More Praying Mantis questions from the Question Book

So again, these are some of the questions that I write up through the days while I am out on the land. Curiosities and wonderings, incomplete understandings and unknowns. If I don’t write them down, I’ll never remember to look them up.

I keep seeing them out on the land so I keep wondering about the Praying Mantis and what their habits are.

What do Praying Mantis’ eat?

So what do they eat? Turns out they eat a lot of things, mostly other insects. Crickets, Flies, Grasshoppers, Beetles, Butterflies and Moths, even Spiders (which aren’t insects, but instead Arachnids). They are considered generalist predators of arthopods, but there are a couple sensational reports of them also eating Hummingbirds, Frogs, and small Snakes.

They are ambush predators, and you can sit and watch a Praying Mantis perched quietly, and very still on a Goldenrod stalk while they wait for any passing prey to come within reach of their grasping raptorial forelegs.

And why are they green and brown?

Turns out many people have wondered this for a long time. But more recently, there was an study done in Italy in 2010 to try and finally sort this out. Seems like the answer is still not fully certain, but generally the Mantis’ are changing colours with their moults (shedding exoskeletons) and through that process end up taking on colours of green or brown which more closely resembled the vegetation they were living in.

In the hotter dryer days of summer, more brown Mantis’s were found, and later, as the dry brown vegetation greened up when the rains began falling more in the autumn, more green Mantis’ were found. I think the researchers and writers of the paper can explain better than I can so here is the link.

But there is also the factor that a brown Mantis will tend to hang out in brown vegetation, thus camouflaging better with their surroundings, and not getting eaten. We might find it more difficult to find a brown Mantis amidst green plants because Birds and other predators may be more likely to spot them first.

So really it is a multiplicity of factors impacting the colours of Praying Mantis’.

When do they lay their egg sacs?

Their egg sacs, called Oothecae, are laid in the late summer and early fall, usually along the stalks of tall grasses to overwinter. When temperatures rise in the spring this triggers the hatching and emergence of 100-200 tiny Mantid nymphs, who soon disperse across the fields where they were laid the autumn before so as to reduce population densities in their hatching area… or they are eaten by siblings who exited the oothecae earlier in the hatching/emergence period.

Bonus question: How can you tell the Chinese Mantis and the European Mantis apart?

The Chinese Mantis (Tenodera sinensis) and the European Mantis (Mantis religiosa) are the two most common, though non-native, species of Mantids in North America. I have only recently learned that the Chinese Mantis has vertical stripes along their face, running from the base of the antennae down to the upper edge or “upper lip” of the mouth, where as the European Mantis does not have these stripes on their faces.