Tag Archives: garden

Chinese mantids eat monarch butterflies

This post is a PSA for anyone keen on helping monarchs: if you find Chinese mantids (Tenodera sinensis) in your yard, kill them. As proof, below is a photograph of one that had just snagged a monarch visiting my swamp milkweed. The monarch is fine, by the way. After I intervened she flew off, then came back within seconds and resumed ovipositing.

Monarch butterfly captured by a Chinese mantid (Tenodera sinensi

But unless you’re observing your milkweed patch obsessively, you’ll probably never catch a Chinese mantid in the act. But you can infer their presence by piles of monarch wings (i.e., no body attached). No other animal does this to monarchs.

Monarch butterfly wings left by Chinese mantid predation

And caterpillars are just as susceptible. Here’s a Chinese mantid I interrupted just as it was about to strike:

At base of milkweeds was a pile of monarch butterfly wins. Swarthmore, PA.

Chinese mantis can be easily distinguished from any of the native mantids by the presence of a yellow dot in between the forelegs.

Chinese mantis (Tenodera sinensis)

If you find an ootheca (egg case) of this species, crush it. The oothecae have an irregular, messy surface that looks like a blob of brown, poorly-applied insulating foam. Oothecae of the native Carolina mantis are much smoother and streamlined (pic).

First-instar nymph of Chinese mantis (Tenodera sinensis) on ootheca

If you’re like most people (including myself), you grew up believing that mantids are a pesticide-free way of reducing garden pests. How could thousands of web sites be wrong?? The truth is, however, that Chinese mantids are so large that they tend to only eat large insects, and that usually means mainly butterflies, not aphids or other species that are tiny. So if you hate butterflies, by all means encourage Chinese mantids in your yard. But if you like butterflies in your garden, kill the Chinese mantids. And don’t just relocate them, even though that seems like the friendly, eco, green, peace-loving thing to do. Moving introduced, invasive species to another location simply facilitates further spread. It’s like transporting your rabid, aggressive pit bull to a different part of the city (“I didn’t want to euthanize it. Maybe it will thrive in a different neighborhood!”).

FYI, Chinese mantids also eat hummingbirds, plus other birds that are even bigger. The authors of that linked paper conclude,

“Our compilation suggests that praying mantises frequently prey on hummingbirds in gardens in North America; therefore, we suggest caution in use of large-sized mantids, particularly non-native mantids, in gardens for insect pest control.”

Italics mine.

Boating to Bartram’s Garden

One of the gems of Philadelphia is the former estate of John Bartram, a world-renowned botanist and buddy of Ben Franklin (who flew his kite there, I gather). Back in the day, his garden along the Schuykill River was filled with rare and interesting plants collected from different regions of the colonies, had a heated greenhouse, and was a destination for anyone of import who happened to be in the area.  The garden and buildings today survive on a small patch of the former property, an island amid urban squalor and decaying industrial sites.  You can drive there, but I took a boat from downtown Philadelphia (visit www.schuylkillbanks.org for details).  In case you are too far away to do the same, some photographs are below (mouseover reveals description; click to see larger).  The most notable part of the house tour was the thriving population of camel crickets on the ceiling.  The tour guide was annoyed that everyone was so interested in them. If you’re in the area and want to go, get details at bartramsgardens.org. The anniversary of his death is this Sunday (September 22nd).

Colin Purrington Photography: Philadelphia &emdash; Boat to Bartram's Gardens on the Schuykill River

Colin Purrington Photography: Philadelphia &emdash; Bartram House

Colin Purrington Photography: Philadelphia &emdash; Strange staircase at Bartram House

Colin Purrington Photography: Philadelphia &emdash; Camel crickets on ceiling of Bartram House

Colin Purrington Photography: Philadelphia &emdash; Specimens on desk in Bartram House