what happens to praying mantises in the winter

what happens to praying mantises in the winter

 

 

You Spent All Summer Watching Them—Now They've Vanished. Where Did They Go?

All summer long, they were there. Perched on your rose bushes, clinging to the sunflower stalks, their triangular heads swiveling to watch you as you gardened. The praying mantises were a constant, fascinating presence. But then the temperatures dropped. The leaves fell. The first frost painted your garden silver. Suddenly, your garden's charismatic predators are nowhere to be found. It's a question that puzzles gardeners every year as winter settles in: what happens to praying mantises in the winter?

Do they burrow deep into the soil like some insects? Do they hibernate under piles of leaves? The answer reveals one of nature's most remarkable survival strategies—a strategy that involves sacrificing the entire adult generation to ensure the next lives on. Understanding this cycle is not only fascinating but also crucial for gardeners who want to support these predators in their yards year after year. Let's uncover the winter secret of the praying mantis.

The Cold, Hard Truth: Adults Don't Survive

Let's start with the most important fact: adult praying mantises do not survive the winter [citation:1]. As ectotherms, they cannot generate enough internal heat to stay active in the cold [citation:1]. When temperatures drop and frost arrives, their biological clock runs out. According to Iowa State University Extension, "Adults die of old age or freezing, whichever comes first" [citation:2].

The adults you see in late summer and fall are the final chapter of the year's story. They have one primary mission before winter arrives: reproduce and ensure the next generation carries on [citation:2]. The University of California's Integrated Pest Management program confirms that "Overwintering is as eggs. Adults and nymphs generally do not survive the winter" [citation:6].

It's a harsh reality, but it's also an incredibly efficient evolutionary strategy. Instead of wasting energy trying to survive the cold, the species invests everything in creating protected offspring that can endure until spring [citation:2].

The Egg Case: Nature's Winter Survival Pod

So, if the adults die, how does the species continue? The answer lies in a remarkable structure called an ootheca [citation:1]. When you ask what happens to praying mantises in the winter, the true answer is: they don't go anywhere—their eggs do, tucked away in a perfectly designed winter shelter.

In the fall, the female mantis deposits her eggs in a frothy secretion that hardens into a sturdy, styrofoam-like case [citation:1][citation:9]. This case, the ootheca, is a masterpiece of natural engineering. It protects the eggs from freezing temperatures, ice, snow, and even some predators [citation:3][citation:7]. Depending on the species, each ootheca can contain anywhere from 100 to 300 eggs [citation:1][citation:3][citation:5].

Here's where you can find these egg cases during the winter months [citation:1][citation:7][citation:9]:

• On twigs and branches: Females often attach them to sturdy plant stems, tree branches, and shrubs.
• On structures: They can also be found on walls, fences, the sides of houses, and under eaves.
• Hidden in plain sight: The cases are brown or tan and blend in remarkably well with bark and dead vegetation.

Identifying Different Mantis Egg Cases

Not all oothecae look the same. If you're searching your garden this winter, you might come across cases from different species. Here's how to tell them apart based on expert sources [citation:1][citation:7][citation:9]:

Species	Egg Case Appearance
Chinese Mantis (Tenodera sinensis)	Large, round, about 1.5 inches long, often wrapped around a twig like foam insulation [citation:1][citation:7].
Carolina Mantis (Stagmomantis carolina)	Smaller and flatter, tan to light brown, with a distinct white or gray band running down the center [citation:1][citation:7].
European Mantis (Mantis religiosa)	Smaller than Chinese mantis, often found on grass stems or low vegetation [citation:9].

When Spring Arrives: The Great Hatch

Inside those tiny egg cases, life is waiting. The eggs remain in a state of diapause (a kind of hibernation) throughout the winter [citation:5]. As temperatures warm in late spring, usually from late May to early June, the nymphs begin to emerge [citation:2][citation:3].

When they hatch, they don't all crawl out at once. Tiny nymphs emerge in a swarm, dropping from the case on silken threads [citation:1]. They are miniature versions of the adults, minus the wings, and they are born hungry [citation:1][citation:10]. In fact, their first meals often include their own siblings, as cannibalism starts almost immediately [citation:1][citation:2][citation:7]. This is nature's brutal way of ensuring only the strongest survive to continue the cycle.

These surviving nymphs will spend the summer growing, molting, and hunting, eventually maturing into the adults we see in late summer [citation:3]. The development from egg to adult takes about 3 months [citation:3].

The Rare Exception: Warmer Climates

While the egg-case strategy holds true for most praying mantises in temperate regions, there is a rare exception documented in scientific literature. A 1984 study from New Zealand documented that some adult and nymph mantises of the species Orthodera ministralis successfully survived a mild winter outdoors in Auckland [citation:4].

Researchers found that overwintering nymphs were not disadvantaged, and some adults probably survived for at least 7 months [citation:4]. However, this occurred in a subtropical climate and is considered unusual. For the vast majority of North American gardeners, you should assume the adults will not make it through the winter [citation:2][citation:6].

How You Can Help: Protecting Egg Cases

Now that you know what happens to praying mantises in the winter, you can actively support their life cycle in your garden. Finding an egg case is like discovering a natural time capsule of pest control. Here's what you should do, according to multiple extension services [citation:2][citation:7]:

If You Find an Egg Case Outdoors

First, congratulations! You've found a source of future pest control. The best thing you can do is leave it where it is, as long as it's in a safe location. If you must move it, carefully cut the twig and relocate it to a sheltered spot. However, be very careful not to bring it into a warm house [citation:2].

Critical Warning: If you bring an egg case indoors, the warmth will trick the eggs into hatching in the middle of winter (January or February) [citation:2][citation:9]. At that time, there will be no food for the tiny nymphs, and they will quickly starve or eat each other [citation:2]. If you want to move an egg case, store it in an unheated garage, porch, or shed where it experiences near-outdoor temperatures [citation:2]. Bring it inside in mid-spring to watch the hatch, then release the nymphs immediately.

Never put an egg case on the ground; the eggs inside will quickly be consumed by ants [citation:7].

Adding Egg Cases to Your Garden

If you don't find any egg cases in your yard, you can purchase them from garden centers or online sources. This is a fantastic way to boost the mantis population in your garden. Think of these purchased egg cases as nature's free samples of biological pest control—a starter kit for a healthier garden ecosystem. By introducing them, you're ensuring a generation of tiny predators ready to hunt pests in the spring, acting like free samples of natural defense for your plants.

When you release the nymphs, scatter them around your garden so they have space to hunt and less competition for food (and less cannibalism) [citation:2]. They will immediately begin preying on small pests like aphids and thrips.

Survival Rates: The Brutal Math of Nature

It's important to have realistic expectations. Nature is harsh, and mantis survival rates reflect that. It is estimated that only one-fifth of hatched nymphs survive to adulthood [citation:5]. Most will die from starvation, predation, or cannibalism. They are territorial, and by the end of summer, usually only one adult remains from an entire egg case [citation:7].

This is why the female lays hundreds of eggs—to ensure that at least a few make it through the gauntlet of predators, weather, and their own siblings to continue the cycle.

Conclusion: The Cycle Continues

So, what happens to praying mantises in the winter? They don't go anywhere—at least, not the adults you know. They live out their final days in the fall, mate, and leave behind a legacy sealed in a tiny, foam-like case. The adults perish with the frost, but their species survives, waiting patiently for the warmth of spring to release the next generation of garden guardians.

This winter, take a walk through your garden. Look closely at the bare branches, the fence posts, and the dried flower stems. You might just spot a mantis egg case—a promise that life will return when the weather warms. And when you see that first tiny nymph next June, you'll understand the incredible journey it took to get there.