Tag Archives: invasive

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 (see, “Identifying mantid egg cases in Pennsylvania“).

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.

Instragramming invasive species in Hawai’i

During my recent trip to Hawai’i I got to wondering how conservation organizations use Instagram to educate the public about invasive species. A quick search pulled up several groups that seem involved, at least occasionally, and I’ll list here just in case you want to follow them (# followers in parentheses):

hawaii-invasive-species-instagramPart of my reason for wasting time on the above was because when I posted a photograph of an introduced frog, I wasn’t sure if anyone on Instagram might care. Potentially, there might be a group or two that might want to be mentioned, in the off chance that a species hadn’t been noticed at that particular location. Not being a native (I was a baby when I lived there), I had no idea which groups to tag, though, so all I did was add some hashtags for the species name as well as #invasive #introduced #nonnative … with the hope that somebody might find it useful someday (unlikely). But the process got me wondering how groups use Instagram to get the word out on how to control invasives. Here are some thoughts on how to do it, with apologies to the groups who are already doing it:

  1. To build buzz about your organization and its goals, repost images of others that show the species you are trying to control. People love to have their images reposted or their accounts mentioned. You can find these images by following people (duh), or by searching Google for Instagram photos with particular keywords (e.g., site:instagram.com coqui kauai). The routine is just this: ask them if it would be OK to be reposted/featured … and then give them credit by including Instagram handle (i.e., don’t just give the photographer’s name).
  2. If you don’t want to feature other people’s images, at least patrol other people’s posts that relate to invasive species, endemics, restoration, etc. For example, if somebody posts an adorable photograph of a small frog and says, “Love this little guy; going to send to my uncle on Kauai for his birthday!” … you can urge them not to do that. Or, when somebody posts about clearing invasives from property, you can say thanks (and perhaps invite them to a volunteer day if you’re group is local). And it’s not just people making posts about invasives … many companies are active in promoting pono and have thousands of active followers (@southmauispearfishing, e.g., has *dozens* of posts about invasive roi and what to do about them). The more you interact by favoriting and commenting, the more people on a particular island will see your organization’s work as important and worth supporting.
  3. If your organization has volunteer work days, add an “Instagram name” column to your sign-in sheet. Then mention each person when you post photos from the event (you should do that!). People love to be publicly thanked. Example. Another example.
  4. In your bio and in your posts, remind folks to tag their own images with #invasive #hawaii (or whatever) and species name so that the posts can help educate their followers. Example. Example. You can also dream up custom hashtags such as #hawaiiinvasive if you want (that’s from @kauaiisc, by the way).
  5. When you make presentations about invasives at local schools, show your Instragram handle at start and end. Young adults increasingly don’t care about your web site, your twitter feed, or your phone number but you might get them to follow on Instagram.
  6. Award prizes to people reporting or posting certain kinds of images. People love contests. For example, send some swag to person who posts best selfie with gold dust day gecko (example).
  7. If you have a Facebook page, add a tab for your Instagram feed. It’s easy. You should also automatically add your Instagram posts to your timeline.
  8. If you include a phone number in your bio for reporting a particular species, include an area code in case clueless tourists see call to action. Repeat this number in posts, too … because somebody might not bother to visit your actual home page.
  9. Check Instagram regularly to see whether anyone has posted an image of a species of special concern. For example, you can run a search for “site:instagram.com snake hawaii” to patrol for snake sightings (the search results are mainly Hawaiian shirts with snakes). There used to be several ways to automate such Instagram searches and receive emails … but Instagram blocked them.
  10. If your organization doesn’t have an Instagram account, fix that.