Ask a Master Gardener

Praying Mantids

10/5/21

I have several praying mantids in my garden. Do I need to be concerned? EW

Praying mantids are part of the order Mantodea which is where the mantid part of their name comes from. The praying part comes from how the position of their front legs makes it look like they are praying. In reality you will hear this insect referred to as a praying mantis or praying mantid. Mantid in Greek means soothsayer or prophet so let’s talk a little bit about this insect called the praying prophet.

While those front two legs might look like they are praying, they actually have long, sharp spines on them that are used to capture their prey. These spines fit into grooves on the opposing parts of the legs when at rest. Whenever we see an insect with “pinchers” like this, this lets us know the insect is a predator. As such, these predators will eat flies, beetles, crickets, moths, and grasshoppers among others. In more tropical locales mantids are larger and can dine on lizards, frogs, and even hummingbirds.

Their hunting technique is pretty simple; wait quietly and motionless until an appropriate meal walks by and then reach out and grab it. They don’t appear to hold any respect for their fellow mantids either, as another praying mantid walking by is looked upon as equally delicious. In nature’s food chain, mantids are food for birds, spiders, bats, or even fish if they happen to tumble into the water.

Many have probably heard the story about the female praying mantid eating the head off her unsuspecting mating partner. This can happen in the wild sometimes, but it is not the norm. Some say the praying mantids used in the study that birthed this common myth were underfed. Hard to know, but I think the takeaway here is that if you are an insect, your best plan is to keep your distance from praying mantids.

After mating in the fall, female mantids lay dozens to hundreds of eggs. These eggs are mixed in with a foamy solution that hardens to provide a protective shell in which the eggs overwinter. The adults die shortly thereafter. In the spring, the baby mantids hatch and look like small versions of the adult.

This is probably a good time to talk about growth stages in insects. For the most part we categorize insect maturation processes into two categories: complete metamorphosis and incomplete metamorphosis. Complete metamorphosis occurs in butterflies for example as there are four distinct stages: egg, larvae, pupae, and adult. In each of these stages, the insect looks strikingly different than the previous stage.

In incomplete metamorphosis there are three stages: egg, nymph, and adult. In incomplete metamorphosis, after hatching the insect looks very similar to their adult counterparts just smaller as they grow through several instars (growth stages). At the end of each instar the insect sheds its skin and emerges a little bigger. This continues until they reach adulthood. Initially, the young praying mantid nymphs do not have wings but develop them later in the process.

Praying mantids are known for their elongated thorax (their neck) and their triangular head with its large eyes. Their mouths can look like they are smiling as we look at them, but we are probably anthropomorphizing (dictionary time). Praying mantids are in fact the only insect that can turn their heads from side to side without moving any other part of their body. This head can swivel almost all the way around which seems to make us feel like they are looking at us or perhaps curious, when in reality they are probably just sizing us up as a potential meal.

While worldwide there are approximately 2000 varieties of mantids, North America is home to 17 of those varieties. Interestingly, praying mantids are typically colored in ways that match their primary habitat. This camouflage helps them while hunting food because their prey likely never sees them until it is too late.

It would be easy to put praying mantids in the “beneficial insect” category because they eat other insects. However, certain challenges accompany this strategy since they are really indiscriminate eaters. For example, we are all familiar with lady bugs (aka lady beetles). Lady beetles are in the beneficial insect category because they will eat aphids but will leave monarch caterpillars alone. In contrast, praying mantids will eat most any insect (including pollinators) with the same intensity as they will eat insects, we would consider pests. So, the temptation to call them “beneficial” comes with a caveat.

Because of their ability to blend in with their surroundings, you may have praying mantids in your landscape and not know it. To encourage praying mantids in your garden you will need to limit your pesticide usage. Even if you are careful with your applications, you may not be able to exclude praying mantids from your pesticide spray since they are so good at remaining unseen.

While the praying mantid can take out a pollinator now and again, I still consider them a welcome guest in my garden. Plus, they are just fun to watch and that sounds beneficial to me. Happy gardening.

You can get answers to all your gardening questions by calling the Tulsa Master Gardeners Help Line at 918-746-3701, dropping by our Diagnostic Center at 4116 E. 15th Street, or by emailing us at mg@tulsamastergardeners.org.

Photo: David Cappaert, Bugwood.org