Praying Mantises. Which are the Good Ones?

 

Chinese mantis preying on hummingbird © Jeanne Scott-Zumwalt

Chinese mantis,  Tenodera sinensis, preying on a hummingbird
© Jeanne Scott-Zumwalt

Last month I wrote about lady beetles, also called ladybugs, and discussed some of the problems with buying them as biocontrols for your garden pests. Now, it is the turn of another beloved insect, the praying mantid or praying mantis. Guess what? Just as there are many species of lady beetles, there are also many different mantises. The good news is that while lady beetle species number in the hundreds, there are only twenty kinds of mantises.* The bad news is that four or five of those species are not-native and may be causing problems for the native ones.

Mantises are charismatic insects because of their remarkable looks and because they are considered a gardeners friend, eating numerous bugs. Some value them as pets or use them in school projects. The females have the bad reputation of devouring their mates heads, although this is probably largely exaggerated and not as common in the wild as it is with caged ones. They invented Styrofoam long before humans did, more on this below.

European mantis, Mantis religiosa © Huhulenik. Wikicommons

European mantis, Mantis religiosa
© Huhulenik. Wikicommons

Probably, the only one that deserves the name of praying mantis is the European species, Mantis religiosa. However, often we refer to all of them by that name because of the way they hold their front legs as if in prayer, although they hold this posture for more nefarious reasons.

The colors green and brown predominate in most species; colors that serve them well to hide in the foliage. They are not active hunters; instead, they lay in wait for any walking or flying protein passing by, ready to snatch it with those peculiar front legs. The smallest ones are slightly larger than a quarter inch. The larger ones can reach 4.5 in. The females are larger than the males.

Chinese mantis egg case © Beatriz Moisset

Chinese mantis egg case
© Beatriz Moisset

Egg case of the native Carolina mantis © Beatriz Moisset

Egg case of the native Carolina mantis
© Beatriz Moisset

Females lay a large number of eggs enclosed in an egg case made from a frothy substance secreted along with the eggs. This soon solidifies into a firm spongy material, natures version of Styrofoam. The newborns are slightly bigger than an eyelash. So dont make the same mistake a friend of mine did, bringing an egg case home and forgetting about it until she found a crowd of little hatchlings scattered on her desk and climbing bookcases. Mantises are notorious cannibals, if the newborns dont find food soon they start eating each other. So, it shouldnt surprise us that females also eat their own kind.

The native Carolina mantis, Stagmomantis carolina © Kaldari. Wikicommons

The native Carolina mantis, Stagmomantis carolina
© Kaldari. Wikicommons

Native mantises are diminishing in numbers probably because of the invasion by those four or five introduced species. The non-native mantises are larger than most native ones. They either out-compete or eat the ones who were here for millennia before the arrival of the newcomers. You are more likely to see one of these introduced species than one of the natives. I keep searching for native mantises, but have only found an egg case of a Carolina mantis (Stagmomantis carolina).

I have already mentioned one of the most common non-natives, the European praying mantis as big as 3.5 in. It has become rather abundant throughout North America, in large part helped by humans selling it to gardens and pet stores. Connecticut has adopted it as its state insect, despite the fact that it is not native. This shouldnt surprise us, though; seventeen states have chosen the equally non-native honey bee as their state insect.

Chinese mantis © Beatriz Moisset

Chinese mantis
© Beatriz Moisset

The Chinese mantis, Tenodera sinensis, also introduced, is becoming even more common and widespread in large part due to sales. Pet stores usually sell juveniles, called nymphs, or adults, while garden supply stores are likely to provide egg cases during the winter, to be released in the spring. At 4.5 in, it is the largest species in North America, large enough to trap and eat hummingbirds. This is the one that has become iconic and the one most people have in mind when these insects are mentioned.

Now, for the bad news: I already mentioned that these introduced species of mantis have an impact on populations of native species of mantis. They are also not as good for gardens as we are led to believe. I started checking biocontrol distributors. They sell egg cases of Chinese mantis, giving glowing reports on its function as an insect eater. Prices range around two dollars. This makes me laugh. Where I live, I can find countless egg cases in my winter walks. A meadow with goldenrod patches, multiflora roses or brambles allows me to collect dozens in a couple of hours. Why spend money on something you can pick up for free? If you find none nearby, it means that it has not invaded your area. Then, why introduce this invader? Dont we have enough already? Guess what I do with the ones I find: I bury them. I dont want more Chinese mantises around.

Chinese mantis egg case on spruce © Beatriz Moisset

Chinese mantis egg case on spruce
© Beatriz Moisset

The University of Wisconsin gives this advice: Purchasing lady beetles and praying mantids for release in the home garden is not recommended. North Carolina State Universitys factsheet states: Chinese mantids have no demonstrated value in pest management. They give the following reasons: The insects present in most gardens are not abundant enough to satisfy their needs, so they may eat each other or leave the area. They are indiscriminate in their choices and eat a number of beneficial species, as well as pests. Remember that they can even eat hummingbirds, not to mention other praying mantises, bees, etc.

We have learned much from the beginnings of the use of biocontrols. It is important to determine the target pest, first and then choose a specialized predator or parasite that doesnt disrupt the lives of other members of the biological community. The idea of bringing a generalist predator such as a mantis to your garden has turned out to be a bad idea and it is not recommended anymore.

What can we do in our gardens, then? Maintain a habitat that welcomes and sustains the pest enemies as I mentioned in A Healthy Garden is a Buggy Garden. A few more suggestions are scattered through the pages of this blog. If you think that you absolutely need to use pest controls, dont rely solely on the recommendations of distributors; consult university websites that may provide you with more trustworthy information.

Chinese mantis egg cases abound in this meadow © Beatriz Moisset

Chinese mantis egg cases abound in this meadow
© Beatriz Moisset

* These numbers refer to species in North America. See: American Insects: A Handbook of the Insects of America North of Mexico By Ross H. Arnett (p.190).

© 2013 2014, Beatriz Moisset. All rights reserved. This article is the property of Native Plants and Wildlife Gardens. We have received many requests to reprint our work. Our policy is that you are free to use a short excerpt which must give proper credit to the author, and must include a link back to the original post on our site. Please use the contact form above if you have any questions.

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Comments

  1. Debbie says

    Beatriz, What a helpful article. I found a praying mantis in my garden this weekend light brown and @ 3.5 long and was so excited. But now my enthusiasm is tempered. I live in CT and as I was trying to research whether my PM was native or not I did see that CT had adopted the European PM as our state insect. After my surprise at finding out we even had an official state insect, I was sad to realize we didnt have a native insect as our official insect mascot. Wonders never cease in and out of the garden!
    Debbie recently posted..Wordless Wednesday ~ Stripes

    Reply
    • Joyce says

      It distresses me to think that any one of the United States would use a non-native creature as its official insect or bird. I dont think that should be possible. Invasive species are not good though they may appear to be beneficial in the short run.

      Reply
    • Beatriz Moisset says

      I dont know whether to laugh or cry when I read the list of official state insects. It isnt just the European praying mantis. Almost half of the states with an official insect chose the honey bee. Read more here: http://pollinators.blogspot.com/2013/09/official-state-insects.html
      The list of official state flowers isnt much better: roses, camellias and peach blossoms. Oh, well!
      Beatriz Moisset recently posted..Official State Insects

      Reply
  2. Rebecca McMackin says

    Beatriz, fantastic post, as usual. Do you know of any resources for differentiating between mantises? Or their egg sacs?

    Also, is mantid or mantids ever proper usage? I always thought the plural of mantis was mantids.

    Thanks!

    Reply
  3. Theresa says

    Is there a clear way for us amateurs to distinguish between the native ones and the non-natives? I have seen 2-3 in my yard and garden this summer and they have all been 3+ inches long and a lovely green color. And if we have non-natives, should we consider getting rid of them?

    Reply
  4. Beatriz Moisset says

    Rebecca and Theresa:

    Thanks for the comments. Sometimes it is hard to tell mantids or mantises apart, but at 3+ inches you can be almost certain that it is the Chinese mantis. Other mantids are smaller. Perhaps, the only ones that come close in size are the Carolina mantis and some of its relatives in the genus Stagmomantis. These native ones are less common, sadly. I described the main difference in Bugguide with illustrations. The space below the antennae and between the eyes has a different shape. It is broader, more square on the Chinese mantis. Check the pictures in Bugguide.net http://bugguide.net/node/view/12409

    I find it easier to distinguish the egg cases of the Chinese mantis, when compared to any of the others. The Chinese mantis egg case is roundish, with a flattened side. All the other egg cases I have seen are elongated. Once again, pictures would help you. http://bugguide.net/node/view/342391

    You will find additional information on those pages, if you want to dig deeper.

    Personally, I see the non-native mantids the same way I see invasive weeds. I have no compunction picking up and destroying egg cases. Sometimes I see so many that I could be making money selling them, ha, ha!

    Rebecca, after checking a couple of dictionaries, I decided to go with mantis singular and mantises plural, which seem to be the most commonly accepted words. Mantid is actually a made-up word, derived from the scientific name of the family Mantidae. It is the same thing with a number of other words that compromise between the scientific word and one that looks more common; for instance halictid bee for Halictidae, megachilid bee for Megachilidae, and so on. Terminology can be so tricky!
    Beatriz Moisset recently posted..Lady Beetles. Not all are Welcome in the Garden

    Reply
  5. Beatriz Moisset says

    An interesting observation: Adults [monarchs] are killed by the introduced Chinese Mantid Tenodera sinensis Saussure (Orthoptera: Mantidae), which hides among flowers and may ambush dozens of butterflies that visit for nectar (B. Cutting, personal observation). This large mantid is the only insect that I regularly saw consuming adult monarchs. Brian Thomas Cutting. An Evaluation of Butterfly Gardens as Restoration Tools Using the Monarch Butterfly Danaus plexippus (http://udspace.udel.edu/bitstream/handle/19716/11191/Brian_Cutting_thesis.pdf?sequence=1)
    Beatriz Moisset recently posted..Buzz Pollination of Fabaceae Flowers

    Reply
  6. JT says

    This is so disappointing! I had no idea the beautiful big green mantises Ive been seeing are not good guys. I feel like I just found out theres no tooth fairy. :)
    Im in California, but assume the Chinese has invaded here as well.

    Reply
  7. Beatriz Moisset says

    Yes, in fact, they are in the West Coast, too. http://bugguide.net/node/view/12409.
    If it is any consolation, there are about 20 native species of mantises. Sadly, the European and Chinese mantises keep getting more common and the native ones are harder to find.
    I agree that they are beautiful insects and I am sure they fill an important niche in their natural habitat. The problem is that each time we introduce a species, we create problems for the native ecosystems.
    Beatriz Moisset recently posted..Monarch Butterfly, a Case of Mistaken Identity

    Reply
    • JT says

      I know so well the importance of native species and their very interconnected web. I hope I have the courage to kill the Chinese ones I see. This revelation is a huge bummer.

      Reply
      • Beatriz Moisset says

        I dont have the heart to kill the ones I see. But I squash their egg cases without mercy. And I find lots of them.
        Beatriz Moisset recently posted..Buzz Pollination of Fabaceae Flowers

        Reply
  8. JT says

    Beatriz, I loved your post above on monarchs, and the ones on milkweed. Very informative. The little captchas required for postingnot so much. Endlessly frustrating hoop to jump through.

    Reply
  9. Susan Harkins says

    I was totally unaware of the non-native species. I have several in my yard and now Im wondering if theyre the good ones or the bad ones how can we tell? I think you mentioned that the natives are smaller? So, Im guessing the large green and brown ones Im seeing are the bad non-natives. Can we do anything about them? I havent found any egg cases, but Im not sure Id be able to id it from something else! Id like to do the right thing, but unsure what to do. Thanks for the great article.

    Reply
    • Beatriz Moisset says

      Please, read my answer to Rebecca and Theresa on August 7. The links may be helpful. This is the best I can do about telling mantises apart. It isnt easy, even though the ones larger than 3 inches are almost certainly the Chinese ones. I dont bother killing them, however, I crush their egg cases whenever I find them. The egg cases are unmistakable (read the reference above) and can be numerous in meadows with tall grasses or goldenrod, easy to spot in fall and winter.
      What I do recommend is to follow the advice of the University of Wisconsin and the Carolina State University and not buy egg cases of Chinese mantis.
      Beatriz Moisset recently posted..Official State Insects

      Reply
  10. Shala Carter says

    After I learned that Chinese Mantises are related to Roaches, I have never been able to look at them the same way again. And this year I learned that they can eat hummingbirds. So, now on, Im going to have my younger son feed them to his snapping turtle!

    Reply
    • Beatriz Moisset says

      That is a curious view. It is true that mantises in general are related to cockroaches and termites, but it is a distant relationship. For instance butterflies and beetles are more closely related than the groups mentioned above, and look how different they are from each other. Moreover, cockroaches and mantises play important functions in the ecosystem. In my opinion, there are no bad bugs, just creatures trying to make a living and intertwined with the rest of the living community in multiple ways.
      The trouble with the Chinese mantis and the European mantis is that they are not part of the biological community; they havent co-evolved with the other species and they end up causing complications.
      Please, make sure that you dont kill the native mantises; they have a role to play in the community.
      Beatriz Moisset recently posted..The Monarchs Breadbasket

      Reply
  11. Natureobserver says

    There are over 2,000 species of mantises worldwide, about 2 dozen in the US. There are 4 introduced Chinese (Tenodera aridifolia sinensis) narrow-winged, (Tenodera angustipennis), European (Mantis religiosa) and Mediterranean (Iris oratoria), west coast only. They are easy to tell apart from the native ones but only when they are adults. The 2 Tenoderas are from Asia and are 3 to 4 inches. T. sinensis has a yellow spot between the forelegs on the chest, T. angustipennis is orange there.

    http://en.wikipedia.org/wiki/Chinese_mantis

    European has eyespots on the inner part of the forelegs, is about 2 1/2 long:

    http://imagesfromtheedge.com/blog/wp-content/uploads/2010/09/DSC_6738.jpg

    Mediterranean:

    http://en.wikipedia.org/wiki/Iris_oratoria

    this one looks a lot like our several native ones, like the various Stagmomantis species, like S. carolina, S. limbata, and S. floridensis. The biggest native one is Stagmomantis floridensis, 3 inches, but is only found in Florida. Chinese are rare there, so almost all you will see are native. Most of the non-natives are along the eastern half of the US, CT, to GA and west. European only in the northern parts of this. Any of the native ones that are at least 2 inches long can eat monarchs, but are usually not strong enough to overpower a hummingbird.

    Reply
    • Beatriz Moisset says

      Thanks for the additional information. It is much appreciated.
      Beatriz Moisset recently posted..Globetrotting Butterflies

      Reply
  12. Natureobserver says

    Another tip if you want to get rid of chinese egg cases, rather than destroying them, there are plenty people in Europe who want them not for pest control but for the pet trade. In England they rear these in captivity and could use new wild stock to mix up the genetics. You could sell them for a couple of bucks each and ship them there, where importing insects is legal.

    http://www.ukmantisforums.co.uk/forum.php

    Maybe someone there needs some. Also, reptile keepers may want the mantis hatchlings as a food source for tiny frogs or lizards, rather than just wasting the egg case.

    Reply
    • Beatriz Moisset says

      I wouldnt dream of giving that advice. Non-native mantises are just as problematic in Europe as they are here. Sadly, there is no lack of pet stores that sell mantises and other non-native insects in the US. I wish it wasnt so.
      Beatriz Moisset recently posted..The Monarchs Breadbasket

      Reply
  13. Rob says

    I stopped reading after you said there are 20 species of mantises. Try around 2300.

    Reply
    • Beatriz Moisset says

      Hello Rob: Perhaps you were a bit hasty. Too bad you didnt notice from the context that this article is about mantids in North America. Indeed, there are 2,300 species in the world, only approximately 20 of which are found north of Mexico. Please, see: American Insects: A Handbook of the Insects of America North of Mexico By Ross H. Arnett (p.190).

      I feel the need to include a footnote to the article to prevent others from misinterpreting the information the way you did. I hope that now you reconsider and finish reading this piece. Thanks.
      Beatriz Moisset recently posted..The Great Impersonators, flower flies

      Reply
  14. Stephanie Cleveland says

    This was VERY helpful. I didnt know the different types of Mantises. I recently moved from the city to a new home in GA and am getting very into wildlife gardening (Im a birder). I planted a Black Gum Tupelo tree earlier this summer (its been wet and not that hot here this year, so the tree is doing great). Its only about 6 feet tall, but it has lots of green leaves and I have noticed that there is almost always one Mantis on it, and today I saw two. They seem to love the new little tree and I am so happy for them because they are Carolina Mantises. Here is a picture of one turning her head at me: https://scontent-a-sea.xx.fbcdn.net/hphotos-xpa1/v/t1.0-9/13581_10152373693426847_1717100520523604901_n.jpg?oh=5f6c0eab89714e0e8a7bf60cdebbc772oe=543D1696 If I see any of the other kind (hopefully wont) Ill kill them.

    Reply
  15. Carrie says

    Wow! So enlightening! I have recently found what I now know to be three Chinese Mantises, one being a female. She is a beautiful creature and I am sad that she is not home where she belongs. I am going to give her to my Universitys Entomology building, since a lady there was excited at the prospect of breeding her, rather than releasing her. Id rather her not further populating Mississippi with her kind, but I will allow Natalie, and her possibly soon-to-be-mate Gregor to live in captivity at the Entomology building.

    But I will inform the lady that I do not wish them released and if anything would like her returned to me as a pet. Its unfortunate. I will keep an eye out for the egg-sacs from now on, as well.

    Reply
  16. Jodtra says

    It saddens me so much that we caused such a problem. I have fond memories of handling mantises as a child, and even in recent years. They are one of the few insects I dont mind physically on me. And, contrary to popular belief, have never had one bite me.

    Do you have any information about African Mantises? I recently found out about them as well, and was curious about how aggressive they are as a species. Plus how to identify and deal with them.

    It irks me that these creatures are still being sold with such blatant disregard to the impact to such actions. Part of me wants to just go to the store, and buy the whole stock to dispose of them. But, sadly, that would just encourage the business

    Reply

Trackbacks

  1. Bug Egg Casing Mystery Solved | The Meadowlands Nature Blog says:

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  2. The Charless Project | somedayallthisdotcom says:

    [] pair of Monarch and other butterfly wings, strewn among the bushes. The culprits: about 3 huge, invasive mantises, laying in wait among the milkweeds. I had, as it turned out, lured the Charless to their []

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  3. Can you find the Praying Mantis? - Where You Are Planted says:

    [] Like Beatriz Moisset in this excellent article on Native Plants and Wildlife Gardens, I find it laughable that anyone would pay for mantid egg cases. []

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