Why Insects & Caterpillars Must Thrive. You Can Help.

Written By Noble Root

Aside from a few “nuisances,” the vast majority of insects and bugs are absolutely harmless to humans. Not only that, they’re actually critical to our survival.

In this article:

  • Why insects are key to our survival

  • Caterpillars, a keystone species

  • The Great Insect Die-Off

  • How birds fit into the picture

  • What you can do

  • Resources

“If all mankind were to disappear, the world would regenerate back to the rich state of equilibrium that existed ten thousand years ago. If insects were to vanish, the environment would collapse into chaos.”

-E. O. Wilson

Did you know that insects serve as the base of the food chain and are critical to our survival? While we can probably all agree that mosquito bites and house flies aren’t great, the vast majority of insects and bugs are absolutely harmless to humans and are actual vital to our survival.

Many people are surprised to learn that flies are critical pollinators too! “In fact, a recent analysis of crop species found that flies visited 72% of the 105 crops studied (bees visited 93%),” according to Penn State Extension. “In some cases, flies can provide more consistent pollination in early spring than bees, likely because they are often active at cooler temperatures.” (Source)

What’s in a name? 

  • “Arthropod” encompasses the largest phylum in the animal kingdom, with 84% of all known species of animals. This includes insects, spiders, centipedes, millipedes, and even lobsters and crabs. 

  • “Insect” is a scientific term that includes bees, flies, and butterflies. All insects have 6 legs and 3 body parts: the head, thorax, and abdomen. Most insects have wings.

  • “Bug” is a broader, more colloquial term that refers to anything insect-like that creeps, crawls, and/or flies but might not have exactly 3 body parts and 6 legs. 

  • “True bugs” are a specific type of arthropod that include stink bugs, bed bugs, and cicadas. 

  • Meanwhile, “bugs” like ladybugs and June bugs (with “bug” in their name!) aren’t true bugs at all, but rather beetles.

  • “Beneficial Bugs” are major helpers in the garden and include pollinators, predators, and parasitoids. Attracting all three types of beneficial bugs helps ensure balance in the ecosystem. Pollinators include bees, butterflies, flies and moths. Predators eat other garden pests and include ladybugs, green lacewings, praying mantids, and predatory wasps. And parasitoids which are predominantly wasps, bees, and flies lay eggs on or in other pesky bugs. When the larvae hatch, the young insects feed on the host and kill it.

What would humans do without insects? 

Everything alive relies on insects for survival. From the plants they pollinate to the countless birds and animals that rely on the plants just pollinated, insects form the critical base of the food web.  

In Nature’s Best Hope, Douglas Tallamy describes how insects pollinate 87.5% of all plants and 90% of the world’s flowering plants. Without insects, pollination would be nearly impossible, and consequently we’d lose a massive supply of food and biodiversity. 

We’d also lose an important source of pest control for crops. For example, without predator insects that eat other insects, pests like aphids, mites and mealybugs could quickly get out of control and decimate gardens of fruits, vegetables, and ornamental plants like roses.  

Did you know: Aphids are parthenogenetic, which means they can reproduce without mating. They don’t even have to waste time waiting for eggs to hatch – aphids give birth to live young.

And that’s not all, the loss of insects would affect people’s pocketbooks: 

Without insects, we’d lose rich cultural sites like the Monarch Butterfly Biosphere Reserve in Michoacán, Mexico, where millions of monarchs overwinter every year. This UNESCO World Heritage Site hosted more than 160,000 people in 2021, helping the local economy thrive during the winter months. 

Closer to home, what would Vaux’s Swifts eat if not for the flying bugs at Chapman Elementary in NW Portland, Oregon? Without dragonflies, flies, ants, aphids, wasps, and aerial spiders, there’d be no neighborhood gathering, no show, and no more delighting in this annual tradition with family and friends. 

If all that isn’t enough to show why insects rule our world, picture this scenario. Insects help break down plant material and other dead organisms, allowing nutrients to be reused and absorbed by other plants and animals. It’s a grim picture, but the world would be filled with rotten, stinky carrion without the flies’ and beetles’ ability to thoroughly clean up nature’s messes. 

Caterpillars are a keystone species

Although they might look like worms to some, caterpillars are in fact insects. Contrary to popular belief, birds eat few other insects or earthworms, preferring caterpillars with their relatively large, juicy, and nutritious bodies. 

Caterpillars are easy prey for birds as they’re typically exposed while crawling on plants. They’re also perfect for birds feeding their young, especially when considering they are 200 times larger than an aphid, more accessible to digest than a hard-backed beetle, and jam-packed with fats and nutrients necessary for adult birds to reproduce and chicks to grow. 

How many caterpillars does a bird eat each day? Some scientists estimate that adult birds feed their brood anywhere from 300 to 800+ caterpillars a day! This adds up to thousands of caterpillars needed to feed to chicks over the course of about 2 weeks, while adult birds actively feed their young. 

The Great Insect Die-Off

Over the past several decades, 41% of insect species have reached a state of rapid decline, with a third of all insects at risk of extinction. In Europe, flying insects have declined 80% on average. These sobering statistics come from a review of more than 70 data sets, some dating back over 100 years. 

One of the biggest problems with the great insect die-off is the subsequent loss of birds that rely on insects for food. Some experts estimate that bird populations have dropped by more than 400 million in the past 30 years. Given that birds aren’t able to reproduce or feed their young enough without caterpillars, this shouldn’t come as a surprise. 

The three primary reasons for these massive insect extinctions are human-caused:

  • Habitat loss

  • Pesticide use

  • Climate change 

If we can accept that human activities are to blame for the global reduction of birds and insects, the good news is we’re also the solution. Because insects are so small, and they take so little space to survive, even small changes in our own homes and backyards can make a huge impact for insects. 

With nearly 40% of Oregon’s 63 million acres privately owned, individual landowners and homeowners have an extraordinary opportunity to help bring back the insects and the birds from their devastating decline. Caterpillars are the true heroes of the insect world, and their future depends on us. So what can we do to help?

If you do nothing else, plant an Oregon White oak tree (Quercus garryana). 

It might seem ridiculous, but this ONE action might just have the largest impact increasing caterpillars as a food source for every other living thing in your area. They also sequester tons of carbon in their roots and wood, and can live for hundreds of years. Consider this:

  • Oaks can support at least 934 different species of caterpillars nationwide – the most BY FAR of any other plant. In comparison, hemlocks support 92 species and sycamores support just 45. 

  • The leaf litter underneath the tree provides terrific habitat for hundreds of insects, arthropods, and invertebrates.

  • Oaks are very slow growing, so by planting a tree today you are actually planting a tree that will benefit the generations to come!

Keep in mind, what lies under the oak tree matters greatly. One tree can house thousands of caterpillars as they transition from one stage to the next in their metamorphosis. Unfortunately, if the caterpillars drop down into a turf-grass lawn and have to crawl for days to find food or safety while evading the lawnmower, they aren’t likely to survive.

To help ensure caterpillars’ survival, keep grass at least 6 feet away from the base of the tree and apply leaf mulch instead. Simply changing what’s under that beautiful white oak tree could save millions of caterpillars over the lifetime of the tree. 

What will happen without caterpillars?

Without adequate caterpillar habitat, we won’t have any more caterpillars. And fewer caterpillars mean birds will continue to suffer, especially as they reproduce and raise their young. Without birds, we’d lose their pollination and seed dispersal skills, as well as their natural pest controlling ways. Not to mention, we’d lose the simple beauty and wonder that comes from watching birds and butterflies in our yards and natural environments.

In short, we’d be in trouble without insects and especially without caterpillars. As environmental journalist Oliver Milman said, without insects “we would be without many of the staples of our lives.” He explains how we wouldn’t even have ice cream anymore because cows eat alfalfa, which is pollinated by insects. Curries would be out, too, as cardamom, cumin, and other spices – the very things that make our dishes colorful and interesting – would cease to exist without insects. 

What you can do

Here are five things you can do today to make your yard more climate adaptive and friendly to insects:

  1.  Plant an oak tree if you have the space and set future generations up for success. Get one as large as you can because they grow very slowly. Oak trees are the absolute best things to plant because they can host HUNDREDS of caterpillars, more than any other type of tree. 

  2. Remove all or a portion of your lawn and replace it with native plants. Utilize this fantastic resource from Audubon and learn which plants are best for caterpillars in your own backyard here. 

  3. Turn off outdoor lights at night or install motion sensors to avoid attracting insects like moths. These insects can get confused, worn out, and die from exhaustion with outdoor lights on. 

  4. Do not apply pesticides or fertilizers. Instead, design your yard space as an intentional, native, habitat for caterpillars, insects, and butterflies. 

  5. Schedule a consult for help in choosing the plants to create habitat for insects and caterpillars. Not all plants are equal! Asking a professional can be extremely helpful if you know you want to make a change but don’t know where to start.

    Resources:

     

    About:

    Nicole Spencer is the founder and Principal Garden Consultant for Noble Root. She is a Gardenary-certified Garden Consultant, Kitchen Garden Coach, and Licensed Landscape Contractor specializing in raised bed edible gardens and backyard habitats. Her passion is helping clients transform their backyards into healthy, thriving, and productive oases that benefit people and pollinators in Portland-metro and Vancouver, Washington areas.

Growing flowers in the Apiaceae Family will attract a variety of “Beneficial Bugs” to your garden to help with pest management.

Noble Root https://www.nobleroot.com
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