Praying mantises are formidable generalist predators, recognized by gardeners as beneficial insects for natural pest control. Their presence in a yard signifies a healthy ecosystem, as they consume common garden pests like aphids, flies, and caterpillars. Introducing these fascinating hunters requires a practical approach to their acquisition and habitat needs.
Acquiring Mantises: Purchasing Egg Cases
The most reliable method for introducing praying mantises is by purchasing their egg cases, known scientifically as oothecae. These foam-like structures, which can contain 50 to over 200 developing mantids, are commonly available through online suppliers and garden centers. Order oothecae in late winter or early spring before the weather warms significantly to ensure the cases remain dormant and hatch outdoors at the appropriate time.
Many commercial suppliers offer egg cases primarily from the non-native Chinese mantis (Tenodera sinensis) or the European mantis (Mantis religiosa), alongside the native Carolina mantis (Stagmomantis carolina). Store the ootheca in a cool, dry place, such as a refrigerator or unheated shed, until average daytime temperatures consistently reach 60°F or higher. Storing the case indoors in a heated home can prematurely trigger hatching, resulting in hundreds of tiny mantis nymphs with no immediate food source.
Optimal Placement and Care for Egg Cases
Proper placement of the purchased ootheca is critical to maximize the hatching success rate and the subsequent dispersal of the young nymphs. The case should be secured to a sturdy plant stem, branch, or fence post about one to two feet off the ground. This elevated position protects the case from ground-dwelling predators and excessive moisture. Use twist ties or twine to gently fasten the case, taking care not to pierce or damage the foam structure.
The location should also be sheltered from direct, harsh sunlight and heavy irrigation or rain. Constant saturation can promote mold growth or weaken the protective shell. Once positioned, the case requires no further hands-on care and will hatch naturally when the environmental conditions are right.
Creating a Welcoming Habitat for Native Mantises
For long-term success and to attract native species, focus on creating a structurally diverse and chemical-free environment. Praying mantises are ambush predators and require dense vegetation, such as tall grasses, shrubs, and flowering plants, to serve as camouflage and hunting perches. Plants with complex structures, like dill or cosmos, provide excellent cover and attract the smaller insects that mantis nymphs need for sustenance.
The elimination of broad-spectrum pesticides is necessary, as these chemicals indiscriminately kill mantises along with the pests they target. Maintaining a healthy, diverse garden with varied insect life ensures a constant food supply, encouraging mantises to stay and reproduce. Allowing leaf litter to accumulate and minimizing aggressive tilling also provides sheltered spaces for overwintering and egg-laying sites.
The Mantis Life Cycle and Garden Presence
The mantis life cycle begins when the overwintered ootheca hatches, typically in late spring or early summer, releasing a large number of tiny, wingless nymphs. These young mantids are highly vulnerable and immediately disperse into the surrounding vegetation, which is why gardeners often do not see the initial hatching event.
They will begin to molt, or shed their exoskeleton, multiple times throughout the summer as they grow larger. Each successive molt increases their size and their ability to tackle larger prey, advancing them through various stages called instars.
Mantises reach full maturity and develop wings by late summer or early fall. At this point, the adults will mate, and the females will lay new oothecae on sturdy plant material before the first hard frost, completing their annual cycle. The adult mantises die off after reproduction, leaving the new egg cases to survive the winter and repeat the process the following spring.