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Archive - October 2016
Trees are all around us. We see them so often that we may not even think about them. In fall, we might notice them more when their leaves change colors. Trees are important every day, though, to humans and wildlife. One of the many benefits of trees is the food that they provide. Trees and their products can be used for food by a huge number of wildlife species. Food from trees is available all year. When animals feed on trees and their products, pieces of the tree are digested and become a part of the animal’s body to be used for energy, structure or other functions. So what part of a tree became a part of me? Let’s find out by looking at some examples.
Fruits
If you are a downy woodpecker (Picoides pubescens), white-breasted nuthatch (Sitta carolinensis), tufted titmouse (Baeolophus bicolor), brown thrasher (Toxostoma rufum), eastern chipmunk (Tamias striatus), white-footed mouse (Peromyscus leucopus), southern flying squirrel (Glaucomys volans), mallard (Anas platyrhynchos), wild turkey (Meleagris gallopavo), white-tailed deer (Odocoileus virginanus), eastern gray squirrel (Sciurus carolinensis), wood duck (Aix sponsa), raccoon (Procyon lotor), certain moth larvae or blue jay (Cyanocitta cristata), it could be acorns (fruits)!
Acorns are the fruits of oak trees. They contain a seed of the tree enclosed by a protective coating and covered with a thick cap. Acorns are full of nutrients. They have proteins, carbohydrates, fats and minerals. They are big and easily eaten. They can also be found on the tree or on the ground around the tree for a long period of time. Some animals store acorns to eat at a later time.
Many other trees produce fruits used for food by animals, too. They include the wild black cherry (Prunus serotina), hickories (Carya spp.), persimmon (Diospyros virginiana), red mulberry (Morus rubra), hackberries (Celtis spp.) and crab apples (Malus spp.).
Nectar or Pollen
If you are a bumble bee (Bombus spp.), carpenter bee (Xylocpoa spp.), sweat bee (Trigona spp.), tiger swallowtail butterfly (Papilio glaucus), ladybird beetle (Family Coccinellidae) or one of our other pollinating insects, it could be nectar or pollen!
Nectar and pollen are produced in the flowers of trees. Nectar is a sweet liquid. In flowers, it is used to attract pollinators. These animals pick up pollen as they feed on the nectar and transfer the pollen to other flowers as they move about. Pollen contains male reproductive structures. The pollinating animals help the plants to produce seeds. Many animals feed on pollen. Pollen contains carbohydrates and protein. Nectar is mainly made of sugars (carbohydrates) but also contains some proteins and other nutrients.
Many trees in Illinois produce flowers. Examples that are especially important to pollinators include redbud (Cercis canadensis), flowering dogwood (Cornus florida), crab apples, catalpa (Catalpa speciosa), tulip tree (Liriodendron tulipifera) and black willow (Salix nigra). Some animals, such as aphids (Family Aphididae), Japanese beetles (Popillia japonica), cedar waxwings (Bombycilla cedrorum) and northern cardinals (Cardinalis cardinalis), feed on the entire flower.
Woody Parts
If you are a bark beetle (Family Scolytidae), wood-boring beetle (Order Coleoptera), termite (Order Blattodea), eastern cottontail (Sylvilagus floridanus), American beaver (Castor canadensis) or white-tailed deer, it could be bark, twigs or the other woody parts of the tree!
Sugars, starches and proteins are the major nutrients in woody tree parts, and they are available year-round. Some animals, like the American beaver, feed mainly on the bark. In the spring and fall, about half of the beaver’s diet is woody material. In the winter, though, its diet is composed almost entirely of woody items. Eastern cottontails tend to feed on bark in the winter when conditions are harsh and other food sources are not available. Most bark beetles live, feed and reproduce in dead, weakened or dying trees. Termites eat dead trees.
Tree Buds
If you are a northern cardinal, cedar waxwing, American goldfinch (Spinus tristis), white-tailed deer, eastern fox squirrel (Sciurus niger) or eastern cottontail, it could be tree buds!
A bud is an undeveloped plant shoot. There are three types of buds: those that produce leaves and stems; those that produce flowers; and those that produce leaves, stems and flowers. Buds are present on most trees in some stage of development throughout the year. They are nutritious, plentiful and easy to find.
Tree Leaves
If you are a tiger swallowtail larva, zebra swallowtail larva (Eurytides marcellus), hackberry butterfly larva (Asterocampa celtis), leaf-mining insect larva, Japanese beetle or katydid (Family Tettigoniidae), it could be tree leaves!
Leaves are not as nutritious as the other tree parts, and in Illinois they are available as a food source only part of the year. A few mammals in Illinois eat tree leaves, but not as the main portion of their diet. Some insects regularly feed on leaves, however. Leaf-mining insect larvae live in a leaf as they eat it. They are protected from predators by doing so. You can see where they have moved in the leaf by the tunnel pattern that appears on the leaf. Most leaf-mining insects are moth larvae (Order Lepidoptera), sawfly larvae (Order Hymenoptera) and fly larvae (Order Diptera), but some beetle larvae (Order Coleoptera) use this feeding method, too. Butterfly larvae, such as those of the tiger swallowtail, zebra swallowtail and hackberry butterfly, also eat tree leaves. The fall webworm moth’s larvae (Hyphantria cunea) make a webbed nest in trees in which they feed on leaves.
Sap
If you are a yellow-bellied sapsucker (Sphyrapicus varius), ruby-throated hummingbird (Archilochus colubris), ant (Family Formicidae), red admiral butterfly (Vanessa atalanta), comma butterfly (Polygonia comma), mourning cloak butterfly (Nymphalis antiopa), question mark butterfly (Polygonia interrogationis), hackberry butterfly or many native bee species (Order Hymenoptera), it could be sap!
Tree sap is a liquid that usually flows inside the tree. There are two types of sap. Sap that is flowing up the tree from the roots contains mainly water, minerals and nutrients. Sap flowing from the upper parts of the tree to the roots has water, sugars made by the leaves and other chemicals. If there is a crack or other opening in the tree, sap sometimes escapes from the inside of the tree. Butterflies, bees and ants are among the species that feed on sap. The yellow-bellied sapsucker has a double purpose when feeding on sap. This bird drills rows of tiny holes in tree bark where sap can escape. It eats the sap, but it also comes back again and again to feed on insects that come to eat sap. You are a sap-eater, too, if you eat maple syrup!
Roots
If you are a cicada larva (Order Hemiptera), clearwing moth larva (Family Sesiidae) or aphid, it could be roots!
Tree roots are usually underground, but some trees have at least some of their roots above the surface of the soil. If that is the case, they may be eaten by small mammals. Underground roots are used as food by several species. Cicada larva feed on tree roots for many years before converting to the adult insect. Some aphids are developed to feed on underground roots.