When praying mantises come together to create a life, it can, for one parent at least, be a risky business (of which more later). It all starts in a seemingly normal fashion, however. First, the female praying mantis exudes a pheromone to let the males around her know she is ready to mate. Drawn in by the whiff of this enticing chemical, the male (which is usually smaller than the female) approaches – albeit cautiously.
In some species, such as the Chinese praying mantis, the courtship ritual is elaborate. In these cases, the male leads the female in a special courtship ‘dance’ designed, perhaps, to get her in the mood for love – rather than for an easy meal.
Uh-oh… She’s turning around
After approaching her, the male is known to quickly leap onto the female’s back, grabbing her thorax and wings using his spiky forelegs. He then deposits his sperm into a small compartment at the end of the female’s abdomen. This mounting process can take a long time – up to 24 hours, according to one observer. No wonder some male mantises die of exhaustion.
There’s nothing like some post-decapitation body fluids when you’re thirsty!
Most people know about the sexual cannibalism often displayed by praying mantises, but why it happens is still a topic of debate. One popular theory says that it’s at least partially our fault. According to researchers, incidences of females killing and eating males during mating happens much more when they are disturbed – not least, by sticky-beak humans.
I’ll take a leg, thanks!
Another theory has it that after having his head bitten off, the male praying mantis is actually better at reproducing. It seems the unfortunate insect might even dispense sperm more energetically once he’s been decapitated, and for longer! Good for his genes; not so good for him.
There’s no escaping this headlock.
Whatever its reason, cannibalism by the female praying mantis doesn’t really happen that often. The rate at which it occurs could apparently be as low as 5 percent, and certainly no more than 31 percent, of the time. Yet, however common it may be, the most notably dangerous time for the male is not during mating, but immediately afterwards as he dismounts. This is when the female is most likely to turn him into a well-earned snack if he’s not careful.
Being pregnant is such a drag.
In the autumn, following mating, the female praying mantis prepares to lay her eggs. She starts eating more food, and her abdomen begins to swell up, making it harder for her to move around. (Human mums to be can certainly empathize!)
Not long now until this lovely speckled mantis becomes a mom
Interestingly, there are some rare species of mantis that don’t need to mate at all to produce young. These species, such as the Brunerria borealis, the stick mantis, can lay viable eggs without fertilization by sperm; however, the nymphs that hatch will all be female clones of the mother.
Preparing the ootheca
When she is ready to lay the eggs, the pregnant mantis finds either a flat surface, twig or a good patch of ground, depending on her species. She then extrudes a foamy substance that later hardens into a protective case, or ‘ootheca’, produced from glands on her abdomen.
An ootheca securely wrapped around a twig
Once the ootheca is ready, the mantis begins laying her eggs – anywhere between 10 and around 400 of them. Each of these eggs is carefully maneuvered into spaces in the ootheca that will help keep them dry, at a nice temperature, and safe from predators until they are ready to hatch. In some species the mother also stands guard.
A close-up look at a foamy ootheca
The size of the ootheca varies considerably from species to species. Some praying mantises lay ootheca only a few millimeters long, while other such casings might measure up to eight centimeters in length. Similarly, the consistency of the casing can be anything from softer and foamy to thick and tough.
It’s wise to stay away from your sibling nymphs if you don’t want to be their first meal.
As the weather warms up, the baby mantises start emerging from their incubating capsules. At this stage in their life cycle, they are called nymphs, and, while not quite as beautiful as the nymphs of Greek myth, they still think they’re rather cute. Sort of.
Only some of these baby mantises will live into adulthood, so for the clutch (the number of hatchlings) it’s a case of survival of the fittest. In order to grow up, the nymphs will need to escape various predators – including their own siblings!
The nymphs descend on their tiny silken threads.
When the tiny nymphs are ready to emerge from the ootheca (usually early in the morning), they crawl out from one-way valves in their compartments. They then hang from tiny threads like cobwebs a couple of inches below the case.
Not all babies are cute…
After hatching, it only takes about one or two hours for the praying mantis babies to disperse. Even when they are young, mantises are master camouflage artists. Indeed, at this size their appearance often mimics that of ants, making them hard to spot.
A young nymph stops to smell the roses.
The praying mantis nymphs often look just like their parents, except that they lack wings and reproductive organs and, of course, are much smaller. Initially they might be a different color to adult praying mantises as well, but this soon changes.
I look just like my dad!
While the nymphs are so tiny, they can only hunt similarly sized prey. Usually this means insects such as fruit flies, aphids, or – as mentioned earlier – each other. As they grow, they will hone their hunting skills, and soon enough they’ll be able to prey on insects (and other creatures) even larger than themselves.
It’s hard to stay out of the spotlight when you’re this cute.
Young praying mantises grow quickly, and can be several inches long by the end of the summer season. As their size increases, so does their food intake: an adult praying mantis can eat up to 25 flies in a single day! Their voracious appetites make them popular with gardeners, who sometimes use them as an organic form of pest control.
An aptly named orchid mantis molts.
As a praying mantis grows into a full-sized adult, it needs to shed its exoskeleton (or molt) several times over. This can happen between five and ten times, and it is during the molting process that the mantis is at its most vulnerable to predators: shedding the exoskeleton can take a few hours, meaning the creature is unable to defend itself or make a quick getaway.
This would not be a good time to be spotted by a hungry bird.
Just before molting, a praying mantis becomes lethargic and stops eating. It finds a sturdy spot on which to anchor itself and begins to molt. It is a tricky process, and some unfortunate mantises don’t make it, getting stuck in their old exoskeletons until they die.
A discarded exoskeleton looking a little like an alien space suit
It is after molting for the last time that the young mantis finally gets its wings – unless of course it belongs to a (rare) wingless species. Once it has these, it can now be said to be a fully mature praying mantis.
A grown-up praying mantis is a formidable carnivore. It either tenaciously stalks its prey or simply waits to ambush it – often aided by its cunningly camouflaged body. Different species of praying mantis can be mistaken for leaves, sticks or even flowers. And once it has its victim in those spiny forelegs, well, let’s just say it’s usually a woefully one-way battle…
The life cycle of the praying mantis is short: only about a year in the wild and a little longer in captivity. What they lack in time, however, they make up for in variation – not to mention a certain macabre appeal. They certainly are amazing little creatures!