Req 3 — Pollinators at Work

Pollination is the transfer of pollen from the male part of a flower (anther) to the female part (stigma). Without pollination, most flowering plants cannot produce seeds or fruit. While some plants rely on wind or water, the vast majority depend on animals — especially insects — to move pollen from flower to flower.

Why Honeybees Matter

Honeybees are the world’s most important managed pollinator. A single honeybee colony can visit millions of flowers per day, and beekeepers transport hives to farms specifically to pollinate crops. In the United States, honeybees pollinate an estimated $15 billion worth of crops annually, including almonds, apples, blueberries, cherries, and melons.

How Bee Pollination Works

1. A bee visits a flower to collect nectar (its food source).
2. As the bee moves around the flower, pollen grains stick to its fuzzy body.
3. When the bee visits the next flower, some of that pollen rubs off onto the stigma.
4. The pollen grain grows a tube down to the ovary, fertilizing the ovule.
5. The fertilized ovule develops into a seed, and the ovary becomes a fruit.

Other Pollinating Insects

Honeybees get the most attention, but many other insects are critical pollinators:

• Bumblebees — Larger and fuzzier than honeybees, bumblebees are especially effective at pollinating tomatoes and peppers through “buzz pollination,” where they vibrate their bodies to shake pollen loose.
• Butterflies — Attracted to brightly colored flowers, butterflies carry pollen on their long legs as they drink nectar.
• Moths — Night-flying moths pollinate pale, fragrant flowers that open in the evening, like moonflowers and evening primrose.
• Beetles — Some of the oldest pollinators on Earth, beetles pollinate magnolias, water lilies, and other ancient flower types.
• Flies — Hover flies and other species pollinate many wildflowers and some crops.
• Wasps — While less efficient than bees, wasps pollinate figs and several other plants.

Non-Insect Pollinators

Some plants rely on animals other than insects:

• Hummingbirds — Pollinate tubular red and orange flowers.
• Bats — Pollinate hundreds of tropical plants, including agave and some cacti.
• Wind — Grasses, corn, wheat, and many trees are wind-pollinated, producing huge amounts of lightweight pollen.

Threats to Pollinators

Pollinator populations face serious challenges, including:

• Habitat loss — Development and farming eliminate the wildflower meadows and nesting sites pollinators need.
• Pesticides — Certain insecticides, especially neonicotinoids, can kill bees or impair their ability to navigate.
• Disease and parasites — The Varroa mite has devastated honeybee colonies worldwide.
• Climate change — Shifts in bloom timing can create mismatches between when flowers open and when pollinators emerge.

Now that you understand how plants reproduce with the help of pollinators, it is time to learn what else plants need to grow — and how soil makes it all possible.