Do Praying Mantis Eat Their Mate?

The female praying mantis will cold-bloodedly eat the male after mating. Even worse, she might just bite his head off mid-intercourse. And the male will keep performing the act even without the head! 

You must have heard at least some of these stories if you are interested in mantids at all. But are they really true? Does the female mantis really eat its mate or is it just a myth?

Well, the answer is, yes, female mantis can eat their mates – but it doesn’t happen all the time. 

But what’s the point of eating the partner? Are female mantis simply pure evil or is there some other motive behind the act? And why do they do it only in some cases? Keep reading if you want to find out! 

Sexual Cannibalism in Praying Mantis 

The story of a female praying mantis eating the male after mating is probably the most often mentioned fact about mantids. You’ve probably heard this story already, or perhaps even seen it happen in a documentary.

But do female praying mantis eat their mates all the time? Well, you might be surprised, but it happens less frequently than one would expect.

According to some estimates, the mating ends in death for the praying mantis male only in about 16% of cases. 

So what’s that all about? Let’s start by considering the broader phenomenon of sexual cannibalism. Sexual cannibalism is a known phenomenon in the world of insects and animals that is not limited to the praying mantis.

It also happens among some other species where it’s perhaps more surprising, such as some spiders, crustaceans, and even snakes. 

The phenomenon involves, as you might suspect, eating the partner after mating. Yes, it’s usually the female that performs the act of eating the partner. In some rare cases, it could also be the male. 

Does the Female Mantis Bite the Head Off Its Mate? 

Another notorious story about praying mantis is that the females tend to bite the head off the male. Is this true or just a myth, you might wonder.

Well, it does happen sometimes, although the female mantis is more likely to munch the headpiece by piece due to the shape of her mouth than to bite it off. Still, it could happen in some cases. 

This opens up another interesting topic. Does the female eat the male during or after the mating? Well, both can happen, and sometimes it even happens before the mating even occurs.

In that case, the mantis guy is out of luck, obviously. Sometimes the female starts munching on its mate during copulation, and in such cases, she usually starts with the head.

The amazing thing is that the male can finish the act even without the head. So the female mantis gets a snack and the babies. Still, when sexual cannibalism does happen, it is most often after the act of mating. 

Why Do Praying Mantis Sometimes Eat Their Mate? 

So far we have established that female mantis do eat their mates, but only sometimes. So why does a mantis lady sometimes decide it’s time to munch on her husband?

What is it, exactly, that flips the switch? Well, there are a couple of things to consider: 

Not All Mantis Species Are Equally Aggressive 

While it is true that any kind of mantis might engage in sexual cannibalism, some species are more aggressive than others. Some species of mantis are known to be ‘communal’, like the Ghost Mantis, the Orchid Mantis, or the Wandering Violin Mantis.

Now, no mantis species is truly communal – all of them can engage in cannibalism in exceptional cases – these species do tend to act more peacefully. Multiple individuals can cohabitate and will rarely fight even after mating. 

But this does not hold true for all mantis species. The most common mantis, like the Chinese Mantis or the European mantis, are known to eat their partners when the conditions are right. The Budwing Mantis is often titled the most aggressive mantis. 

A Hungry Mantis Is Not Picky 

Some mantis species are more likely to eat their mate than others, but this still doesn’t explain the question – why would a specific mantis individual eat the mate in some cases, but not every time.

Well, one of the important factors is actually hunger. Namely, a hungry mantis will most likely eat anything it can get. 

Mantis don’t feed that often. It depends on the species, but when food is available they will only eat from once a day to once every couple of days.

A mantis can typically survive about 2 weeks without eating, but the longer it goes without food the more aggressive it will get. Research has shown that a well-fed female mantis is much less likely to eat the male.

A hungry mantis, on the other hand, will not only eat the male when mating, but it might also attack a member of its own species even when it has nothing to do with love. It’s all about survival. 

Moreover, many mantis species mate in autumn, the time of year when food is more scarce. This goes to support the hypothesis that female mantis eat the male when mating simply because they are hungry. 

Size Matters 

Praying mantis typically look for prey that is the right size. If you decide to keep a praying mantis as a pet, you will quickly learn that they need to be fed insects of the right size.

Baby praying mantis will enjoy munching on fruit flies, but as they get bigger, they like to have something larger for lunch too.

Still, a mantis prefers to devour its prey whole so they wouldn’t normally go for something bigger than themselves – except in cases of extreme hunger.

Why is this relevant to our question today? Well, because male praying mantis are typically much smaller than their female counterparts. Basically, they are the perfect size for eating.

So, if the male mantis is of appropriate size (that is, quite large but smaller than the female), the female will be more likely to munch on the male.

Could this be a coincidence? Perhaps, but it’s far more likely that praying mantis have evolved in such a way that the male fits the description of a perfect meal for the female. 

The Adaptive Suicide Hypotesis 

The “why” questions, in biology and otherwise, usually call for complex answers. The question of why praying mantis sometimes practice sexual cannibalism can be answered in many different ways.

Scientists have come up with a variety of different hypothesis as to why mantids have evolved this trait, but perhaps the most interesting is the adaptive suicide hypothesis. 

This theory basically says that being eaten by the female is actually good for the male mantis, at least in the context of evolution.

Survival of the fittest is the basic principle of natural selection, but in the case of the male praying mantis, we should perhaps not take that literally.

Namely, if the male gets eaten during or after mating by the female, their offspring tends to be healthier. This study, for example, has shown that Chinese Mantis females that have feasted on their eggs laid more eggs afterwards.

Moreover, it seems that eating the male not only leads to more eggs, but the babies tend to be healthier as they receive valuable nutrition from the body of the male via their mother.

In short, it seems that getting eaten has benefits for the male in the long run. 

Can the Male Fight Back? 

The relationship between two praying mantis is anything but simple, and it’s not all lovey-dovey either (you probably get the picture already). Praying mantis don’t even live as couples.

They spend most of their life solitary and usually only come together for mating. Sometimes, it can appear as if the male mantis is offering himself to be eaten. But some female mantis will try to struggle and fight to survive. 

One of the most common mating tactics for the male mantis is approaching the female from behind and grabbing her before she can escape.

If the male is skillful enough, he might even be able to escape, even if the female wants to eat him. 

But one particular recent study offers surprising insight into mantis mating rituals. Nathan Burke and Gregory Halowell, the authors of the study, observed the behavior of the Springbok Mantis before mating.

What they found is that the males sometimes proactively decide to fight the females. In these fights, each mantis would try to strike the other with its forearms.

The mantis fights are fascinating, but what happened after is even more interesting. It seems that the outcome of the fight depended on who managed to strike first.

If it was the male, the couple would end up mating. If it was the female who won the fight, she would just eat the male – no mating involved. 

Alright, that’s it for this article, here are a few hand-selected articles that you might also find interesting reads:

Can You Keep Praying Mantis Together?

What do Praying Mantis’ Eat? A Complete Guide

Longest Living Mantis Species -An Examination