Friday 5, Lepidoptera Keystone Species
For many of us there may not be enough room on our property to plant a forest of maple or hickory, or produce a savanna including several oak trees.
Many people don’t plant birch on their property anymore and most try to get rid of their Populus genus including Poplars, Aspens and Cottonwoods, or Willows (Salix), because they are considered “messy”.
When it comes to the Prunus genus you may be very familiar with cultivated varieties, but they don’t provide as much support as the native plants that are biologically suited to Ontario lepidoptera. Remember the point about caterpillars being mandibulate (chewing) insects. When it comes to any of these keystone species they are looking for their tasty native options.
So how can at least some of these keystone species be incorporated into a smaller backyard?
Let’s take a look at the top 5 first.
All of the oaks (Quercus) are in the 50-80’ range.
The willows (Salix) vary from 1.5’ to 60’ so you have a lot of choice depending on where you want to plant them. Some are also quite pretty.
Genus Prunus also has a lot of variety from 1-80’ tall. Also many have delicious fruit for you, or you can share with the birds.
The birch (Betula) trees also have a huge range from 12-130’ tall.
Genus Populus definitely contains the tallest trees with Cottonwoods topping out at 190’.
These are the 5 species that play a key role in their contribution to the local food webs.
How can we incorporate them in a landscape?
Many people plant a tree in the front yard - for the longest time it was a red maple because they were fun. Red maples (Acer rubrum) grow to be about 75’ tall. If we’re going to plant a 75’ tall tree in our front yard anyways (we did in our childhood home), why can't it be one of the Keystone species instead?
Oak trees definitely fit into that height range. Yes, oak trees have acorns, and acorns bring squirrels, and squirrels can chew into your attic. Life my friends, always finds a way. If you have no life in your little ecosphere I would be worried. Life around you supports your life. A stray squirrel in the attic or hail of acorns in a bumper crop year shouldn’t stop you from supporting a system that, in the end, supports you. If you have the space, plant the prime keystone species for Lepidoptera. The caterpillars will thank you!
Maybe your little patch of land can’t support a large tree. Neighbours may not want the shade, or you may want to get some sun in your front or back yard. Genera Salix (willows), Prunus and Betula (birch) have many options for you.
On the smaller side
The Heart-leaved Willow (Salix cordata) is only 3-12’ tall. That won’t crowd out the sun and it’s at home in very sandy sites.
The nectar and pollen attract many insects, especially bees including several Andrenid bees, who are specialist pollinators (oligoleges) of willows. The caterpillars of the Acadian Hairstreak, Striped Hairstreak, Viceroy, Red-Spotted Purple, Mourning Cloak and Compton Tortoiseshell feed on the leaves. Other insect feeders include the caterpillars of the White Underwing, Willow Leaf Miner, Little Willow Sister and many other moths.
The Ruffed Grouse, Northern Pintail, Mallard, and White-Crown Sparrow eat the buds or catkins. The Yellow Warbler, Warbling Vireo, Philadelphia Vireo, and Rusty Grackle use this willow for nesting sites.
Also the leaves of willows are consumed by some turtles, including Snapping Turtles (special concern) and Wood Turtles (endangered).
2. The Basket Willow (Salix purpurea) is 3-15’ tall and grows in a dense mound that is quite pretty.
The florets of willows are cross-pollinated primarily by bees and flies, including honeybees, cuckoo bees, mason bees, Halictid bees, Andrenid bees.
It feeds the larvae of the Lycaenidae and Nymphalidae families of butterflies and many moths.
Because it is densely branched and bushy it provides good cover for many kinds of wildlife and nesting habitat for several songbirds.
3. A Dwarf Birch (Betula borealis, Betula glandulifera, Betula pumila) gets to be 12-36’ tall and can take sandy soil and wet environments.
Several insects feed on birches including katydids and the larvae of different moths.
Chickadees, finches, and juncos feed on the buds and nutlets of birches as well as other songbirds.
4. In the Prunus genus, the Sandcherry (Prunus pumila) has a range of 3-10’ tall. White blossoms cover the bush in May and June followed by berries that the birds will love. Leaves turn a very pretty red in fall.
Nectar and pollen of the flowers attract bumblebees, Andrenid bees and Halictid bees. Butterflies and skippers may infrequently visit the flowers for nectar. Caterpillars of moths such as the Bold-Based Zale and Clouded Veneer, as well as Red-Spotted Purple and Coral Hairstreak butterflies feed on Prunus.
Cherries are a favorite source of food for many songbirds and some upland gamebirds, including Wild Turkey, Eastern Bluebird, Northern Cardinal, Gray Catbird, Eastern Kingbird, American Robin, and Cedar Waxwing.
5. If you want a fruit tree the American Plum (Prunus americana) is 15’ tall. This hardy fruit tree has showy, fragrant white blossoms in spring and then produces delicious plums with pinkish/red exterior and yellow flesh. Great for preserves.
Nectar and pollen attracts honeybees, bumblebees, Little Carpenter bees, Cuckoo bees, Halictid bees, and Andrenid bees.
Many insects feed on the wood, bark, sap, leaves, buds, flowers, and fruits.
The fruit is a bit big for most birds but they will occasionally peck at them and the fruit is eaten by foxes.
Basket Willow (Salix purpurea) Picture taken by Álvaro Izuzquiza
No matter where you live there is an option for you from the 5 Keystone species. And by planting some of these in your yard you instantaneously make your ecosphere a splendid place. Birds, bugs and bees make life better.
