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Archive - November 2019

An adaptation is a feature that helps a living thing survive. There are many types of adaptations, and color is one of them. These are some examples of animals and plants in Illinois that use coloration as an adaptation.

Fishes are often white or light-colored on their belly region and dark on their back. When they are swimming, the white belly makes them seem to blend in with the sky to something that is below them in the water. When seen from above, their body color allows them to match the color of the water or the bottom of the water body. So, a potential predator from above or below could be fooled by the fish’s coloring. It can also help the fish if it is a predator, by allowing it to hide on the bottom or at the water’s surface and swim quickly to catch prey that may not notice it.

The red squirrel (Tamiasciurus hudsonicus) shows the same sort of coloration. When seen from above its red back fur and tail may blend in with the pine needles or leaves on the forest floor where it searches for food.  A predator, such as a hawk, might have a hard time seeing the squirrel. The red squirrel’s belly is white. When in a tree, the squirrel’s belly may be hard for a predator to see it from below against the sky. However, red squirrels spend a good deal of time on the ground and in a tree cavity, so the survival value of the white underside may not be that great.

The young (fawn) of a white-tailed deer (Odocoileus virginianus) has red-brown hair with white spots on the back and sides. As a fawn often rests by lying down in wooded areas or tall grasses, the spots help to hide it from sight in these areas by showing a broken pattern, like that of sunlight broken up by leaves in the forest or grasses. The fawn’s behavior of not moving much while lying down also helps it to avoid detection. The spots are no longer present after the fawn molts for the first time, with its summer hair being replaced by the gray-brown winter coat.

Some animals can change color. The gray treefrog (Hyla versicolor) changes color to match its background. It can be for protective coloration, but it can also be to help it modify its body temperature. As an amphibian, the body temperature of this animal is mainly controlled by its environment. By darkening its skin color, it can absorb more heat faster, warming the body and making movement easier.

Animals like bees and striped skunks (Mephitis mephitis) have distinctive colors that can warn other animals to stay away. The yellow stripes, usually with alternating black or brown stripes, of bees are a reminder to an animal that has tried to eat one that doing so again is not a good idea. The black-and-white colors of a striped skunk are easy to see and remember. It also uses behaviors, such as raising its tail and stamping its feet, to tell other animals to stay away. If you have been sprayed with the foul-smelling skunk scent, you will easily recognize and avoid a skunk when you see one!

Many bees and wasps have a similar color pattern that acts as a protective device for the entire group. A predator that has had a bad experience with one of them, may avoid all of them in the future.

Some animals that are harmless gain some benefit from having coloration that is like those of animals that may sting or bite. The hover fly has a color pattern like that of a bee. It is harmless, though. If a predator has been stung while trying to eat a bee, it may remember that color pattern and avoid bees or anything that looks like them.

Eye spots on the wings of moths and the body of some caterpillars can be used to frighten small birds that may think that the “eyes” are those of a cat or hawk. The eye spots can also make a moth look bigger than it is. Two moths that use this technique in the adult form are the polyphemus moth (Antheraea polyphemus) and the Io moth (Automeris io).

The American bittern (Botaurus lentiginosus) lives and nests along the shore of marshes where cattails and other vegetation grow. Many of these plants are tall, thin and grow close together. The markings on the underside of the bird are also long and thin. It blends in well with the plants. It may also point its beak to the sky and stand still, further adding to the deception.

The long-eared owl (Asio otus) has colors in a pattern that looks something like tree bark. It perches and roosts in trees and is difficult to see when close to the tree’s trunk.

This common true katydid (Pterophylla camellifolia) is colored and shaped like a leaf. When it is not moving on a branch, it really does appear to be a leaf. Predators that hunt by sight have a hard time finding it.

Many wildflowers are brightly colored to attract pollinators. They need the pollinators to move their pollen for reproduction. The bright colors tell pollinators that the flowers now have pollen and nectar available for them to eat and use to feed their young. Different colors may attract different pollinators. Bees often visit blue or purple flowers. Ruby-throated hummingbirds (Archilochus colubris) visit red, pink and similarly colored flowers. Butterflies are attracted to orange, yellow, pink and red flowers. Flower shape is important in attracting specific pollinators, too.

Brightly colored fruits attract birds. The birds eat the fruits, including the seeds. The seeds pass through the digestive tract of the bird and are expelled in the bird’s waste materials. In this manner, the plant uses the birds to move its seeds to new locations for growth.

In the mating season, some male animals are more brightly colored than usual. Their coloration can be used to communicate that they are ready to mate. The colors can also be used to tell other males that this territory is taken. The male wood duck (Aix sponsa) is much more colorful than the female during the breeding season, yet it is about the same color as the female in the fall of the year.

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