The creepy, crawly insects that rummage through our soils fascinate me. Life in our soils is easy to overlook, as it goes unseen. But the importance of our soil pollinators cannot be overstated. Pollinators in the soil? Yes! It is true that soil animals maintain soil structure, improve water infiltration, enhance nutrient content and plant productivity and act as predators of many organisms and food for others. But many soil insects serve as pollinators as well.
My favorite examples of soil pollinators include the ground nesting insects such as bees and wasps and, of course, the beetles. Most of our Colorado native bees are solitary and nest in the ground. These bees will dig a long tunnel, similar to our well-known prairie dogs, that will branch off and have small chambers (a.k.a. brood cells) that will hold larva. These pollinators require sunny locations that are not likely to flood. Ground nesting wasps dig similar small tunnels but are more often solitary holes than the branching tunnels of the bees.
Beetles, such as the Solider Beetle are critical pollinators as well as predator control for your plants. The larvae of the beetles live in the soil and leaf litter but often visit the plant in search of other insect eggs or aphids and then the beetle itself spends its life moving from flower to flower, pollinating along the way.
We should concentrate on the soils in and around our gardens. If we have healthy soil, we will improve habitat for our soil pollinators and therefore facilitate a healthy plant ecosystem without the use of pesticides and herbicides. Best practices for the health of your yard and garden soils and their beneficial soil insects include:
a) minimizing disturbance of the soil,
b) maximizing continuous living root systems and biodiversity as much as possible, and
c) providing a simple bare spot or a small sand pile will assist our ground dwellers with building their homes.
Composting, especially when you add a banana peel or other non-citrus fruits, will also feed your pollinating wasps, encourage them to develop a nest or ground tunnel and pollinate nearby flowers as well. Wasps tend to be territorial so by placing your compost away from those areas of your lawn that you inhabit, you will keep yourself out of their way, and they will still visit your nearby garden.
You can “scout” out your own garden soils and plants to discover what natural pest control insects and ground pollinators you are lucky to have. Check out https://xerces.org/sites/default/files/2018-05/17-037_01_Beneficial-Insect-Scouting-Guide-SOIL-2017-037.pdf and https://xerces.org/sites/default/files/publications/19-061.pdf which both provide you guidance in identifying and understanding the insects and their roles in your garden.
Other useful resources include:
· “Life in the Soil: A Guide for Naturalists and Gardeners” by James B Nardi (2007)
· “State of Knowledge of Soil Biodiversity: Status, challenges and potentialities Report” by FAO, ITPS, GSBI, SCBD and EC (2020)
· “Beneficial Insect Habitat: Assessment Form and Guide” from Xerces Society
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*Interested in joining the Pollinator Habitat Group or other Inquiries, please contact Cindy Linafelter, Cynthialinafelter@gmail.com.