Last month, in the week of June 15, we celebrated National Pollinator Week. There has been significant discussion about the challenges pollinators (especially bees and monarch butterflies) face in our world. Pollinators, both native (native bees, flies, wasps, hummingbirds, etc.) and non-native (honeybees) provide an essential service to our lives and ecosystems (bats also pollinate plants, but we do not have any fruit-eating bat species in Arlington). Not only do they provide us with one third of the food we eat through the reproduction of flowering plants and their seeds, but they also keep our flowering plants going in our natural world.
Alonso Abugattas, Arlington’s Natural Resource Manager, recently spoke about different pollinators like beetles and bees, and touched on some of the limitations of focusing only on milkweed for pollinator value, so it’s time to talk about the importance of trees in a pollinator’s life cycle.
Leaves: Baby Food for Many Pollinators
While this blog will also address the value of flower nectar, the real meat and potatoes for many pollinators, especially butterflies and moths, lie in the leaves. Where monarch butterflies eat primarily milkweed leaves, many other species are dependent on tree leaves for their early stages of development. For example, the spicebush swallowtail caterpillar (Papilio troilus, Pictured above right), only feeds on spicebush (Lindera benzoin) and sassafras (Sassafras albidum), both native understory trees. The zebra swallowtail (Eurytides Marcellus), only feeds on young pawpaw (Asimina triloba) leaves.
Many species are not as picky as the aforementioned species, and feed on a wide variety of trees. Our state insect, the tiger swallowtail butterfly (Papilio glaucus, pictured below right), finds a host on tuliptree (Liriodendron tulipifera), black cherry (Prunus serotina), sweetbay magnolia (Magnolia virginiana), and many other native host plants.
Douglas Tallamy, in his research on lepidoptera (moths and butterflies) identified a list of plant species with the highest value to this group of insects.As mentioned in an earlier blog post, one of our most common tree species, the oaks (Quercus species), are the host of the most lepidoptera in the region. This makes oaks some of the most valuable pollinator plants to plant around. With all their other values, they really are an extremely valuable species to plant and preserve around here. Closely followed by the oaks are native cherries, like black cherry (Prunus serotina), willows (Salix), birches (Betula) and poplars (Populus). Keep in mind that even though there are non-native species in these plant groups, the native version provide the greatest benefit to our pollinators.
Flowers: Nature’s Source of Nectar
What’s more popularly known as food for pollinators is the nectar from flowers. Nectar provides immediate energy for all species in what we know of as pollinators, from bees turning it into honey, to hummingbirds feeding from buckeye flowers mid-air (pictured left). Even here, not all flowers are created equal in pollinator value, but research has highlighted some high-value trees here, as well.
Some of the species with great nectar benefit include some already-popular landscape trees, such as Red Maple (Acer rubrum), Eastern Redbud (Cercis Canadensis), American linden (Tilia americana) and Blackgum (Nyssa sylvatica). Also noted in some of the research are smaller trees with human food value, as well, such as American Plum (Prunus americana), Persimmon (Diospyros virginiana), and Black Cherry (Prunus serotina). All of the above species, when given the right space, work well in Arlington.
Let’s help make Arlington a home for our pollinators. Plant and protect our native plants, and work to provide a great habitat for all.
- Pollinator Partnership: http://www.pollinator.org/pollinators.htm
- Native plants of Northern Virginia: http://www.plantnovanatives.org/
- What to plant for Butterfly and moth benefit: http://www.bringingnaturehome.net/what-to-plant.html
- West Virginia handbook for pollinators (page 82 has a list of woody species for pollinators): http://www.xerces.org/wp-content/uploads/2009/11/WVPH-SEC.pdf
- What species attract what pollinators: http://www.ree.usda.gov/ree/news/Attractiveness_of_Agriculture_crops_to_pollinating_bees_Report-FINAL.pdf
This post was edited on 7/17/2015 to reflect corrections to species pictured.