Pro-Pollinator: Benefits of Pollinator Insects

This is the first of a series of articles by Climate Action Coffee that seeks to engage readers to understand the importance of native plants and pollinator insects. Today we focus on pollinator insects whose numbers are shrinking due to loss of habitat.

Benefits of Pollinator Insects

Sure, carpenter ants and termites will eat your foundation and many mosquito species spread disease, but all insects are not bad actors, and even the bad ones have a positive side. We humans and other species have co-evolved with insects and cannot live without their contribution to the food web. Birds need soft larvae/caterpillars to feed their young, and many count insects as a major part of their diet. Insects are also an important food source for fish, snakes, frogs, turtles, bats, and hummingbirds.

Insects such as crickets and grasshoppers form an important part of the diet in many human cultures. For centuries, we have harvested cochineal insects and crushed them to make the natural red dye carmine to color food, cosmetics and textiles. Pollinator insects spread seeds and pollinate flowers and plants, one third of which produce food we eat.

While many readers may not remember insects gathering on screen doors at night attracted by the light, or splattering on their windshields, I do. Sadly, the disappearance of something so common such a short time ago provides empirical evidence that insect populations are declining. There has been a 40% reduction in the global insect population over several decades. Insects are losing their habitats owing to construction, pollution, the effects of climate change, use of pesticides, and more. The decline in the insect population has contributed to the reduction of the global bird population by a staggering 50% over the last 50 years.

Here is a little information about a few important pollinator insects that live in our backyards, which may make you reconsider how you think about insects:

Mosquitoes:

One insect, the mosquito, of which there are 3,500 species, gets an especially bad rap, deservedly so. We associate them not only with itching, but with the Zika, West Nile, chikungya viruses, as well as malaria and yellow fever. In Maryland, 3 species carry disease: Aedes albopictus and Aedes aegypti carry the Zika, dengue and Chikungya viruses, and both breed in temporary pools of water such as flower pots, and underneath English Ivy leaves. Culex pipiens carry West Nile virus and breed in stagnant pools of water. Flower nectar is the most common food for mosquitoes, but females will pursue a blood meal when laying eggs.

As much as some mosquito species are vectors for spreading disease, mosquitos also are key to the survival of other species of plants and animals. They pollinate certain orchids, and both the winged adults and aquatic larvae are part of the food web for dragonflies, turtles, snakes, deer, caribou, elk, hundreds of fish species, bats and hummingbirds. Mosquitoes are an important food source for many birds. In their larval stage, mosquitoes clean and filter dead organic matter and microbes from the water, creating nitrogen that is essential for plants.

Dragonflies:

Besides adding beauty to your yard with their long bodies and transparent wings, dragonflies consume hundreds of mosquitoes a day. They are also drawn to flies, termites and ants. In their larval stage, dragonflies are aquatic and eat tadpoles, mosquitoes, fish, other insect larvae–and even each other. They are known for their acrobatic flying skills and can fly straight up or down, hover like a helicopter and even mate in mid-air. These skills allow them to catch their prey in the air with their feet and since nearly all of its head is an eye, their incredible vision makes them a very efficient predator.

Bees:

Thousands of species of bees exist throughout the world. Some 400 species are native to Maryland with the most common being: the common eastern bumble bee; the larger carpenter bee; the colorful green shiny sweat bee; the plasterer bee; the leaf-cutter bee; and the miner bee, which emerges in early spring to pollinate azaleas, and apples. Most bee species do not live in hives but are solitary and build their nests in the ground, in pithy stems, or wood. Having a variety of bees in your yard enhances pollination throughout the summer months. Planting native plants helps support the native bee population by allowing bees to nest in the ground, wood, stalks and stems–and procreate so their young live on to pollinate in future years.

Butterflies:

Butterflies skip from plant to plant carrying pollen on their bodies from plant to plant. They live on a liquid diet, aka nectar, using their feet to taste their meal. They may stand on the side of a puddle to drink water. At night they roost, or rest. There are four stages in the life cycle of the butterfly and moth. Each lays a tiny egg on a plant which, in about 4 days, hatches into a caterpillar or larva. The larva or caterpillar’s job is to eat. A caterpillar may shed its skin 4-5 times until it grows 100 times its original size, up to about 2 inches in length. When fully grown, the caterpillar becomes a pupa whose cells specialize and divide until an adult butterfly forms. It can stay in the pupa stage for weeks, months or longer. When fully developed, the butterfly emerges from its cocoon, spreads its wings and flies off to pollinate and propagate.

Moths:

While butterflies pollinate during the day, most, but not all, moths perform this duty after dark. Their prime purpose is to pollinate and procreate, living for a matter of days without even eating. In fact, some do not even have mouths. They are excellent at camouflaging themselves and blend in with leaves or tree bark. They exist in many colors and sizes and there are many more of them than butterflies.

Fireflies:

A little known fact about fireflies is that they are actually beetles and belong in the family of glowworms. They love moisture and live in humid regions of Asia and the Americas. Each has a dedicated light organ located under its abdomen. To create light, the firefly takes in oxygen and, inside these special cells, combines it with luciferin to produce an intermittent light that flashes in a pattern specific to their species. Their light also acts as a defense mechanism which alerts a predator of their unappetizing taste. Female fireflies lay their eggs in the ground where their larvae will develop into adulthood. The larvae feed on worms and slugs in the soil but adults prefer nectar or pollen. The purpose of this delightful insect is to pollinate at night, procreate–and entertain us on summer evenings.

How do we support our insect populations?

If we want a healthy and biodiverse native pollinator population, as well as healthy soil, we need to protect insects. We must stop indiscriminately killing insects and poisoning our soil with pesticides that destroy their habitat. Larval and adult insects need adequate food sources, which we can foster by populating our gardens with native plant and tree species, which provide adult insects with flower nectar and leaves for their larvae to eat. Refrain from raking in the fall so the leaves and stems in your garden can maintain a winter habitat for insects, saving clean up for the spring after the weather is consistently warmer (50 degrees F for two straight weeks).

Look for next month’s article as we share with you more interesting and useful information about our least favorite insect, the mosquito. In the meantime, I bring you a poem by Mary Oliver.

BACKYARD

Mary Oliver

I had no time to haul out all

the dead stuff so it hung, limp

or dry, wherever the wind swung it

over or down or across. All summer

it stayed that way, untrimmed, and

thickened. The paths grew

damp and uncomfortable and mossy until

nobody could get through but a mouse or a

shadow. Blackberries, ferns, leaves, litter

totally without direction management