Hummingbird & Bat Pollination
When we think of plant pollinators, we usually think of bees, butterflies and other insects, but in fact, hummingbirds and bats have become the primary pollinators of many species in the plant community. Hummingbird and bat-pollinated flowers have many contrasting characteristics. These flowers have adapted specialized features to attract their pollinators. In the economy of nature, bats and hummingbirds provide an important service to flowering plants, while the plants repay with a sugary treat.
Throughout the Americas, plant species have evolved flowers whose primary pollinators are hummingbirds. Such plant families include Acanthaceae, Asteraceae, Bromeliaceae, Gesneriaceae, Heliconiaceae, Loranthaceae, Rubiaceae, Zingiberaceae, and many others (Schoen, p 70).
Although hummingbirds visit a wide variety of flowers, many hummingbird-pollinated flowers share some general characteristics. The flowers tend to be tubular, bright red, orange or yellow in color, relatively odorless, and contain more concentrated levels of sucrose than other wildflowers to support their high energy needs (Schoen, p 70). They thrust their long, slender beaks into the flowers and suck up the nectar. In return, the hummingbirds brush against the pollen in one bloom and deliver it to the next.
Hummingbirds have adapted the unique ability to hover while feeding and can fly backwards and forwards. To hover, the hummingbird tilts its body and wings into a more vertical position. This causes the main flight feathers to push air downward instead of backward. The down stroke and up-stroke provide lift but not forward movement. On the down stroke, the wings are tilted so that they force air downwards and the bird upwards. At the end of the down stroke, the wings twist 90 degrees. This forces air downward on the upstroke as well. This effect creates only lift and no rotational movement to allow the hummingbird to be suspended almost upright in air. To...