Praying mantises, known for their unique appearance—large compound eyes, a triangular head, and powerful, spiny forelegs—are effective hunters. Their ability to remain motionless and blend into surroundings makes them formidable predators.
Praying Mantis Presence in Wisconsin
Praying mantises are found in Wisconsin, with established populations across the state. Sightings are becoming more common, especially after mild winters. While the native Carolina mantis is occasionally seen, most mantises observed in Wisconsin are non-native species. Their presence is largely due to accidental introductions, often through nursery stock, and the sale of their egg cases for garden pest control.
Common Species Found in Wisconsin
Three mantis species are present in Wisconsin: the native Carolina mantis, the European mantis, and the Chinese mantis. The Carolina mantis (Stagmomantis carolina) is the smallest of the three, typically reaching about 2 inches in length and having a mottled, dusty brown or grayish coloration. This species prefers warmer climates, so its appearance in Wisconsin is less frequent. The European mantis (Mantis religiosa) is a non-native species, measuring approximately 3 inches long and appearing pale green or tan. A distinguishing characteristic is a black or black-and-white spot located at the base of each front leg. The Chinese mantis (Tenodera sinensis) is the largest and most commonly encountered species in Wisconsin, often reaching 3 to 5 inches, and sometimes up to 6 inches in length. It can be bright green, light brown, or tan, sometimes with a green stripe along the outer edges of its folded wings. Both the European and Chinese mantises were introduced to North America in the late 1800s.
Where and When to Spot Them
Observing praying mantises in Wisconsin is most likely from late August through October, when adults reach maturity. They inhabit various environments, including gardens, meadows, and areas with tall grasses and shrubbery. Mantises are ambush predators, blending into vegetation while waiting for prey. They are also attracted to lights at night, making porches and deck lights common sighting spots.
Adult mantises perish during colder months, but their egg cases, called oothecae, survive the winter. These frothy, styrofoam-like cases, containing dozens to hundreds of eggs, attach to plant stems, twigs, or gardening stakes. Nymphs emerge from these cases in late spring or early summer, depending on temperatures, and disperse to feed.
Their Role in the Local Ecosystem
Praying mantises are generalist predators, consuming a wide array of insects they can overpower. Their diet includes flies, beetles, crickets, moths, grasshoppers, and sometimes smaller beneficial insects like bees and butterflies. This predatory behavior can aid garden pest control, as they target common pests such as aphids and caterpillars. However, their indiscriminate feeding means they do not specifically target pest species.
Mantises serve as both predators and prey within the food web. While efficient hunters, they can fall victim to larger animals such as birds, spiders, bats, and even fish if in water. Despite being non-native, their populations in Wisconsin are not considered invasive, as they do not cause widespread negative impacts on the ecosystem. Their presence contributes to insect diversity and predatory dynamics within local environments.