Many people may be surprised that praying mantis will eat their mates!
In fact, this phenomenon is called sexual eating, which is more common in nature, in addition to praying mantises, some spiders (such as black widows) and many insects will appear in this behavior, even some snakes will do this.
In most cases of sexual eating, most of them are dominated by females, in other words, most females eat males, typical cases are praying mantis and black widow spiders. But a few are also male-dominant, such as a South American cave-dwelling tarantula, scientific name Allocosa brasiliensis, males will "sex-eat" females.
Many people think that male praying mantis is eaten by female praying mantis in order to pass on their genes to resources and dedication, but in fact, the reasons for sexual eating are complex and interesting, and I summarize the following reasons:
Photo by Phil Hastings
Sheer hungry
Sexual eating of the same kind, not only occurs during and after mating, but also before mating.
Scientists have done relevant experiments on praying mantises, the first time is to feed female praying mantis and mate, and the results are that the male mantis after mating is not eaten.
The second experiment was to divide the female mantis into three batches, respectively starved for 5-11 days, 3-5 days, and 0 days (full), and the results showed that the most hungry batch, did not want to reproduce the next generation at all, came up and ate the male praying mantis; The batch that has been hungry for three or five days is to mate first, and then think about eating male praying mantises; The group that was not hungry at all, as in the first experiment, did not eat a mate.
It can be seen that for praying mantises, the biggest reason for eating or not eating a mate is hunger.
Female praying mantis ©CaPro
I'm big, I'm reasonable
Generally speaking, animals that are obviously aggressive to the same kind and have obvious body size differences between males and females are prone to sexual cannibalism.
Just like praying mantises, female praying mantis is obviously larger and stronger than male mantis, and has the ability to eat its own kind.
If a female mantis itself has a bad temper and is very aggressive, when it encounters a male mantis, if the male mantis courtship ritual is not perfect, or some other reason provokes the female mantis, it will take an attack to refuse the male mantis's mating invitation.
Male and female praying mantis compared to ©Oliver Koemmerling
Can't look at it
For mate selection, animals also have their own choice, when they choose a mate, mainly from the aspects of body size, aggression, appearance, etc., courtship rituals are also key, and the various movements and dances in it are also ways to show whether the individual is healthy.
In general, large, aggressive individuals are considered healthy, genetically superior, and more favored by courtship animals.
Allocosa brasiliensis, mentioned at the beginning, is picky about its mates, and scientists have found that the animal often cannibalizes older females.
Unlike most sexually eating animals, this tarantula is a "husband eats a wife". When courting, it is also the other way around, the male emits pheromones to attract the female, and when the female is attracted to meet, the male will first assess the overall situation of the female.
Of course, the purpose of the assessment is to determine whether the female who comes to meet is suitable for mate or food!
In Allocosa brasiliensis, older females have a lower reproductive potential and, on balance, are more likely to use the older opposite sex as food.
The same is true in praying mantises, where at first the female mantis is very aggressive towards male mantises, and the purpose is also to test the health of male mantises. If the male mantis is easily defeated, it will be considered that the food advantage is significantly greater than the genetic advantage, and it will naturally become the food of the female mantis.
Voluntary sacrifice in order to pass on the genes
In nature, many animals exist just to reproduce and have no self.
The more impressive is the male catfish, which is a deep-sea fish with a "small lantern" on its head, and its appearance is difficult to say. It has many peculiarities, and I think the most peculiar is its "view of marriage".
Females and males vary greatly, with females as large as 1 meter and males up to a dozen centimeters (single-digit 2 centimeters have also been found). The combination of the two is also unique, after the male finds the object of his choice, he bites the female and then slowly merges with the female body and becomes a part of it. Next, the male's body degenerates except for the reproductive organs.
Simply put, the male has no self at all, it is at best a reproductive organ (real gene container) on the female's body, and the rest is completely dependent on the female to live.
Pictured: Male salmon typically eat soft rice
In similar cases of sexual eating, many male animals are relatively weak in themselves, and even if they do not mate, most of them will die unexpectedly. So in order to pass on genetic material, they will do whatever it takes.
When scientists were studying red-backed spiders, they found that the existing male red-backed spiders not only did not run away when mating, but even took the initiative to sacrifice their abdomen and issue an invitation: "Come, eat!" ”
The main reason for this is to extend the time of pairing, the female spider accepts the male spider's invitation, after starting to eat, will not immediately go to other males, and the male spider also has more time to complete the entire fertilization process, and it must leave much more offspring than male spiders who did not voluntarily dedicate themselves (the study results are 40% more).
At last
Animals are animals after all and cannot be analyzed from a human perspective.
Most animals have no mate, parent, or family concept, and their lifelong goal is to survive and reproduce. Animals have always been king, and larger and stronger animals have the ability to decide other lives and deaths.
For female praying mantises, eat when hungry, whether it is the same kind, whether it is a mate It will not pay attention;
For male praying mantises, most of them are not eaten voluntarily, and when it is balancing survival and reproduction, it is not very lucky, and it picks a strong mate, which cannot escape being eaten, and can be said to be eliminated by nature.