Garden protectors and a bit of fun terror: the native mantids, assassin bugs, and lady beetles

Gardening is not just about nurturing plants and flowers, but it's also about creating a harmonious and diverse ecosystem. My garden is living proof that nature can be functional and beautiful while at the same time, delicate, voracious, and fascinating as heck. In this blog post, I’d love to draw your attention to a few of my favorite insect predators; important creatures that can help keep our gardens, and subsequently, our world, healthy and thriving.

A native praying mantis (Stagmomantis carolina) and a tiny lone purple coneflower in the background. This female mantis may be the great-great-grandmother of my 2022 mantis population, she was witnessed laying eggs on a tree shortly after this picture was taken.

First on our list is the Carolina mantid, also known as the praying mantis and referred to as the native mantis from here on out. These fascinating insects are known for their unique appearance, with their long slender bodies and large front legs that are held in a prayer-like position. Native mantises are excellent hunters and feed on a variety of pests, including aphids, mites, caterpillars and my green bean-munching nemesis, the Japanese beetle. They can be found throughout much of North America, south into Brazil, and are a welcome addition to any garden, helping to keep unwanted pests in check. Check out my video about native and non-native praying mantises here!

A juvenile Carolina mantis stands on my back porch chair, shortly after hatching. Praying mantises hatch fully developed - this one zoomed off within minutes.

Next up are the Assassin Bugs, also known as wheel bugs. These insects are known for their distinctive cog-like wheel on their backs, which is used to intimidate potential predators (and gave gave me BIG EYES when I spotted my first one). They feed on a wide variety of pests, including stink bugs, caterpillars, and aphids. Assassin bugs are effective hunters, and their presence in the garden can help reduce the need for chemical pesticides. I once read that Dr. Michael Raupp, an entomologist at the University of Maryland, referred to them as the “lions of the food web” for our garden and, always a sucker for a quippy line, I’ve never forgotten it. The first assassin bug appeared in my garden at the top of my green bean trellis, happily snapping up the Japanese beetles harboring there, and a touchstone of every summer since has been finding my first wheel bug of the year. My husband, who is not nearly the garden-nut that I am, also likes to try and spot them.

A wheel bug on top of a green bean trellis.

The third insect I’d like to spotlight is the lady beetle, also known as the ladybug. These cute and colorful insects are an essential part of any garden ecosystem, in addition to being the first “bug” nearly every little kid notices and subsequently draws (or maybe, that was just me). Omnivorous ladybugs feed constantly on aphids, mites, and other small insects, as well as nectar, pollen, and even mildew if they’ve effectively vacuumed up all the aphids on the plant. My region tends to have just as many non-native ladybugs as native, so a quick trick to mostly distinguish them is “nine spots are native.” And, you know those really smelly look-alikes that congregate around your house in the fall? Not native. Grrrr.

A ladybug resting on the fading blooms of a native wild senna plant. The aphid population that had collected on the stems here was gone within three days. You can also see the seed pods of wild senna forming, which is a really nice fall/winter interest feature of this plant.

When good predator insects eat…the good insects

It’s inevitable. One of these predators may at one point catch an insect we wish they hadn’t caught. The loss of a member of any species, especially one as popular and beloved as the monarch butterfly, can be a difficult and emotional issue. However, it's important to remember that nature is a complex and interconnected system, and the loss of one member can sometimes be necessary for the survival and health of others.

In the case of predator insects, such as ladybugs and mantids that I’ve talked about here, they play a crucial role in controlling the populations of pests that can damage plants and flowers. Without these predators, the pest populations can grow unchecked, causing widespread damage to the garden and outnumbering native insects. This can have a cascading effect on the entire ecosystem, disrupting the ideal proportions of predators and prey.

An ambush bug is pictured here, waiting on the petals of a purple coneflower. While not covered in this post, they are another sign of a good ecosystem!

It's also important to note that not all predators are a threat to threatened species. For example, the monarch butterfly has many natural predators, including birds, spiders, and other insects, and the loss of a small number of butterflies to predator insects is unlikely to have a significant impact on their overall population.

Moreover, there are many steps that can be taken to minimize the impact of predator insects on threatened species, such as planting a diversity of plants to provide a range of food sources for both predator and prey insects, and no surprises here - avoiding the use of chemical pesticides that can harm both predator and prey insects.

While the loss of any beloved insect, including a monarch butterfly, is unfortunate, it's important to understand that it can be necessary for the overall health and balance of the ecosystem. By taking a holistic approach to gardening, we can help to minimize the impact of predator insects on threatened species and contribute to a thriving and diverse ecosystem.

Buying Insects

I owe you an entire SEPARATE blog post about never buying insects for your yards as pest control. My quick plea for now is to never buy any insects. Ever. Of any kind. It will take more time than two day shipping, but don’t use pesticides, leave stems and leaves over winter where you can, plant native, and just wait impatiently for the good insects to arrive on their own. In my own suburban garden, three years is about what it took for the first praying mantises to show up, and another two years after that my lions, the assassin bugs, appeared. 

Let’s recap! The native praying mantis, assassin bugs, and lady beetles are a helpful and fascinating addition to any garden. Not only do they help keep pests in check, but they also add a touch of beauty, wonder, and a bit of fun terror(?) to your outdoor space. Just kidding. They are worth it. So, the next time you're out in nature or a truly bad-arse garden, take a moment to scope out and appreciate these garden protectors.

See? A bit of fun terror! This is a juvenile assassin bug, the same variety as the paler grayish one earlier in this post. Eventually they molt and the black exoskeleton is shed to revel the adult coloration.