We read and learn much about bees and other pollinators and their decline. Pollinators have their mission from Mother Nature to pollinate between 75 and 90% of all the plants on Earth, and about one third of our food comes from plants pollinated by animals. But the pollinators are in decline worldwide. The two most significant causes are loss of habitat and pesticide use.
Just who are the pollinators? The majority of the pollinators are bees, but the list also includes wasps, flies, butterflies, moths, beetles, bats, and birds (mostly hummingbirds in North America) and even a few ants.
When we think of bees, we most often think of the honey bee which was imported from Europe. But there are around 4,000 native bees in North America. California has about 1600 species of native bees. These bees are also in decline like the honey bee and need every bit of our help.
The native bees are typically much more efficient and faster pollinators than the honey bees. For example, a study was done that determined that only 250 female blue orchard bees were needed to pollinate an acre of apples that would have required two hives of honey bees, with 15,000 to 20,000 honey bees each.
The native bees don’t need to be kept by us but they need good nesting sites, a good supply of flowers throughout the growing season, and no pesticides.
Most of the native bees are solitary. They usually live for one year. The female spends her whole adult life building a nest and storing provisions for her young. Many nests are in the ground. Some are tunneled into dead wood. Once the nest is ready for provisioning she forages the flowers and gathers nectar and pollen which she mixes and forms into a loaf and stores into each cell prepared for each egg she lays. Then she dies and her young will emerge the following spring.
Nesting sites for wild bees include dead logs and twigs. So leaving a few piles of fallen twigs around, and a dead log or two will provide some bee habitat. Leave them out well before spring so that new emerging bees will find them for their new nests. Crevices in rocks and rock walls provide habitat, as does compacted bare dirt, so be sure not to mulch everything! Leave some dirt pathways or open space free of mulch. Some bees nest in the spent stems of flowers. At the end of the season flower stems of Rudbeckia, Echinacea, sunflowers, and others can be left standing, offering nesting sites for bees and seeds for birds. Wait until spring to cut them back, and cut at the bottom and keep them in a loose pile for a while to assure the new bees have safely emerged.
Keeping a garden with a wide range of flowers on trees, shrubs, and perennial and annual flowers will help to supply the nectar and pollen the wild bees need. Since the native bees evolved with native plants, these are the most ideal plants to select. A few of my favorite shrubs are Toyon, Coffeeberry, Manzanitas, Red Flowering Currant, and the Cleveland Sages. Many flowers will work and there are many lists of suitable plants you can find online. The goal is to have flowers throughout the season for a steady supply of pollen and nectar.
Try to team up with others in your neighborhood to provide forage flowers for the bees. It has been shown that the bee populations are larger and more diverse in areas that have many small gardens nearby rather than isolated gardens. But everything helps!
Bees need to live in an environment free of pesticides. The neonicotinoids have been very strongly suspected of doing damage to bee populations. Use plants that are free of this insecticide. The chemical imidicloprid is a neonicotinoid that is often used as a systemic insecticide. Once inside the plant it can affect bees for a long time.
We live in an ecologically rich area and it may be hard to think of habitat loss as something we should worry about here. But if you look at the big picture, in the United States, landscape ecologists have deduced that we have changed, paved over, built upon, and replanted with exotic ornamentals and crop plants a good 95% of our land in the lower 48 states. That leaves only 5% of native lands and those are fragmented and scattered. So we can and should look at our own landscapes and gardens as a place to truly help support and increase the bee and other pollinator populations.
This is not the best time of year to observe the variety of native bees living here, but come early spring when the manzanita opens its flowers, do take some time to see an amazing variety of bees. Throughout the warm flowering season you may observe mason bees, bumble bees, carpenter bees, sweat bees, the ultra-green sweat bees, the tiny little blue ‘Jewel bee’, and many other bees that have only scientific names. Some of these flying insects may not even be bees but, instead, are flies that look like bees in order to scare away predators.
I have just barely begun to try to learn the different bees, and I look forward to next spring, armed with my new bee guide, The Bees in Your Backyard by Joseph S. Wilson and Olivia Messinger Carril, to learn much more. This book gives lots of information on creating habitat and even houses and nests to build for some of the bees, in addition to identifying all the bees. There is another new book out called California Bees and Blooms: A Guide for Gardeners and Naturalists by Frankie, Thorp, Coville, and Ertter. There is a lot of information online from great sources such as the Xerces Society, university entomology departments, the Fish and Wildlife Service, and so on. Type in wild bee pollinators to get you started.
This article also appeared in The Union, Feb. 24, 2018.