View Our Woods
See Us On:
« Dr. Robert Wagner Invites a Public Feedback on the Spruce Budworm Report | Main | Marvelous Maple: Maple Syrup 101 »

Beneficial Insects in Maine Forests

Insects described as beneficial are those that prey on bugs humans would classify as destructive or undesirable. Carpenter ants, fleas, and termites all fit into that category. Ninety-seven percent of all arthropods found in or around your home are either neutral or beneficial. Homeowners can use beneficial arthropods to keep their yards free from pests and the pesticides that would be necessary to kill an outbreak.

There are two different kinds of helpful arthropods: parasitoids and predators. Predators assault their prey, often by setting traps or overpowering the victim. Predators include spiders, most beetles, and some species of wasp.

Parasitoids on the other hand will attached to a host and reproduce by laying eggs on or in the host organism. When the eggs hatch, the larvae often eat the host. Sometimes the eggs hatching will be enough to kill the host before being devoured.


Here are five of the most helpful arthropods.


  1. Ground beetles are large oval bugs with a sleek exoskeleton, long legs, and strong, sharp jaws. Beetle larvae is also predatory, feeding on caterpillars and small insects. Adult beetles also consume snails, slugs and moths.
  2. Spiders are predators and have a wide variety of methods for catching prey. Some build trapdoors, striking when an insect walks by. Some use webs, others their impressive speed, strength, and reflexes. Poisonous spiders found in North America are not typically present in Maine. Spiders are the most common type of predator.
  3. Syrphid flies have a yellow abdomen and are mistaken as yellow jackets and honey bees. These insects are valuable backyard allies. They don't sting or bite, eat aphids and other pests, and contribute to the cycle of nectar and pollen.
  4. Tachinid flies are a parasitoid that lay eggs on their host. When maggots hatch, they enter and devour the host. These bugs hunt caterpillars, grasshoppers, and Japanese beetles, just to name a few.
  5. Wasps are known for being aggressive predators, but there are species of parasitic wasps, too. Wasps bite and sting their prey and for this reason are more likely to target "soft" prey like caterpillars or snails. Wasps can be dangerous too close to your home. Always consider the safety of your family and pets, first.


If you want to attract some assistance fighting pests there are some easy ways to spruce up your yard.

  • Most arthropods exhibit a preference for certain types of plants. Flowers with both pollen and nectar tend to attract beneficial parasitoids and predators alike.
  • Different flowers mature at different times throughout the year. Plan your yard so you have flowers blooming at different times. The more often nectar and pollen are available for the surrounding environment the better.
  • The University of Delaware investigated zapper lights. They determined that these types of lights killed far fewer pests than beneficial insects.
  • Be prepared to see some damage to your vegetable garden. Most beneficial arthropods will not cause enough harm to compromise the plant.
  • It never hurts to use a little extra water or shade. Keeping the yard fresh and growing will improve the overall health of the land's ecosystem. If you have the space, planting a few trees will help, too.