Tag Archives: caterpillar

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. 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:

Colin Purrington Photography: Insects &emdash; Chinese mantis with monarch caterpillar

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.

Banded tussock moth

Banded tussock moth (Halysidota tessellaris) caterpillar with stemmata peeking out from behind the anterior tufts. The second photograph shows the barbed setae, which will eventually be detached and rewoven into the cocoon.

Colin Purrington Photography: Insects &emdash; Banded tussock moth (Halysidota tessellaris) caterpillar

Colin Purrington Photography: Insects &emdash; Barbed setae of the banded tussock moth (Halysidota tessellaris) caterpillar

Checkered-fringe prominent

Found two of these caterpillars on blackberry last week. I really should have brought them back home to see if they would eat morning glory leaves. Apparently they hate morning glory despite being named Schizura ipomoea (and thus traditionally called a morning glory prominent). Also sometimes referred to as the false unicorn prominent. You can distinguish the checkered-fringe from the unicorn prominent (Schizura unicornis) on the basis of head striping (among other differences). But don’t handle them during the identification process: they spray mixture of formic and acetic acid from that dorsal horn on abdominal segment one, and that will hurt and make your skin blister.

According to one study, these caterpillars coat the tissues of freshly-girdled tree stems with fluid. The authors guess that the fluid contains something that blocks the de novo production of chemical defenses in the leaves. This “chew and spit” behavior seems to be common in the family (Notodontidae). More details and papers on the behavior at David Dussourd’s website.

Colin Purrington Photography: Insects &emdash; Checkered-fringe prominent (Schizura ipomoeae)

Colin Purrington Photography: Insects &emdash; Checkered-fringe prominent (Schizura ipomoeae)