The first blooms of spring have me thinking of pollinators. What comes to mind when you hear the word “pollinator”? Butterflies, moths, flies, birds and even bats are important pollinators, but the one most people probably think of is the honey bee, Apis mellifera.
The honey bee is currently used to pollinate more than a third of crop plants and without them the world food supply would have problems. Unfortunately, these bees have problems of their own. Imported from Europe, they are being plagued by a variety of diseases and pests such as mites. Widespread pesticide use puts even more pressure on already struggling hives. Native bumblebees are also in decline from disease and habitat loss.
The future of agriculture may rely on nurturing healthy populations of native bees and other pollinators. Most native bees are solitary and the current model of trucking hives from crop to crop, following the blooms, is not practical for these species. Many native bees are tiny and look more like flies than the fuzzy, black and yellow striped icon most people hold in their mind. Instead of making honeycombs, native bees live in a variety of habitats. Some dig labyrinths into loose dirt, leaving an egg on a ball of pollen in each chamber before flying off and starting a new nest. Some commandeer old beetle tunnels in dead wood.
Different groups of bees are best for different crops. Squash bees feed their offspring only on the pollen from cucurbits. The blue orchard bee is a promising replacement for honey bees in almond and other orchards. Almond crops require the highest number of beehives per acre for a good yield. With blue orchard bees, as few as 400 female bees per acre can do the job of 10,000 to 25,000 honey bees. An active native bee population can also help imported honey bees pollinate crops more thoroughly. Sunflower crops with native bee activity had more than double the seed set of crops without, because the competition made the honey bees switch flowers more often and spread pollen more widely. Other native bees help wind pollinated crops. Tomatoes set more and heavier fruit with buzz pollinating bees (like bumble bees) around.
Habitat plants to host native pollinators are similar to what you’d plant to encourage beneficial insects. Bees need a constant source of nectar and pollen, so wildflower mixes should have something blooming year round. To increase pollination of crops, it is best to have flowers that bloom right before and after the crop so that the bees are more likely to forage in your crop. Dead heading or mowing wildflower stands while the crop is in bloom may help drive more bees into your field.
For nesting, there should be un-tilled areas of bare, loose soil for the ground nesting bees and woodpiles for tunnel nesters. Some people make bee condos by drilling holes in blocks of wood or bundling together hollow reeds or bamboo. Bumblebees like to use abandoned rodent holes, bunchgrasses, and low growing shrubs. The Xerces Society has regional information on native pollinators and the local plants that host them.
In recognition of the role that pollinators play in the health of people and ecosystems, the US Senate designated a National Pollinator Week in 2007 and some states followed suit in recognizing a week of pollinator awareness. This year National Pollinator Week is June 20-26 and the Pollinator Partnership is urging every state to observe its own pollinator week this year. To help, contact your governor expressing your support for pollinator awareness. Or you can act even more locally by organizing pollinator education events in your community, like festivals, garden tours, workshops, lectures, and photography contests.
-Alia Tsang
Many gardeners think ‘ladybugs’ when they want to go after plant pests. When I have a chance, I try to pitch the benefits of green lacewing instead. Especially from late spring through early fall, lacewing eggs on cards are, in my experience, more reliable and versatile.
