Invasive Mantid Removal

Chinese Mantis perched in purple flowers at Stoneleigh: a natural garden

Early spring is the season for removing Chinese mantis oothecae (or egg cases) at Stoneleigh: a natural garden.

Introduced to the United States in the 1800s. Unfortunately, these large predators are generalists with voracious appetites that will eat anything they can catch, including butterflies and bees. Considering Chinese mantids are nearly twice as large as our native Carolina mantis (Stagmomantis carolina) and much more abundant, they can have a greater impact on our beneficial insect populations. Chinese mantids (Tenodera sinensis) are non-native insects that were accidentally introduced to the United States in 1896 in Mt. Airy, Pennsylvania.

At Stoneleigh, we’ve been removing egg cases from our meadow and other perennial-dominated areas for several years. Our first year, we removed more than 350 Chinese oothecae from our meadow alone.

This year, volunteers and staff scoured several large garden areas and only found 68! By decreasing the population of this generalist, non-native predator and increasing the number of native plants, the garden is becoming more hospitable for our native butterflies, bumblebees, and pollinators every year.