Module 3

The Other Half of the Partnership: Pollinators

Purpose:

• To understand the characteristics of pollinators that make them uniquely suited to the task of pollination

Background

In various parts of the world bats and certain birds, such as hummingbirds, sunbirds, sugarbirds, honeycreepers, and brush-tongued parrots, serve as pollinators to certain plants. For example, many species of bats live in tropical areas where they pollinate fruit-bearing plants such as the banana tree. However, insects — especially beetles, ants, flies, bees and wasps, butterflies and moths — are the predominant animal pollinators.

The study of the life cycle and habits of each of these insects is fascinating in and of itself. However, the focus of this curriculum is on the role of pollinator carried out by these insects within the ecosystem. We have further narrowed our focus to those North American pollinators that are most important to the foods we eat and delight us with their beauty: managed and native bees and butterflies and moths. These insects have physical characteristics that make them extremely efficient in locating flowers and transferring pollen from one flower to another.

Flower fly. Photo by Andy Neill.


Honey bees.


Honey bee with full pollen baskets.
Photo by Suzanne DeJohn/NGA.

For example, The antennae of bees are very sensitive to touch and odor stimuli. Bees can differentiate between hundreds of different aromas. Honey bees also rely on their sense of vision to locate flowers. Using 2 compound eyes that detect color, shape and movement and three simple eyes that detect light, they see colors in the spectrum ranging from ultraviolet to orange, but do not see red.

Many flowers have shiny patches of ultraviolet on their petals called bee guides or nectar guides. Like airport runway lights, these ultraviolet regions guide the bees to the nectar.

The proboscis of the honey bee is a long, slender, hairy, tube-like tongue that acts as a food canal to bring the liquid food (nectar, honey, and water) to the mouth. It allows the bee to access nectar in the flower that it could not otherwise reach. When in use, the tongue moves rapidly back and forth while the flexible tip performs a lapping motion.

Bees have lots of little hairs on their body. Even their eyes have hairs. Pollen sticks to the hairs while the bees are visiting the flowers. A furry little bee wiggling around inside the flower picks up a lot of pollen. After getting pollen on their body hairs, the bees may move some of it to a special area on their hind legs called pollen baskets. Foraging bees returning to the hive often have bright yellow or greenish balls of pollen hanging from these pollen baskets.

Butterflies and moths are classified together in the order Lepidoptera¹ due to the fact that every part of their body, from their wings to their feet, is covered by thousands of delicate scales — scales that can collect pollen. Butterflies and moths usually differ in four ways:

1. Most butterflies fly only during the day, while most moths fly at dusk or at night.

2. Generally, butterflies fold their wings straight up over their bodies and moths spread their wings flat when resting.

3. The antennae of butterflies have bare knobs at the ends; the antennae of most moths are either hair-like or plume-like and end in a point.

4. Most moths have a plump body when compared to the thinner body of butterflies.

In one respect, butterflies have a Dr. Jekyl/Mr Hyde character. During each of the 4 stages of development (egg, larva, pupa, adult) the insect looks and lives in a new way. In the larva stage, as a caterpillar, its voracious appetite makes it very destructive of crops. Caterpillars of different kinds of butterflies look quite different but the colors and markings of the caterpillar do not resemble the adult butterfly they become. In the adult stage butterflies are harmless and are helpful in pollinating flowers.

The antennae of butterflies and moths are used to smell and may also be used for hearing, according to some experts. A butterfly tastes with its feet. The sweet taste of flower causes the insect to uncoil its probiscis, which it uses to suck up nectar and other liquids. Butterflies also have large compound eyes on the sides of their head that detect movement and the color patterns of flowers and other butterflies. Certain butterflies, such as the monarch butterfly, are migratory and may go through a different stage of development at different points along its migratory route.

Newly emerged atlas moth.


Luna moth. Photos by Suzanne DeJohn/NGA.

¹ The name Lepidoptera comes from two Greek words, lepidos (meaning scale) and pteron (meaning wing).

References

Honey Bees & Pollination, Lesson 2.4, Africanized Honey Bees on the Move, Africanized Honey Bee Education Project, University of Arizona

Pollinators & Their Preferred Flowers, Information sheet 23, Africanized Honey Bees on the Move, Africanized Honey Bee Education Project, University of Arizona

Pollination: The Art and Science of Floral Sexuality by Nancy C Pratt and Alan M. Peter, ZooGoer, July/August 1995.

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