Why Do Mantis Eat Their Mates?

Praying mantis for famous for getting eaten while reproducing – but why do mantis eat their mates?

The Surprising Benefits of Getting Eaten

Why do female praying mantids often eat the males?

When viewed through the lense of humans, getting eaten by your mate seems like a pretty barbaric practise. I mean, imagine how you’d feel if your mom ate your dad! 

For insects, however, the rules of the game can be very different. What we think of as odd is perfectly natural – and eating your mate may actually make a lot of sense. 

Praying mantis tend to have very short lifespans, with many hatching in the spring, before laying eggs and dying just a few months later.

This means they need to eat as much as possible so they can grow rapidly and complete their lifecycle in time. 

However the food supply doesn’t just affect how quickly they grow: it can also impact how many eggs the females lay. 

A female mantis that eats her mate may therefore be bulking up on calories so she can lay as many eggs as possible. This can also benefit the male as he ensures that he ends up with as many young as possible, passing his genes on to the next generation. 

Do Mantis Keep Mating While the Male Mantis Is Being Eaten?

I have observed the “sexual cannibalism” of praying mantis numerous times both in the wild and in pet mantids. Generally the mantis will keep on mating even while the male is being devoured.

It seems that the head of the male mantis is most appealing to the female. The remainder of the male’s body can remain in situ for the full mating ritual – which can take some hours. 

Once the mating is finished the female may then finish off the rest of the male, or more likely his long-dead body will simply drop to the ground to decompose.

Do All Males Get Eaten After Mating?

If you listen to the urban legends then could be mistaken for thinking that male praying mantis always get eaten when mating. However, this isn’t necessarily the case.

Some studies in the European mantis suggest that the male survives in roughly three quarters of cases.

While these figures have not been calculated in other mantis species to my knowledge, we can say conclusively that at least some males survive mating.

Do Praying Mantis Eat Their Babies?

Praying mantis are carnivores that will eat anything small enough for them to catch. This means that, at least in theory, a praying will indeed eat their babies given the option.

That said, many mantis egg cases (also known as oothecae) hatch some months after being laid, by which time their parents have long since died of old age. 

As this generational crossover is unlikely in many species, praying mantis often don’t get to eat their babies, even if they wanted to. 

How Do I Prevent My Pet Praying Mantis From Eating Its Mate?

If you want to breed praying mantis at home then a major concern is keeping your male alive. This is especially important if you only have a single male, but multiple females you want to put him with. 

While there is no guaranteed method of keeping a male praying mantis alive during mating there are three tips that I have found to be quite effective over the years…

Feed Up the Female

The first tip is to feed your female praying mantis as much food as she can possibly eat in the weeks leading up to mating. You want her feeling so stuffed that just the idea of eating your poor male is enough to make her feel ill 😉

Provide Food Before Mating

Once the female has been fattened up it’s time for the introduction. I’ve had some success here giving the female a final juicy insect to eat, waiting until she’s actually started eating, and then introducing the male. She’s often so busy eating that she doesn’t notice the male approaching so he gets off lightly.

Ensure Space to Escape

Lastly, praying mantis can take a surprisingly long time to mate. They may well be going for hours on end. You might be waiting a full day till everything is finished. It’s therefore unreasonable to sit there all that time waiting to rescue the male. 

Instead I like to ensure there’s plenty of space in the cage, so the male can quickly escape at the end, and avoid the female until I remove him. 

I then keep an occasional eye on the cage, and as soon as I notice that they have separated the male is carefully removed.

Richard Adams

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