Praying Mantis: Friend or Foe?

Praying mantis on a wanted poster

Young praying mantis on clematis leaf

I took the above photograph a year ago of a young praying mantis (3/4 inch long) perched on one of my clematis leaves.  This morning I was out in my garden and I came across a very large praying mantis (3 1/2 inches in length).  I immediately called my husband to come over to keep an eye on it while I ran inside for my trusty digital camera. 

Here are a couple of photos I took, but it was hard to capture more since they are rather camera shy:

Adult Praying Mantis

Here it is trying to escape my attempts at being an entomological paparazzi:

Praying mantis on the run

Many of us like to label the insects we find in our garden as friends or foes.  For instance, if we find lacewings or ladybeetles (aka ladybugs) we are pleased with their presence, whereas, if we come across aphids, thrips, leafhoppers, etc., we are dismayed.  To some, praying mantises are seen as possibly a beneficial candidate for natural pest control, especially to those companies that sell them and other insects such as ladybeetles, decollate snails, etc. for that purpose.

Yes, praying mantises will eat the bad guys: grasshoppers, flies, beetles, aphids, moths, caterpillars, crickets, etc. in your garden, but they do not stop there.  Apparently they have no moral compass guiding their dining palette because they have no problem partaking on their fellow mantises.  In their voracious quest for more and more food they also chow down on unsuspecting beneficial insects including: butterflies, bees, lacewings, ladybeetles, small frogs, small lizards, etc. that have the misfortune of crossing a path where they will be stealthily ambushed.  In other words they will eat anything they can snare with their two specialized, spiked forelegs.

Depending on which stage of development they are in (nymph, adolescent or adult) determines what size prey they will hunt.  When they are younger their victims are smaller in size, so they could be construed as more helpful to us then since the eat aphids, mosquitoes, ants, etc.  However, when they become adults all bets are off because that is when they will still consume tons (okay maybe a slight exaggeration) of insects as well as supplement their diet with the occasional small invertebrates like: frogs, lizards, mice and/or birds. 

I will admit I have never been a fan of these cannibalistic insects (who prefer to eat their prey while still “alive”), so when I have come across one in the past I do what according to folklore the female supposedly does to her male partner in mating season…I cut off its heads.  Okay, I am sure I have caused some of you to think I am horrid, but after I discovered they will eat hummingbirds and/or their little nestling babies, I feel absolutely no remorse sentencing these sadistic creatures to the guillotine for a beheading!  When I found this out I immediately placed them at the top of my gardening “Wanted Dead or Deader List”.  It is one thing to eat small snakes, but I was totally disgusted when I saw two pictures of my favorite little flying gems being devoured by this pernicious predator on the website: Praying Mantis Makes Meal of a Hummer

If you have a strong stomach and want to read a gruesome account of how they devour their victims see the section on Diet on the IPM Fact Sheet on Praying Mantises.

So, is the Praying Mantises a friend or a foe?  In my opinion the answer to the question is “FOE”!  Not only do I want my garden to be a safe-haven for my clematis, but I also want it to be a sanctuary for my cute, little hummingbirds.  I have no desire for a non-selective killing machine residing in my garden.  They are the masters of camouflage (as they can change colors which will mimic their surroundings and are most often mistaken for a twig or stick), so I will now be all the more vigilant for any and all stages of praying mantis whether they be nymphs, adolescents or adults. Their egg casings are fair game as well and I will swiftly give all of them a royal execution to keep peace in my Queendom. 

Praying Mantis Egg Casings

In the past I have seen pictures of praying mantises nests officially known as oothecae.  They resemble a round, spongy sack and are usually perched on a small twig.  However, while researching this article I found that some of their nests (like the ones found in California) can also be flatish and oval-shaped (approximately 1 ¼ inches long) and are most often laid on the south side of an object or a twig.  If you want to see a picture of this type of casing (until I can find another one to take a picture of) please visit: It’s Not Work, Its Gardening! or All Gods Creatures - Big & Small. I have come across the latter type of cocoon a couple of times in my garden and I had no idea which potential insect I was encountering. To be honest, since it had a rather alien-like appearance that made me feel queasy at the time I decided to surgically eliminate its insides with my clippers and did so each time I found another one.  Looking back now I suppose I should have done more due diligence to find out which insect these casings belonged to, but having now discovered what the contents would have produced, I feel quite relieved that I disposed of them at the time.

FYI: Fall is the time that the females lay their egg casings (which can each potentially hold up to a couple of hundred eggs).  So, if you too would like to nip praying mantises in the bud, now is the time to be on the lookout for these casings so you can do what it takes to carry out the sentence on the wanted poster and give yourself the peace of mind knowing your garden will be mantis-free.


Editor’s note: For an update and pictures of a casing found in my garden please visit: