Do males want to be eaten after mating? They go to great lengths to survive

There are some magical phenomena in nature. For example, some female animals will eat male animals after mating. This phenomenon is called "sexual cannibalism."

Sexual cannibalism, to put it simply, is the killing and eating of one's own kind before, after, or during mating.

This behavior is common among arachnids such as black widow spiders, but also exists in insects, gastropods and copepods. Common examples include robber spiders and blue-ringed octopuses.

A common form of sexual cannibalism is female animals eating males, although there are a few cases where females are eaten.

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When it comes to cannibalism, the animal that comes to most people's mind is probably the praying mantis. In "Black Cat Sheriff", the female praying mantis will eat her "husband" on the "wedding night". During mating, the high concentration of pheromones secreted by the hungry female paralyzes the male, and then the female praying mantis will bite off the male's head in one bite. She moves quickly and ruthlessly, as if the male is just a dish to it, no different from other food.

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In addition to mantises, black widows are also typical examples of cannibalism: spiders are typical creatures that eat their own kind, and the most famous of them is the "Black Widow".

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Black widow is a name people gave to this spider because of the characteristic of the female spider eating the male during mating. The scientific name of this spider is red-spotted spider, belonging to the Lycosa family - spider genus, the body is generally black, the male body size is generally between 2-8 cm, it is a tall and strong guy in the spider world, the female has a red hourglass-shaped pattern on the abdomen, this bright red pattern is their unique mark!

Like other spiders, the black widow hunts by "sitting and waiting". After the prey falls into the trap, the black widow will quickly attack, wrap the prey tightly with tough spider silk, pierce the prey with its teeth, and inject venom into the prey's body. After the prey stops struggling, they inject digestive enzymes into the prey's body and enjoy it.

The venom of the black widow contains neurotoxins, which are extremely toxic. A few hours after a person is bitten, the pain intensifies and the wound hardens, accompanied by chills, fever, vomiting and severe abdominal pain. It can also promote the release of the neurotransmitter acetylcholine and cause muscle contraction. Severe bites can be life-threatening.

Black widows have a strong reproductive capacity. The female will slowly eat the male during mating, and store the semen after mating. When the environmental conditions are good, eggs are laid every 25-30 days. The eggs are wrapped in a spherical capsule and hatch in about 12-14 days. They live together. During this period, if there is a lack of food, these small spiders will eat each other.

In addition to spiders, scorpions also eat their own kind. In most scorpion species, female scorpions will eat males during mating. According to statistics, more than half of desert scorpions will prey on their own kind.

Most cases of cannibalism involve females eating males, but researchers have also seen males eat females. Males of a species of spider called Micaria sociabilis eat females. Males have also been observed eating female mates in another spider, Allocosa brasiliensis, and in some crustaceans.

Why does cannibalism occur?

Richard Dawkins popularized the idea in his 1976 book The Selfish Gene that the sole purpose of biological life forms is to pass on their DNA to the next generation.

From this perspective, our bodies may be little more than containers for genetic information, and once these genes are passed on to the next generation, the body has no need to exist.

This view applies to many animals that reproduce only once in their lifetime. Males of salmon and broad-footed marsupials die after reproduction, and some, such as male brown widow spiders, sacrifice themselves to female spiders.

An even more surprising scene is that after mating, the male redback spider somersaults directly into the mouth of the female spider. Moreover, scientists have found that males who sacrifice themselves will have more offspring.

Different from the above view, some scientists believe that in many cases cannibalism stems from basic needs. Pregnant women need a lot of food to provide energy, and when food is scarce, males just provide them with the nearest source of protein.

Of course, not all males are so selfless, and in many species, females behave in a predatory manner.

One theory is that cannibalism is a "maladaptive side effect" of female aggression: Larger, more aggressive females tend to have better hunting abilities, a higher chance of survival and reproduction, and males may be no different from food to them.

In addition, some scholars have proposed that sexual cannibalism is the reason why females become picky. During the courtship period, females will be pursued by many males, and they will make choices and kill the males they don't like. Studies have found that male wolf spiders that are not outstanding are more likely to be eaten.

Males who don't want to be eaten

Do all males want to be killed? No!

If the male mantis does not want to be eaten, he will take a very wise protective measure, that is, he will not actively approach the female, but wait until the female catches other prey and has a full meal before going forward to mate with her. In this way, the female mantis in a full state will most likely not eat her mate.

In order to avoid being eaten, some male spiders will try their best to prevent the female spider from opening her mouth when mating with her to avoid being swallowed. Some smarter ones, such as the robber spider, will bring a long-prepared food to satisfy the female spider's appetite, thereby reducing the risk of being eaten.

Scorpions are even more ruthless. Many male scorpions will sting the female scorpion to unconsciousness before or during mating, making it impossible for the female scorpion to bite them. They really use all means to survive! (They are so scheming)

Some males are also quite scheming. For example, the golden spider chooses to mate with the opposite sex who is molting. This greatly increases the survival rate after mating.

Sexual cannibalism is a behavior that emerged during the process of natural selection. No matter what factors led to the emergence of this behavior, it has its reasons. What do you think?

References:

[1] Qiudao, Shasha. Black widow spider[J]. Global Human Geography, 2015.

[2] Nathaniel Scharping. Sexual Cannibalism: Why Females Sometimes Eat Their Mates After Sex, PLANET EARTH, 2021.

[3] Ren Tian. Male spiders also eat their female mating partners[J]. Science Grand View Garden, 2013(11):1.

[4] Ye Xiaohe. A romantic moment costs one’s life[J]. Environment, 2009, 000(009):76-77.

Review expert: Ran Hao, well-known popular science writer.

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