Identifying, Attracting, Feeding, and Building Pollinator Nesting Sites

by Pat Allen, EMG

Caring about pollinators begins with understanding them, their lifecycle, their habitat needs, and the threats they face. Only then can you develop a strategy for helping them. After you identify the pollinators you want to attract to your garden you then begin selecting their food, water, and nesting materials.

Why would we want to go to all this effort?

Because pollinators are essential for one third of all food is pollinated, the evolution of wildlife and native plants are intertwined, and pollination is the plant’s way of reproduction: Seventy-five percent of plants rely on animals for pollination, whereas, twenty-five percent of plants depend on the wind to carry pollen.

The anatomy of a flower has evolved to where both insects and plants benefit from the relationship. Most flowers produce nectar which is a sweet food substance that attracts insects such as bees, butterflies, and hummingbirds. While insects are searching flowers for nectar, they inadvertently collect pollen from the male flower parts, known as stamen, then transfer it to the female parts, known as stigma, of other flowers. The benefit to the flower is that it gets pollinated and can reproduce while the benefit for the insect is that it gets the sweet food of nectar.

However, the flowers must first get the pollinator’s attention. They do this in three clever ways: through brilliant colors, compelling fragrances, and advantageous shapes.

Since most pollinators fly, the flower color must attract them. The brighter the flower, the more likely it will be visited. Flower color also attracts specific pollinators: bees are attracted to bright blue and violet colors; hummingbirds prefer red, pink, fuchsia or purple flower; and, butterflies like bright colors such as yellow, orange, pink and red.

Furthermore, insects see the flower’s nectar via an Infrared Syndrome, also known as a nectar guide or honey guide which is visible to bees but not to humans. Infrared Syndrome is a series of polarized light patterns from different color wave lengths that the bee sees: a bee’s version of GPS. Insects use these polarized light patterns as a navigating system and can hone in on nectar producing plants. What makes this a super power is that bees use polarized light to locate direction even when the sun isn’t shining. 

Scent is a signal directing pollinators to a particular flower whose nectar and/or pollen is the reward. Insect use their antennae for feeling and smelling: the fingers and nose of insects, so to speak. Flowers pollinated during the day tend to have brilliant colors and sweet scents, whereas night blooming flowers have musty, spicy, or fruity scents but softer colors to attract beetles, bats and moths. Plants emit maximum scent when they are ready for pollination; but, once pollinated their scent diminishes.

A wide variety of native plant flower shapes lure insects that have co-evolved along with the plants to ‘fit’ the flower, such as a long proboscis, or a particular body shape, or special landing requirements. The insect must be able to reach the nectar. A few examples include:

• Lipped flowers: Sage Family (Lamiaceae) or Pea family (Fabaceae) where the lip is the landing pad for bumblebees or solitary bees;
• Open bowl-shaped: Buttercup (Ranunculus spp.) attracts most insects; honeybee, bumblebee, solitary bees;
• Daisy Family (Asteraceae):
  • Compound flower heads ‘florets’ offers nectar for butterflies and mining bees,
  • Brush-like flowers (Eupatorium) attracts bees, hoverflies, and Butterflies/moths, and
  • Larger central florets (Anthemis tinctoria) offers pollen/nectar for honey bees;
• Bunched flowers: Teasel family (Dipsacaceae) attract Butterflies/moths, bees and hoverflies;
• Deep tubes: Monkshood (Aconitum), Antirrhinum (A. braun-blanquetii) attract deep throated bumblebees;
• Small tubular center Dianthus caryophyllus draw butterflies and moths, bees, and hoverflies;
• Small, flat open flowers Carrot family (Apiaceae) have flower bunches (umbels) that act as a magnet for hoverflies, small beetles, and solitary bees;
• Small bowl-shaped Geranium (Geraniaceae) with nectaries at the petal base attracts bumblebees.

Typically, exotic plants (non-native plants) are not shaped for our native pollinators and most cannot reach the pollen for one reason or another.

In addition to shapes plants have evolved customized ways of being pollinated. For instance, buzz pollination (tomatoes, peppers, Geranium) attracts bumblebee and bees because their wing vibration releases nectar; and wind pollinated flowers like Meadow Rue (Thalictrum) are usually ignored except for some bumblebees.

Pollinators of all types face innumerable threats every day including pesticides, loss of habitat, alien plant/ animal invasions, and climate change. Helping them survive and prosper requires a healthy habitat. We can help by first learning to recognize their habitats, then either enhancing or restoring their landscape, and then managing the adapted landscape long-term.

In rehabilitating pollinator habitats, start small then allow the landscape to prosper slowly yet gradually through the seasons. Offer a diverse selection of plants so pollinators will have an extended food system as well as a variety of nesting materials. Many insects need both nectar plants and larval host plants. While others, like birds, need grass for nests, bare ground for boring animals and everyone needs water. By all means, eliminate pesticides.

Meet the Pollinators  

Pollinators include bees/wasps, beetles, flies, butterflies/moths, birds, and bats. While all of these pollinators need food, shelter, and water each has specific requirements based on their lifecycle.

The majority of insects give birth by laying eggs: bees, wasps; flies; butterflies and moths have similar lifecycles called complete metamorphosis consisting of four stages: egg, larvae, pupa, and adult. Complete metamorphosis is important because butterflies lay their eggs on host plants that support the larvae through their development to the caterpillar stage. When the adult emerges from the caterpillar stage, it flies from its larval host plant to surrounding nectar plants searching for food.

Incomplete Metabolism consists of three distinct stages: egg, nymph, and adult. Insects that have an incomplete metamorphosis life cycle include true bugs, grasshoppers, cockroaches, termites, praying mantises, crickets, and lice and are consider minor pollinators if not pests.

Sustainable pollinator habitats must provide year-round food, shelter/safety, and water. This includes patches of undisturbed grass, native trees, and shrubs for bumblebee nest sites and egg-laying sites for butterflies and moths as well as birdhouses, birdbaths, and feeders for a variety of birds.

Birds need places where they can hide from predators and inclement weather. Trees, shrubs, meadows, and even rock walls provide such shelter. Native trees and shrubs of different densities and heights give birds places of retreat and safety.

Where should I begin?

Begin by surveying your available habitat areas. Identify the pollinators your want to attract then plan your gardens and/or habitats. Identify available natural materials then provide supplemental materials as needed to build a sustainable habitat. Mitigate threats as often as needed to keep your pollinators safe. Finally, identify plants then implement your plan.  

By Pat Allen, EMG