That’s a tarantula hawk feeding on a flower of my Edranol avocado tree. I watched it work that tree for five minutes, then fly to a Fuerte twenty feet away, and then come back to visit the Edranol flowers again. Ten minutes later, I found the tarantula hawk crawling on the flowers of my Pinkerton.

That’s a lot of potential pollination and cross pollination. From a tarantula hawk!

(What’s a tarantula hawk? Pepsis thisbe is its scientific name. It’s classified as a type of wasp, and the females are said to hunt tarantulas and paralyze them in order to lay their eggs inside. The females also are said to have very painful stings. I wouldn’t know.)

Most of us think of honey bees when we think of who pollinates avocado flowers. But there are myriad other bees, flies, wasps, beetles, and even butterflies that feed on the flowers of avocado trees and potentially pollinate them.

Over the past few months, I have been standing before my avocado trees with my camera and trying to capture the visitors to their flowers. Here are some of the characters I’ve caught:

Bees

Flies

Beetles

Butterflies

But who pollinates avocado flowers?

I saw many other critters on the avocado flowers in my yard this spring that I wasn’t able to capture. Are all of these visitors pollinating the avocado flowers though? Just because they land on a flower doesn’t mean they pollinate, right?

For pollination of an avocado flower, it’s necessary for pollen from a male flower to stick to the body of a creature that afterward visits a female flower where the pollen is deposited.

So a creature crawling on avocado flowers does not necessarily lead to pollination.

Ants crawl on avocado flowers but researchers don’t think they pollinate much. One reason is that pollen does not stick well to their relatively hairless bodies. In general, the more hair an insect has, the higher its potential to be a pollinator because pollen sticks to the hair.

(By the way, unfortunately, mere wind can’t pollinate avocado flowers. Some kind of insect is required to move the pollen between flowers. This has been demonstrated in many experiments. For example, Lesley and Bringhurst of UCLA wrote in the 1951 California Avocado Society Yearbook: “At Los Angeles no fruits set on trees of 15 varieties where large flying insects were excluded by cloth bags or screen cages . . .”)

Native pollinators

If we think for just a second, we say, “Of course honey bees aren’t the only pollinators of avocado flowers.” Avocado trees originate in the Americas whereas honey bees originate in Europe. Someone else must have been pollinating avocado flowers before honey bees met avocados.

Some researchers have studied the insects beyond honey bees that pollinate avocado flowers, and some are still learning more about this today:

• Gad Ish-Am and colleagues compiled a lot of research in “Pollinators of Avocado” that summarizes studies done around the world.

• There is an ongoing study, started in 2014 by Ben Faber and Gordon Frankie and colleagues, of native pollinators of avocado flowers in Ventura and Santa Barbara Counties.

My experience and observations in spring 2023

Last spring, 2023, was a worrisome time because the weather was often cool and rainy, and every time I would look at the flowers on my avocado trees I would see a few flies and native bees but almost never a honey bee. The trees were having a superbloom, but the honey bees, the most famous pollinators, were nowhere to be found. Will there be any pollination?

Come summer, however, I saw an abundance of fruit developing on most of my trees and I thought, “If it wasn’t the honey bees, then who was it?” Must have been the flies and native bees that pollinated.

In contrast, I visited some farms that also had lots of flowers but low fruitset in spring 2023. It was blamed on the cool weather. I suspect the blame should partly be placed on reliance on honey bees. Most avocado farms rent hives of honey bees during bloom time in order to accomplish pollination but do not cultivate habitat for native pollinators.

Want to increase avocado pollinators?

Grow flowers near your avocado trees so that pollinators have a reason to live there.

These don’t have to be flowers that you buy and irrigate. The bush sunflowers above I did buy some years back, but they are native plants that have happily reseeded and begun growing elsewhere in my yard, and I’ve never watered them. They grow like weeds, like the poppies shown above next to my Pinkerton avocado tree.

(More on plants for pollinators in my post, “Growing a Bee Garden in Southern California.”)

I also make homes for the native bees that nest in holes by drilling into blocks of wood. (See my post, “Native bee nesting blocks.”) It’s easy to do and it works. Look at the holes below that have been filled with native bee nests:

But far and away the most important way to increase pollinators for your avocados (and other food plants) is to provide food for them all year long in the form of flowers.

Then they provide food for you in the form of avocados!

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