The top 6 beneficial bugs for your garden

Controlling pests in your garden or yard can be challenging. Chemical treatments to eliminate critters like grubs or aphids can be harmful to pets and children, and tend to be expensive, requiring repeat applications. Planting flowers or herbs that repel some pests can be somewhat effective, but not always reliable. However, there’s another great option for garden pest management that more and more people are beginning to recognize: beneficial bugs.

These insects and arachnids are unsung heroes of healthy lawns and gardens, controlling major pests throughout the Spring and Summer and asking only nice place to live in return. In this Gardening for Wildlife post, let’s get to know some of these tiny guardians of our gardens, how they control pests, and what we can do to invite them to our outdoor spaces. I’ll introduce you to 6 of the most common and impactful beneficial garden bugs and talk through ways to make sure they stick around your yard or garden.

Read more: Is it better not to rake your leaves?

What are beneficial bugs?

When I talk about beneficial bugs, I mean insects, arachnids (like spiders and their relatives), and other invertebrates that help reduce the populations of harmful pests that may damage lawns or garden plants, or otherwise be unpleasant to have around. Beneficial bugs are typically predators that feed on pest species, keeping their populations lower and reducing their impact. However, as you’ll see below, not all of them follow exactly that pattern.

These critters aren’t limited to one or two types of bugs, but cover a wide variety that is different all over the world. By mentioning some of the “all-stars” here and talking about their broader families rather than individual species, this introduction will give you a sense for the “good bugs” you might encounter just about anywhere in the world.

Read more: 8 insect orders every nature lover should know

How to attract beneficial bugs to your garden

Importantly, getting bonus pest control from beneficial bugs requires attracting them to your outdoor spaces. Just like attracting other kinds of wildlife from hummingbirds to bats, bringing beneficial bugs to your garden or yard requires providing resources that they need. These will include things like:

• Places to rest or shelter
• Nesting areas or surfaces for breeding
• Certain types of soil, groundcover, or habitat (for example, sunny vs. shaded areas)
• Food!

Fortunately, if you’ve got enough pests to notice them causing a problem, your yard probably has plenty of food for beneficial bugs that prey upon those pests. Because of this, the presence or absence of the right habitat is often the dominant factor determining whether or not those bugs show up and help you with your pest problem. However, there is on other thing that often has a huge impact on beneficial insects.

Read more: How to attract songbirds to your yard

Do chemical treatments and pesticides affect beneficial bugs?

One of the most common factors limiting the number and varieties of beneficial insects in peoples’ lawns and gardens is the use of pesticides and herbicides. Readers who are interested in improving their yards and gardens often ask me which pesticides they can use to reduce pests but avoid bumping the insects that they want to keep around. Unfortunately, introducing chemicals that kill “bad” insects often leads to killing off the “good” ones, too.

For example, neonicotenoids, a common class of chemicals found in many mainstream pesticides, indiscriminately kill all kinds of small arthropods. Recent studies suggest that even new pesticides that are supposed to be more target-specific can still negatively impact beneficial bugs. Although they might not kill them outright, these chemicals have what scientists call “sublethal effects” on beneficial bugs, reducing their survival or ability to reproduce. This can lead to very few, if any, beneficial bugs in a very short amount of time.

As a rule of thumb for wildlife-friendly gardening, it is best to minimize chemical use. This not only will save money in the long run, but it allows beneficial insects to get a foothold to control pests, and keeps pets and children safe from accidental exposure.

6 of the top beneficial insects that protect gardens and lawns from pests

1. Ground Beetles

Who they are: Ground beetles are a huge group of beetles belonging to the family Carabidae. As their name suggests, ground beetles spend all their time on the ground, where they run around with surprising agility searching for prey. You’ll often find them under rocks, logs, or other objects left on the ground in your yard for a long time. Ground beetles (or carabids as bug nerds call them) can be beautiful, sometimes having bright metallic colors, while most are dark with a pretty iridescent sheen. Since there are probably more than 40,000 species of ground beetles in the world, they come in a wide variety of shapes and sizes. Ground beetles often have a long head featuring prominent mouthparts (for a predator like them, this is really the business end!), and their three body segments (abdomen, thorax, and head) are clearly distinct.

What they do: These highly active predators use a keen sense of smell and sometimes strong eyesight to hunt down things like worms, caterpillars, or grubs, which they eat voraciously. Fortunately, ground beetles are largely harmless, and tend to stay out of sight. Since they are most active at night, they can do a lot of work to protect your garden while still remaining largely out of sight.

What they need: Ground beetles benefit from safe places to hide during the day, like stones, logs, or planters, as well as shelters during the Winter season. Leaving out flagstone, paving stone, or other rocks can give them good places to hunt and hide. Leaves, pine needles, straw, and other litter-based ground cover also goes a long way in supporting these beetles during cold times of year. To maintain good soil for ground beetles, you should leave certain areas of your garden untilled and undisturbed, such that they have a complex environment in which to find food and shelter from the elements.

2. Parasitoid wasps

Who they are: Parasitoid wasps include a wide variety of wasp species mostly belonging to the suborder Apocrita. This includes hundreds of thousands of different species across dozens of families. Although their name sounds intimidating, parasitoid wasps are not aggressive like yellowjackets, hornets, or some bees, and will not sting unless provoked. They often look like longer, daintier versions of these common backyard wasps. Some females have very long stingers (also known as ovipositors) which can look scary even if they aren’t dangerous.

What they do: Unlike most other beneficial bugs, parasitoid wasps don’t directly hunt prey. That is, they aren’t traditional predators like a lion stalking a gazelle or a ground beetle grabbing a worm. Instead, they control pests in a more bizarre, if somewhat sinister, way. Namely, parasitoid wasps kill pests by using them to reproduce: females use their ovipositor to place an egg inside a preferred host, and over time the larva from within that egg eats the host, eventually killing it. Different parasitoid wasps attack different hosts, but a great variety will parasitize potential garden pests like moth caterpillars, locusts, and cockroaches. Since these wasps don’t eat prey, they can parasitize a large number of pest prey at a time, being limited by how many they can find, rather than how hungry they are.

Importantly, parasitoid wasps can also perform another major garden service: they are excellent pollinators!

What they need: One of the best ways to attract parasitoid wasps to your outdoor space is to provide flowers and nectar sources to help them tank up as they search for pests to parasitize. In my experience, plants like mint, bee balm, catnip, and lavender do a great job in attracting loads of these wasps, who will hang out and patrol the surrounding area for pests that can host their eggs and larvae. Just like birds, wasps also look for water when temperatures get high, so having an accessible source of water like a birdbath can also draw them in.

Most parasitoid wasps also need a place to hide their parasitized prey and let their babies develop. Just like with birds, different species have different preferences and requirements for these nest sites. Vertical, sheltered surfaces like barn walls or eaves are great for potter wasps that build their own nests with mud. Meanwhile, moist, bare soil, sand, and gravel appeal to other parasitoids who like to dig tunnel nests to conceal their developing young.

Read more: 6 important pollinators other than bees

3. Ladybugs or Ladybird beetles

Who they are: Beetles in the family Coccinellidae are known in North America as ladybugs, and in Europe as ladybird beetles. These small beetles are often brightly colored, typically red, orange, or yellow with black spots. They have a rounded, hemispherical shape and can often be found wandering around on the surface of leaves during the day. There are thousands of species of beetles in this family found all over the world, and in most cases they are major predators of plant-feeding pests.

What they do: Ladybird beetles are specialized predators on small insects that suck plant juices, mostly aphids and scale insects. Although they are extremely small, these insects can reach great numbers, eventually drawing out so much fluid that they can reduce plant growth and survival. Furthermore, they can introduce diseases to the interior of garden plants, further endangering their survival. Both larval and adult ladybird beetles prowl plants that are plagued with aphids, and will eat dozens per day to survive. This can amount to a substantial impact on aphid populations, protecting garden plants.

These bugs have been so effective in certain garden settings, that there are small industries around importing them for pest control.

IMPORTANT: Introducing new species to any environment carries a risk of spreading invasive species, Which can do a lot of harm to local ecosystems. Instead, it is much better to try and attract your own ladybugs rather than purchasing them from somewhere else.

What they need: Just like with ground beetles, ladybugs need a nice place to spend the Winter. If you have safe places for them to cozy up during the colder months, you’ll likely see more in the Spring and Summer. Unlike the ground beetles, ladybugs typically like elevated, dry, tight spaces for overwintering. Instead of sheltering on the ground, they move into holes in trees and similar natural cavities during Winter. Ladybugs also frequently enter houses, sheds, and garages to sleep off the Winter, making them one of the most common household insects.

Plants with large, spacious and nectar-heavy flowers are also a great way to support ladybugs. When not chowing down on aphids, they visit flowers to sip nectar or even snack on small amounts of pollen. Daisies, milkweed, Queen-Anne’s-lace, and yarrow, and fennel make great food plants for these gorgeous beetles to supplement their diets. These sizable flowers are easy for clumsy-flying beetles like ladybugs to make a landing and get the extra nutrition that they need.

Read more: Why are there suddenly so many bugs in my house?

Wolf spiders

Who they are: Wolf spiders belong to the family Lycosidae. They act much like ground beetles, using their sharp eyesight to find and attack prey on foot. These are typically brown spiders with thicker legs that, rather than hanging out in a web, scurry around along the ground. Wolf spiders exhibit wandering behavior, moving widely in search of mates and prey. As a result, many species have large home ranges, moving between different habitats.

What they do: Just like ground beetles, wolf spiders are fearsome—and hungry!—predators that grab pests that live on the ground. This means things like crickets and grasshoppers, cockroaches, and large ants are on the menu. As a result, many savvy gardeners recognize these spiders as excellent pest control for protecting ornamental and food plants.

What they need: As mainly nocturnal predators, wolf spiders need shelter to hide out during the day. Providing shady micro-refuges in your yard, like small woodpiles, rockpiles, or areas with a thick groundcover or low shrubs can help them feel at home.

Lacewings

Who they are: Lacewings include several families in the little-known insect order Neuroptera. Green (Chrysopidae) and brown lacewings (Hemerobiidae) are some of the all-star beneficial insects in this larger group. Aside from differences in color (and, as entomologists will tell you, some differences in their wing veins), these two groups of bugs look similar. They have long, clear wings striped with netlike “wing veins”, slender, streamlined bodies, and small heads. Lacewings can be really easy to tell apart from other insects in flight: they are slow, somewhat clumsy fliers, with a drifting flight pattern.

Larval lacewings, which are also highly beneficial insects, look much less graceful. These little monsters often have a flexible, slender body with thin legs and a broad, flat head equipped with sharp, intimidating mouthparts. Their body is often covered in transparent hairs that can look spiky. These tiny larvae also have a tendency to camouflage themselves by covering their bodies with bits of dust or plant matter. After accumulating camouflage for a couple of days, they start to look like a walking dust-bunny.

What they do: Like ladybugs, both of these families of lacewings include voracious aphid hunters. Since aphids can multiply to huge numbers and weaken or kill plants by drinking their fluids or introducing pathogens, lacewings’ appetite for aphids can go a long way. Both adult and larval lacewings feed on these aphids, making them widely recognized as valuable pest control agents.

You’ll find lacewing larvae marching up and down plant stems and along leaves in search of aphids and other plant “blood-suckers”. Often wearing a thick camouflage of fluffy dust and detritus, they march up to whole groups of aphids and pierce them with their sharp mouthparts. Once they have bitten an aphid or scale insect, the young lacewing can drink its bodily fluids through its mouthparts. Meanwhile, its dustbunny camouflage not only keeps it well hidden, but can prevent ants that may be guarding the aphids.

What they need: Like many other insect predators, lacewings do well with complementary food sources, like pollen- or nectar-rich flowers and sources of water. While lots of other blogs will recommend specific plant species to attract beneficial insects like lacewings, these aren’t generalizable to different parts of the world. In fact, introducing species of plants from elsewhere can do more harm than good. Instead, I recommend going for a variety of native wildflowers; in my experience, meadow wildflowers, planted in sunny parts of the yard or garden, do the best at attracting lacewings.

(Some) Ants

Who they are: As the most numerous animal on Earth, ants need very little introduction. You’ll find ants just about everywhere, and with tens of thousands of species, there are plenty of different kinds. Ants are truly the dominant predator among insects wherever they live, so much so that many insect species develop special defenses to repel them. Importantly for your garden, the great variety of ant species means that they can have many different impacts in outdoor settings. Many species are omnivorous, meaning that they consume a variety of foods, including seeds and dead animal matter, in addition to hunting. However, some ant species are bigtime carnivores, eating other insects and invertebrates including grubs, worms, slugs, leafhoppers, and other potential pests.

Some ants can be pests, consuming garden plants, undermining root systems, or providing a nasty surprise if you step on their nest barefoot. Invasive ant species, like fire ants (Solenopsis invicta) in North America, can be an especially harmful presence in your garden. On the other hand, some native ant species can not only help deal with pests, but also control or push out ants that might be less pleasant to have around. That’s why its particularly important to identify what kind of ants live in your garden. You can check out my guide to identifying insects below, or leverage an outdoor app or field guide for species identification.

Read more: An 8-step guide on how to identify bugs in your house or yard

What they do: Predatory and omnivorous ants rove widely over the ground, on vegetation, under large objects, and in the leaf litter for whatever kind of prey they can find. They are one of the few groups of beneficial bug predators that can patrol just about all habitat types in your yard. Since there are a great many mouths to feed, ants can really put a dent in pest populations. Rather than targeting specific prey species, they tend to be an over-arching predatory pressure on insect populations in the yard or garden, preventing any one species from becoming hyper-abundant. This is especially important for pests, which generally become a bigger problem when their numbers get out of control.

Importantly, many ant species are omnivorous, so they could also feed on other beneficial insects. Having a wide variety of habitat types and plant species in your garden can go a long way in helping other helpful predators avoid risk of falling prey themselves.

What they need: Ant species typically need space to build their nests, which for many are dug into the soil, where networks of tunnels support growing colonies. Soil types (for example, loamy, mulchy, sandy, clay) can have a big impact on what and species move into a place. Likewise, other habitat elements like paving stones, cement patios, trees, and open areas can provide micro-habitats for ant colonies. These features can also create differences in ground temperature throughout the year, which also affects which ants can live in a space.

Is it a good idea to purchase beneficial insects?

As appreciation and awareness of the value of beneficial bugs for pest control has grown, an industry has formed around getting people the insects they want in their yards and gardens. It’s very easy to pay online and get live insects, their eggs, or larvae shipped to you and then release them into your yard. After all, isn’t that a much easier and faster solution than trying to attract insects in your area? Should you purchase ladybugs? What about lacewings?

While buying beneficial insects is certainly a simple and straightforward way to increase populations of pest predators in your outdoor spaces, it can be problematic. Most importantly, industrial insect providers are spreading a single species or single variety of beneficial insects to wherever their customers order from. As a result, in larger countries, new insect species can be widely introduced, simplifying the local environment. Many of these introduced, commercially available species will not integrate as well in the local ecosystem, which could mean that (1) they die out quickly and can’t do their job, (2) that they need to be repeatedly replenished with more purchases, or (3) that they do environmental harm, impacting native species both inside and outside of a garden or backyard. This can negatively impact local biodiversity and ultimately compromise the value of an area to wildlife.

Read more: What is biodiversity?

Are praying mantises good pest control?

Praying mantises are some of the most popular commercially available insect predators on the market. Not only are they tireless and efficient predators, but many species on the market can grow quite large and are fun to watch. I bet you noticed, though, that mantids didn’t make it into my list of top beneficial insects. Here’s why:

The majority of imported mantids in North America are the Chinese mantis (Tenodera sinensis), a very large-bodied species that can reproduce rapidly, and which eats lots of non-pest insects. In fact, in my own observations of Chinese mantids in the wild, they tend to do more damage to pollinators like bees and butterflies, and even have a go at hummingbirds (luckily with little success!).

A naturalist mentor of mine once compared the introduction of large mantid species to “unleashing tigers in the suburbs”. There just aren’t many, and in many cases any insect predators of their size and ferocity in much of North America, so they have the potential to do substantial ecological harm. Their large size makes them ineffective at taking out small-bodied insects, which include many of the most important insect pests. Furthermore, they outcompete native mantis species in places where those are found, and do even greater damage in ecosystems which don’t have mantids. Because of these characteristics, many experts consider imported mantids invasive species.

Read more: Why are invasive species a problem?

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