The summer before my senior year of college, I spent my days in a ten by ten tent at the UW Madison Arboretum, surrounded by approximately 1000 yellow-jacket wasps. I’d lie on my back, notebook in hand, and carefully tabulate the comings and goings of each and every wasp in the colony. Some collected grasshopper legs and morsels of meat for their sisters to eat. Others shuttled to and from piles of leaves and paper, gathering building materials for their hive. The youngest of the group stayed behind to care for the larvae and guard the entrance to their kingdom.
In early summer when the prairie was still green, the colony numbered less than 100 and we humans felt safe enough to work without gloves or face coverings. By the time the goldenrod began to bloom, however, the family had swelled to more than 1000 members and the wasps gathered and built at a feverish pace. Eventually, the air turned crisp and the workers began to stumble and fade. The only generation of males was born and died, new queens were appointed, and soon, only they remained alive to weather the winter and carry the family tree forward into a new year.
It is said that one out of every three bites of food we eat is created with the help of pollinators. More than 80% of the world’s flowering plant species require pollinators to reproduce and these bees, butterflies, wasps, ants, and even bats are essential to the fruits, vegetables, chocolate, coffee, nuts, and spices that bring joy and sustenance to our lives.
There are more than 500 species of bees in Minnesota and 157 species of butterflies. Less well-loved, but equally important, are the wasps, which have a similar diversity and provide numerous beneficial services as well. In addition to pollinating food crops, trees, and native flowers, wasps also help to control pest insects and invasive species such as the emerald ash borer. In fact, the U.S. Department of Agriculture and U.S. Forest Service currently releases three species of parasitoid wasp in Minnesota as a biocontrol for emerald ash borer. Two species attack larvae under the ash bark and the other kills the emerald ash eggs. These tiny wasps are small like gnats and do not harm humans.
Unfortunately, many species of pollinators are declining due to loss of habitat and the use of insecticides, including neonicotinoids. One species of concern is the rusty-patched bumble bee (Bombus affinis), which is the official Minnesota State Bee. It was designated as a federally endangered species in 2017 and is one of the insects that the Minnesota Lawns to Legumes program is designed to support.
Happily, regular people like you and I can help to create pockets of biodiversity and protect pollinator species, simply by incorporating flowering native plants into our yards to provide blooms throughout the growing season. Flowering trees such as crabapple, plum, dogwood and basswood are important as well and provide a vital source of early season nectar for butterflies, bees and wasps.
There are hundreds of pollinator-friendly native plants to choose from for your yard, but some species are pollinator powerhouses. For example, I have a virgin’s bower (Clematis virginiana) that climbs over a trellis on the edge of our garden and literally buzzes with activity in the middle of the summer when tiny white flowers appear on the vine. It attracts dozens of species of bees and wasps, including great black wasps (Sphex pensylvanicus), which look fearsome but are actually quite docile. Other powerhouse species include bee balm (Monarda fistulosa), wild rose (Rosa blanda), and asters.
There are also specialist insects, such as the monarch butterfly, that have very specific dietary needs. To support monarchs in your yard, choose from one of eight species of milkweed that are native to Minnesota, including common (Asclepias syriaca), whorled (Asclepias verticillata), butterfly (Asclepias tuberosa), purple (Asclepias purpurascens), poke (Asclepias exaltata), green comet (Asclepias viridiflora), showy (Asclepias speciose), and swamp milkweeds (Asclepias incarnate).
To learn more about planting for pollinators, including what to plant, how to get started, and where to find native plants for your yard, register for a free webinar on Thursday, March 2, 6-7:30pm. Learn more at tinyurl.com/pollinators2023.
For a more in-depth dive into pollinators, you can also check out the Best Practices for Pollinator Summit on March 7-9, featuring dozens of top-notch presentations by conservation experts.