Even though I know that praying mantises are not native to New England and that they are not beneficial (due to their voracious appetites for anything small and alive) I still wait for them to show up every fall in the weedy edges of our driveway. There is a term, charismatic megafauna, used to describe wildlife that everyone tends to love − big (hence the ‘mega’), good-looking animals that are just super-cool. These are the species you see on posters promoting conservation-pandas, tigers, killer whales and their ilk. I think of praying mantises in the same vein-but instead of ‘mega’ they are charismatic microfauna. Something about the human-like way they clasp their arms in a way we take for prayer. The way they follow your movements with a tilt of their head and those intelligent, mesmerizing, predatory eyes. In fact, they are so popular with humans that despite being non-native they are the Connecticut state insect!
The praying mantis you are most likely to find around here is the European Praying Mantis (Mantis religiosa). As the name suggests, they are native to Europe and arrived here over 100 years ago, released in Rochester, New York in 1900 to help control pests. We now know that this isn’t a great idea − it is better to encourage native predators instead of introducing a non-native, voracious killing machine that indiscriminately preys upon both pests and beneficial insects. Since they also have no issues eating each other, populations tend to stay small.
Praying mantises are ambush predators, lying in wait for prey, striking out with lightning speed, using those spines on their forearms to help snag prey. One of their coolest (I think) adaptations that helps them both detect prey and predators is a metathoracic ear on the underside of their body that can detect both high and low frequencies, even ultrasound. This helps them hear their prey move towards them and also allows them to detect would-be predators, for example the ultrasound squeaks of incoming bats. Interestingly mantis hearing predates the appearance of bats (approximately 63 million years ago) so it’s just a happy coincidence for the praying mantis that it has this bat-avoidance superpower.
This is the perfect time to look for praying mantises. They have been around all summer, but right now, they are as big as they will get and are moving about looking for mates. We found our first pair on some mountain mint, the diminutive male clasped to the back of a large, fecund female. When I was a kid, we all thought that female praying mantises, like black widows, routinely ate the males after copulation. This isn’t quite true (for either of these species). It is relatively unusual for the female to decapitate and eat the male, largely due to the sneaky courtship (if you can call it that) of the male.
Because the female is so much larger than the male, if he approaches her there is a good chance, she will eat him. Instead, the males follow the female and jump on her back when she isn’t looking. She is unlikely to eat him once this has happened and he will hang out on her back until fertilization is complete. This can take hours. When he is finished, the male will drop off her back, oftentimes waiting until she is preoccupied with something else. After falling to the ground, the male often freezes for a few minutes–perhaps to take a rest, or perhaps to avoid drawing the attention of the hungry female. The adult praying mantises don’t survive our winters, instead the female will eventually produce an egg case-called an ootheca–which contains up to 200 eggs. The ootheca are often attached to the warm and sunny side of a protected wall or fence post. The eggs will hatch in the spring and the young praying mantises will wander our fields, eating whatever they can, eventually growing into the big, beautiful praying mantises stalking our backyards today.
Susan Pike, a researcher and an environmental sciences and biology teacher at Dover High School, welcomes your ideas for future column topics. Send your photos and observations to spike3116@gmail.com. Read more of her Nature News columns online at Seacoastonline.com and pikes-hikes.com, and follow her on Instagram @pikeshikes .
This article originally appeared on Portsmouth Herald: Why praying mantises show up in the fall: Nature News
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