Archive - October 2016

 

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.

 

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.

 

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.

 

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.

 

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.

 

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!