Insects: Friends or Foes? The Many Roles of Beneficial Insects

Angela Cruise
Product Developer

February 2017

Without insects, the world would be an entirely different place—and not in a good way as you might think! When it comes to insects, we often focus more on the bad than the good. Insects help us a lot more than you may realize. In terms of public opinion, insects exemplify the proverb “one bad apple spoils the bunch.”

Currently, scientists have identified nearly 1 million species of insects, but some estimate that there are between 1 to 30 million more species yet to be identified. Of this vast number, fewer than 1,000 are actually insect pests capable of transmitting disease, harming crops, or damaging structures. This means that over 99% of all insects on Earth are not pests! Most insects in the world are considered either neutral or beneficial as they relate to humans. Neutral insects are critical components of ecosystems but do not cause any direct benefit or harm to humans. Beneficial insects, however, have great value to humans for a number of reasons.

Essential Pollinators

Over 90 commercially-produced crops in the United States—including apples, squash, and blueberries—depend on the honeybee (Apis mellifera) for pollination. It is a common misconception, however, that the honeybee is the only important bee for pollination. In fact, some crops, such as tomatoes, rely more heavily on other species of bees for pollination. In the United States alone, there are over 3,000 species of bees.

Bees are not the only pollinators in the world; many plants depend on other insects for successful breeding. Many types of flies, including fruit flies, hover flies, bee flies, and even blow flies, are significant pollinators. Butterflies and moths are also known to pollinate some plants, as do beetles, thrips, wasps, and ants. In fact, some of these insects, such as the fig wasp, are specialized for pollinating certain varieties of plants.

Fly covered in pollen

Valuable Producers

Beneficial insects are responsible for many products humans use and consume every day. Honey, beeswax, and bee pollen (a nutritional supplement) are common products from honeybees. Honey alone is responsible for millions of dollars in revenue for beekeepers around the world every year. Bees also make propolis, a sticky substance found in some chewing gums, car waxes, and traditional medicine. Silk, another insect product, is produced by the silk moth, Bombyx mori. This insect has been selectively bred and used in textile production for so long that it has become dependent on humans for its survival. The production of silk has had an enormous impact on the history of Chinese trade and economy.

Some lesser known insect products include dyes and shellac. Both dyes and shellac are produced by tiny scale insects. These products are common ingredients found in foods and makeup. Many red tinted makeup products, like lipstick and blush, as well as foods like jellies, juices, and bottled marinades, contain carmine dye from cochineal scales. Shellac is often used as a coating on pills, candies, and even citrus fruits. Odds are that you probably eat or wear something containing an insect-produced product every day!

A Culinary Delight

In roughly 80% of the countries in the world, individuals consume another insect product—the insect itself! The practice of eating insects, or entomophagy, is common almost everywhere except in Western culture. Many insects are high in protein and efficiently mass-reared, so the process of entomophagy is starting to become more popular in the West as a means of combatting the high costs and environmental implications of some of the practices involved in traditional meat production.

Various products produced by bees

Medical Treatment and Therapy

In addition to their roles as pollinators and producers, honey bees may also be healers. Bee venom acupuncture (BVA) is a therapy used for those suffering from rheumatoid arthritis and osteoarthritis. In BVA, a patient is repeatedly stung in the arthritic area, as it is believed that bee venom may ease the pain of arthritis through its anti-inflammatory properties. The process is controversial, but many arthritis sufferers swear by its benefits.

Maggot therapy is a promising medical practice for chronic ulcers and other wounds that have difficulty healing. In this therapy, disinfected blow fly maggots are applied to a wound. The maggots will only eat dead, or necrotic, tissue from the wound, leaving behind healthy tissue. As they feed, the maggots release antimicrobial secretions that keep the wound free of harmful bacteria. Maggot therapy greatly enhances wound healing, leaving patients with minimized scarring and faster healing times.

Efficient Decomposers

Decomposers help break down dead plant and animal matter. The role of insects as decomposers cannot be underestimated. Without decomposers, organic matter would pile up and its beneficial nutrients would remain unused. Termites are important decomposers of wood. If you find a downed tree in the woods, peel back its bark and you will likely reveal termites. These insects feed on the dead wood and create rich soil in the process. Termites are a prime example of how an insect can be considered both beneficial and a pest. When wood recycling occurs in the forest, it is beneficial. When it occurs in your house, it is most definitely a pest situation!

Many flies and beetles are specialized for decomposing dead animal matter. These insects feed on the decomposing animal, eliminating the tissue and enriching the soil below. These insects work together in this mini ecosystem to efficiently consume the resource and use its nutrients for their own reproduction and growth. 

Biological Control

Many insects are natural enemies of crop-damaging pests. These beneficial enemies may take the form of predators or parasitoids. A common beneficial predator is the ladybug. Ladybugs eat aphids, soft-bodied insects that can damage a wide variety of plants of both economic and aesthetic importance. Many serious gardeners cultivate plants that provide safe refuges for ladybugs. Some even purchase additional ladybugs from retailers as a natural control method. Cultivating beneficial insects can help reduce reliance on insecticides for pestiferous insect control.

Parasitoids are insects whose larvae parasitize a specific host species. For example, some specialized species of tiny braconid wasps use their egg laying structures, or ovipositors, to pierce a tomato or tobacco hornworm and lay eggs. When the eggs hatch, the developing larvae feed within the hornworm, eating it from the inside out. This feeding does not immediately kill the hornworm. When finished feeding, the wasp larvae will emerge from the inside of the hornworm’s body and pupate. Adult wasps will soon emerge, and the hornworm will die. Thus, these wasps help to biologically control a pest species.

Parasitized hornworm covered in wasp pupae

Summary

Humans benefit from the behaviors and products produced by many beneficial insect species. Unfortunately, these beneficial insects are often overshadowed in public opinion by the proportionally small number of insect pest species. Certain kinds of food, clothing, health care, and even the landscape of the Earth are all heavily influenced by beneficial insects. It would be difficult to go even a day without eating a food pollinated by or containing a dye produced by insects. Where do you see insects benefitting you in your everyday life? How would life be different without beneficial insects?