Childhood Shadow: Did the male praying mantis in "Black Cat Sheriff" really want to be eaten?

Produced by: Science Popularization China

Produced by: Su Chengyu

Producer: Computer Network Information Center, Chinese Academy of Sciences

Talking about the childhood shadow series, those who have watched "Black Cat Sheriff" must remember this scene: in the cartoon, on the wedding night, the bride mantis ate her husband, leaving only the remains on the ground.

Image source: Black Cat Sheriff eats her husband's mantis

In the second half of this episode, the bride mantis explains why she eats her husband: she eats him because she loves him. The groom also volunteered to be eaten so that they could give birth to healthy mantis babies. He did not resist and even wrote a suicide note. After hearing this explanation, Sheriff Black Cat announced that the bride mantis was not guilty and everyone was happy.

After watching the cartoon, we know that the female mantis needs nutrition when she is pregnant, and the husband who is closest to her becomes the most convenient nutrition.

Image source: Black Cat Sheriff eats her husband's mantis

Do male praying mantises always do so “without complaint” when being eaten?

In fact, long before "Black Cat Sheriff", and even before modern science, humans had observed and recorded the phenomenon of praying mantises cannibalizing their mates during mating. Coupled with the lack of scientific explanation, religious superstition, and anthropomorphic descriptions of animals, the words "praying mantis' wedding" and "blood" have always been tied together.

This phenomenon is described in the world-famous book "The Insect World" and has been widely circulated. In the writings of French entomologist Fabre, even if the female mantis's lover is bitten into pieces, she still spares no effort to continue her unfinished work until she is eaten bite by bite without any resistance. In Fabre's view, this is the result of marriage customs, and the male should not have any complaints about it.

Male mantis having its head eaten by a female mantis Source: mentalfloss

But in reality, do all male mantises not resist before being eaten?

The answer is no.

As early as the 1930s, insect neurophysiologist Ken Roader conducted experiments and observations on the sexual behavior of mantises.

Image source: the biological bulletin

He observed that it was not common for female mantises to eat mantises before or after mating, and only occurred under specific circumstances.

For example, if they are kept together before mating, the male mantis will basically have no way to escape and will be eaten. For another example, if the male mantis is stupid and mates from the front, and does not know how to sneak up from behind and finally climb on the back of the female, he will also be eaten. For another example, if the male mantis's sudden action before mating angers the female mantis, he will also be eaten...

Ken observed the female mantis eating the male mantis. Source: Reference 1

Ken Roader's experiment actually shows that cannibalism is not a common practice for female mantises. But others seem to have only seen his description of the phenomenon of female mantises eating male mantises, and have not learned much about the conditions behind this phenomenon, which further reinforces the belief that mantises must eat males when mating. Isn't it ironic...

Why do female praying mantises eat male praying mantises?

By the mid-20th century, more scientific experiments on mantises further confirmed that cannibalism was not common. Two scientists raised Chinese mantis eggs into mantises and then observed their mating under different conditions.

A battle between male mantises for survival

Scientists controlled the feeding conditions of mantises and divided them into three groups: some mantises were well fed before being attracted to each other, some were starved for 5 to 11 days before mating, and some were starved for 3 to 5 days. Scientists observed a total of 69 matings.

It was observed that among the mantises that had been hungry for 3 to 5 days, only once did the female mantis bite off the head of the male mantis before mating. Among the other 7 very hungry female mantises, 6 attacked the male mantis, and their purpose was simply to eat each other, and they had no intention of mating at all. Among these mantises, sometimes the male mantis successfully avoided the attack, and then forced mating and was not eaten. Other female mantises that were particularly hungry either ate the male mantis as a meal before mating, or ate it as a meal after mating. As for the remaining group, those female mantises that were full before attracting each other had no intention of eating the male mantis at all.

It should be noted that even though the phenomenon of eating occurred in the experiment, under natural conditions, male mantises are unlikely to be eaten. Because in the experiment, the mantises were locked together from beginning to end, and the male mantises had no way to escape. Under natural conditions, male mantises would only appear quietly when they need to mate, and then quietly run away after mating. Why would they stay in the same cage with female mantises and wait to be eaten...

This study shows that female mantises only eat male mantises when they are hungry. Their purpose is not to reproduce better, but they are just hungry and want to eat. In addition, in this process, male mantises will try to escape in order to survive. For mantises, love is more important than life, and there is no such thing as voluntarily sacrificing themselves to supplement nutrition for their spouses and reproduce better offspring.

A battle between male mantises for survival

The above studies only show that female mantises will eat male mantises under certain circumstances. But the following research result is even more shocking: male mantises will fight with female mantises in order to survive!

Researchers from the University of Auckland in New Zealand collected both male and female Springbok mantises from across Auckland and placed a pair of males and females in an inverted plastic cup to see what would happen.

As a result, they found that during the whole process, the male mantis did not sit and wait for death, curled up in a corner and waited to be eaten, but fought back and wrestled with each other, raising their respective "scythes" to grab each other. Most of the battles lasted about 12.77 seconds, and the victory or defeat determined the life or death of the male.

A female and a male mantis fighting each other. The yellow one is female, and the green one is male. Source: Document 2

So the question is, does the female always win the fight and the male just struggles in vain? This is not the case.

In this battle between male and female mantises, 7% of the fights ended in a draw, 35% of the fights were won by the female, and 58% of the fights were won by the male.

When the females failed, they were sometimes seriously injured. In some cases, the male's front paws pierced the female's abdomen, leaving only bloody wounds.

The wound of the female mantis has scarred. Source: Document 2

However, for males, victory does not always mean survival. There are three outcomes when the male wins: either he successfully subdues the other and completes mating, or he is eaten and does not mate, or they break up peacefully. In short, it doesn’t matter if you win, I may still eat you.

In any case, the male Springbok mantis should be considered the best among the existing male mantis species. At least he dares to confront the female head-on. The others can only live in misery and quietly look for opportunities to mate.

Researchers believe that the reason why male Springbok mantises dare to fight is mainly because the body size difference between males and females is not much.

The two fighting each other below, the yellow one is a female mantis, and the green one is a female mantis, which is just a little bigger.

Image source: Document 2

If you look at the other mantises, the one on top that sneaked up to mate is the male, and the one below that looks several times bigger than it is the female. The size of these two mantises is very different.

Image source: youtube

So, in "Black Cat Sheriff", the male mantis said to the female mantis with a loving face, "Dear, if you love me, please eat me after we get married!" This situation is impossible to happen in reality. The male mantis must not be willing to be eaten, but is "forced to do business." Sure enough, sacrificing one's life for love, this kind of thing only exists in fairy tales.

References:

ROEDER, KD (1935). AN EXPERIMENTAL ANALYSIS OF THE SEXUAL BEHAVIOR OF THE PRAYING MANTIS (MANTIS RELIGIOSA L.). The Biological Bulletin, 69(2), 203–220. doi:10.2307/1537420

https://royalsocietypublishing.org/doi/10.1098/rsbl.2020.0811

Fabre's Insects

[1] Dai Bin. Is the life of male mantises in danger during mating? [J]. Biology Teaching, 2001, 26(2):38-38.