Marin IJ Articles

Native bees and native plants

• Sara O’Keefe

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  Bumblebee collecting nectar and pollen on a Red-Flowered Buckwheat plant. Photo: Barbara Robinson

  “When California was wild, it was one sweet bee garden throughout its entire length, north and south and all the way across from the snowy Sierra to the ocean.” John Muir, “The Bee Pastures,” The Mountains of California (1894)

  Native bees produced those gardens; today, we have 1,600 species of native bees in California. They are diverse in appearance from each other and from honey bees, which were brought from Europe in 1622. Native bees can be less than an inch long and blue or green, while some others are large, black or yellow, and a full inch long.

  Apis mellifera, the honey bee, is social with queens and workers that live in hives with other bees, while 75% of native bees are solitary. Female native bees mate, make nests, lay eggs, and collect pollen for the young. Males mate and accidentally pollinate when collecting pollen for their own energy. Both are excellent pollinators.

  The females make nests in various places. The mason bee, Osmia (Megachilidae), which may be metallic green or blue, uses mud to make chambers for her eggs in preexisting cavities like hollow stems.

  Digger bees, Anthrophora spp. dig their nests in bare soil. Flight season is from February to June. Females have long hairs, scopae, on their hind legs for carrying pollen. To invite them to your flowers, leave a bit of uncovered soil.

  Leafcutter bees and Megachile spp. are slow fliers with heavy heads needed for cutting leaves to separate eggs in their nest.
  Frequently seen is the sizeable yellow-faced bumble bee, Bombas spp. they are easily identified due to the yellow strips on their black backs. Native bumble bees are unusual since they are social bees with queens and workers that live together.

  Cuckoo bees are brood parasites. Female cuckoo bees lay their eggs in another bee’s nest that has already been filled with nectar and pollen, sometimes killing the host bee’s egg.

  Most of a native bee’s life is spent in the nest, transforming from egg to adult, usually overwintering and pupating in the spring as an adult. They like to find a large patch of the same blooming plant for efficient nectar and pollen collection.

  Native bees and native plants have evolved together. There are 6500-8,000 native plants in California, and about 1,000 are native to Marin. They have evolved to survive our hot, dry summers and cold, wet winters. They are naturally suited to our climate, soil, insects, and animals. They resist pests and diseases.

  Since native bees emerge from their winter habitats at different times, they need flowering plants at all times of the year. The following are some native plants that feed them.

  

  Bumble bees find nectar on the blue blossoms of a California Lilac. Photo: Barbara Robertson

  California lilac, Ceanothus, spp. are early-flowering spring plants with blue flowers. They bloom from February to April and attract bumble, mining, digger, and masked bees.

  California poppy, Eschscholzia californica, is the state flower and blooms from early March to October. This bright orange flower produces pollen that attracts bumble, sweat, mining, and honey bees.

  Manzanita and Arctostaphylos spp. bloom from January to March. Bumble, digger, and mining bees are all attracted to the urn-shaped flowers hanging in clusters.

  Common Sunflower, Helianthus annus, attracts summer long-horned, cuckoo, leafcutting, and cactus bees from June to September.

  California aster Symphyotrichum chilense is a late-season bloomer from summer to fall and another good source of pollen and nectar.
  Coyote Mint, Monardella spp. blooms from May to August in many colors, attracting bumble bees, masked bees, and leafcutting bees, as well as butterflies.

  Studies show that native bees prefer native plants, but many non-native plants attract native bees as well. We care about bees because they are an indicator of environmental health. They feed a number of species, including humans, and they maintain our wildlands. Pesticides and herbicides will kill all bees.