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It might sound crazy, but I want more insects in my yard

“[H]umans would last only a few months if insects were to disappear from Earth. It is remarkable, then, that our cultural relationship with insects is not one of awe and appreciation, but one of disgust and animosity.”

— Douglas Tallamy, “Nature’s Best Hope,” 2019

Do you value the insects in your garden and yard? Do you want to increase the number of insects in your garden and yard? Of course, it depends on what kind of insects I’m talking about.

According to Douglas Tallamy, one of the most important ways we can support biodiversity and contribute to a balanced ecosystem is to pay attention to the number of caterpillars, butterflies and moths we have in our landscape, and make gardening choices that will increase their populations.

Caterpillars are particularly important in order to support birds because they (not earthworms) make up 96% of the birds’ diet while raising their young. It’s amazing to know that parent birds must bring food back to their nest of 3-5 babies between 120-150 times every day for two weeks. That’s a lot of caterpillars!

Birds depend on caterpillars for their young because these insect larvae are high in fat and have twice as many carotenoids as other insects. Carotenoids are healthful pigmenting compounds that are found in some of our favorite vegetables: yams, spinach, tomatoes, carrots, beets, kale, peppers and melon, among others. Carotenoids contain lots of antioxidants and strengthen the immune system. People benefit from them by eating vegetables, and birds benefit from them by eating caterpillars.

To effectively support and monitor caterpillars in our garden and yard, it’s helpful to understand the lifecycle of Lepidoptera. They all go through complete metamorphosis consisting of four stages: eggs, larva, pupa and adult. Butterflies and moths spend most of their lives as caterpillars, feeding voraciously on their host plant and shedding their skin several times to accommodate their rapidly increasing size.

At the end of the larval stage, caterpillars drop to the ground in search of leaf litter, twigs or dead plant stems to build a chrysalis. After emerging from their cocoon, females will mate once and then return to the host plant to lay eggs and die. Most Lepidoptera species live only a few weeks, but some live up to 18 months. Depending on the species and their habitat, butterflies and moths produce one or two generations per year. Some may overwinter as a larva, pupa, eggs or an adult.

To support Lepidoptera in our gardens and yards, we need to make water and shelter available to them throughout the year. Terracotta plant saucers, bird baths, fountains and pond edges provide a place for butterflies to drink and bask in the sun. Rather than installing built butterfly houses in the yard, Tallamy suggests placing a few decaying logs or rocks with crevices around for shelter, instead. Keeping some leaf litter and plant stalks in the yard provides a place for the insects to build cocoons and offers them protection over winter.

Speaking of protection, Tallamy points out that our porch lights and security lights are devastating for night-feeding moths, which are so mesmerized by the brightness that they abandon their foraging and often die by beating themselves against the lamp. He suggests installing sensors on outdoor lights to help keep moths safe.

Planting native host plants for Lepidoptera provides the food they need, a place for them to lay eggs and a nursery for caterpillars. I’ve written in previous columns about specific native plants that support local wildlife, including caterpillars and moths. Here’s a list of some of my top choices for native trees, shrubs and herbaceous plants, and the number of Lepidoptera they support. Specific native plant species are adapted for wetter/drier and lower/higher elevation habitats in our area. (For more information, see www.nwf.org/NativePlantFinder.)

Trees and shrubs: willow (Salix), 312; chokecherry (Prunus), 240; oak (Quercus), 200; blueberry (Vaccinium), 130; raspberry (Rubus), 96; rose (Rosa), 94; blueblossom (Ceanothus), 93; service berry (Amelanchier), 81; hazelnut (Corylus), 71; dogwood (Cornus), 58; California wild grape (Vitis), 55; kinnikinnick/manzanita (Arctostaphylos), 51; oceanspray (Holodiscus), 39; rhododendron and azalea, 32; elderberry (Sambuca), 32; and snowberry (Symphoricarpos), 32.

Perennials: strawberry (Fragaria), 69; lupine, 55; goldenrod (Solidago), 49; sunflower (Helianthus), 41; violet (Viola), 27; willowherb (Epilobium), 25; Indian paintbrush (Castilleja), 24; geranium, 21; beardtongue (Penstemon), 18; evening primrose (Oenothera), 17; columbine (Aquilegia), 10; clematis, 9; phlox, 9; and iris, 8.

Choosing native plantings that bloom at different times will help provide pollen and nectar from spring until fall for native bees and wasps.

I’m excited to add more natives to my landscape and watch what happens. I recently participated in a free, ongoing web class offered by the OSU Extension Service on how to use a program called iNaturalist to help identify and monitor the number of native Lepidoptera and Hymenoptera I have on and around my native plants, as well as the number of native birds I have in my landscape. This is a visual way for me to keep track of my goal to increase biodiversity in my yard. Here’s how iNaturalist works:

Open an account on your computer at www.inaturalist.org or download the iNaturalist app to your smartphone. Once I opened an account on my computer, I joined OSU’s iNaturalist Project for Master Gardeners at www.inaturalist.org/projects/observations-by-oregon-s-master-gardener-volunteers, which was set up for gardeners in our area to share observations of wildlife: mammals, birds, reptiles, amphibians, arthropods, worms, mollusks, plants and fungi.

On the project page, I can upload pictures of native butterflies and bees (or any wildlife), along with information about when and where the insects were observed and other notes such as how many of the insects were seen at one time in a particular area. There’s also an option for uploading sounds if I want to identify and monitor native birds in my yard.

I can click on “Species name” for identification suggestions and “View” for more details about the top-suggested insect, either at the genus or species level. Once I’ve agreed with an ID for one of my insects, I can submit my observation for feedback from the OSU iNaturalist project community. The picture and information is added to my personal Observations page, so I can keep an ongoing inventory of the insects and other wildlife I see, and also contribute to a statewide project to track wildlife.

After reading “Nature’s Best Hope,” I’m looking at my yard and garden in a different way. I’m certainly looking at the role of insects in my yard with renewed respect.

Tallamy writes, “We simply need to include ecological function in our land management plans to keep the sixth mass extinction at bay.” It’s truly remarkable that tiny insects are our important allies in accomplishing such a monumental task.
