Tag Archives: butterfly

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.

Hummingbird and snowberry clearwing moths

Here are some photographs of the hummingbird clearwing moth (Hemaris thysbe) and the snowberry clearwing moth (H. diffinis).

Colin Purrington Photography: Insects &emdash; Hummingbird and snowberry clearwing moths

Day-active, colorful moths are rare enough, but these take it to the next level in their uncanny mimicry of hummingbirds and bumblebees, respectively. The mimicry presumably protects them from being eaten by predators such as crab spiders, praying mantids, and birds. In addition to the obvious behavioral and morphological resemblance to hummingbirds and bumblebees, the moths also make a slight humming noise that completes the disguise. The noise could easily be an unavoidable consequence of hovering flight (approximately 30 beats/second), but I wouldn’t be at all surprised if their wings are rigged in some way to exaggerate the noise. I’d love to know the answer to that. My other burning question is why the hummingbird clearwing moth has clear wings at all … I would expect selection to favor individuals that did not lose scales, because such a mutant would more resemble a hummingbird, which has opaque wings. I’m guessing that reason is not because fully-scaled wings are too heavy — the hummingbird hawk moth (Macroglossum stellatarum) in the Old World has opaque wings and can manage 70-90 beats/second (wow). I wonder whether a fully scaled wing might damp the humming sound. All photographs were taken at Natural Lands Trust’s Hildacy Farm Preserve in Media, Pennsylvania. Oh, and happy National Moth Week.

Colin Purrington Photography: Insects &emdash; Hummingbird clearwing moth (Hemaris thysbe) with unfurling proboscis

Colin Purrington Photography: Insects &emdash; Hummingbird clearwing moth (Hemaris thysbe) showing wing veination

Colin Purrington Photography: Insects &emdash; Hummingbird clearwing moth (Hemaris thysbe) nectaring

Colin Purrington Photography: Insects &emdash; Hummingbird clearwing moth (Hemaris thysbe) nectaring at wild bergamot

Colin Purrington Photography: Insects &emdash; Hummingbird clearwing moth (Hemaris thysbe) nectaring at wild bergamot

Colin Purrington Photography: Insects &emdash; Hummingbird clearwing moth (Hemaris thysbe) arriving at flower

Colin Purrington Photography: Insects &emdash; Hummingbird clearwing moth (Hemaris thysbe) nectaring at wild bergamot

Colin Purrington Photography: Insects &emdash; Snowberry clearwing moth (Hemaris diffinis)

Colin Purrington Photography: Insects &emdash; Snowberry clearwing moth (Hemaris diffinis)