type trees open their flowers as female in the first afternoon, they close and reopen as males the following morning. Each flower only opens twice. If a grove is properly planted with both types of trees, and if pollinators are present then a good set of fruit is likely. Honeybees do the vast majority of the pollination here, but wild bees, flies, wasps and even hummingbirds are also seen working the flowers.


Fallbrook was founded by the Reche family in the late 1800's, and they just happened to have been beekeepers. Back then the landscape was dominated by the native chaparral plants which are superb honey producers. At one time San Diego County was the number one honey producing county in America. Today, with only about 10% of the chaparral left, this is no longer the case. Urbanization has forced those beekeepers that are left to flock to areas like Fallbrook where bees are still welcome. So a symbiotic relationship has formed between growers and beekeepers; we both need each other.

Read more about avocados and bees here or Wikepedia

Bee hunting

We recently went out to one of our favorite camping spots, Coyote Canyon in the Anza-Borrego desert. This is a unique spot because it is one of the few places in this vast desert that has a year round water source, Coyote Creek, which is actually the longest creek in San Diego county.

Because of the reliable source of water and the abundant spring wildflowers, it also supports a good number of feral honeybee colonies, now mostly Africanized. Finding a wild colony in this sort of landscape though is a bit like finding a needle in a haystack. But using some knowledge of bee behavior, a little logic and a keen eye and ear, it's possible to let the bees tell you exactly where their hive is located.

Here is a picture of a feral colony we first located back in 1997. We return every winter to check on it, and it has been occupied every year. In the summer the hot sun shines into the rock crevice and melts a good part of the hive away, the floor is covered with melted wax. We'll return in a couple months to see the desert carpeted in wildflowers. At that time we'll put up a little thatched sun shade to help them through the summer heat.

Many years ago I spent a week on Santa Cruz Island off the central California coast, learning how to hunt wild honeybees from a real expert. Dr. Adrian Wenner, Professor Emeritus at the University of California at Santa Barbara, was working with the Nature Conservancy to bring the island back to a more natural state by trying to eliminate non-native species. One real problem were the European honeybees pollinating imported European plants such as fennel, which was taking over the island. In the 1870's a few hives were taken to the island where they prospered, swarmed, and soon filled every niche on the island. Dr. Wenner's plan was to locate all the colonies so that he and his team of graduate students could systematically eliminate them. As a bee breeder I was interested in obtaining some of these survivors as breeding stock before they were eliminated, that's how I ended up spending a fascinating week learning the long lost art of bee hunting.

Dr. Wenner is perhaps best known for his challenge to the validity of Karl von Frisch's theory of honeybee dance language, for which von Frisch was awarded a Nobel Prize in 1973. Dr. Wenner's contention that odor cues alone were enough to explain the remarkable nectar finding skills of honeybee colonies sparked a heated controversy which continues to this day nearly four decades later. Dr. Wenner used his own theory to develop a technique of bee hunting to locate more than 160 colonies on Santa Cruz Island over the years. But as hard as they tried to eliminate the colonies, they never could keep ahead of the reproducing colonies. In the end they decided to introduce Varroa mites which wiped out the island bees in a few years. Although the last time I talked to Adrian he thought there was perhaps one colony still hanging on. As a beekeeper I'm rooting for their comeback,this time as mite resistant bees. The island has now become a part of the Channel Islands National Park.

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Explore the island by zooming in with the plus button on the map controls, or just double click where you'd like to see. Zoom way out with the minus button to see our favorite camping spot in Coyote Canyon.