In some spider species, the mating process is accompanied by highly risky and unusual behaviors. For example, for male spiders of the species Herennia multipuncta, mating can sometimes be life-threatening. The main reason is that female spiders are several times larger than males and, in some cases, may consume the male after mating.
However, the most interesting and unusual behavior observed in this species does not end there. These spiders, also known as “coin spiders,” partially or completely tear off and chew their own reproductive organs—known as palps, which are used to transfer sperm—during or after mating.
The phenomenon of self-amputation
Scientists describe this behavior as “self-amputation.” This phenomenon has been observed in at least more than ten spider species.
Observations show that:
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some males lose their palps before reaching full maturity
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some do this during mating
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others abandon these organs after mating
The fact that this behavior occurs at different stages suggests that it provides certain evolutionary advantages.
What do scientific studies say?
Scientist Matjaž Kuntner from the Slovenian Academy of Sciences and Arts, together with his colleagues, conducted extensive research to understand the reasons behind this behavior. The results were published in the journal Behavioral Ecology and Sociobiology.
Within the scope of the study:
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spiders collected from Southeast Asia were observed under laboratory conditions
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60 mating experiments were conducted
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only half of them were successful
During successful matings:
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9 males lost only one palp
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23 males lost both palps
Interestingly, females did not immediately consume the males. However, within 24 hours, the males themselves chewed off and removed their remaining palps.
What is the purpose of this behavior?
According to the main hypothesis, the loss of palps creates a physical “barrier” within the female’s reproductive organ. This makes it difficult for other males to mate with the same female.
Experiments have shown that:
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previously mated females may still allow another mating attempt
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however, new males are unable to insert their palps
This gives the first male a genetic advantage.
Other possible explanations
Researchers also suggest that this behavior may provide additional advantages:
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males that lose their palps become lighter and more agile
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this helps them behave more aggressively and endure longer
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as a result, they gain an advantage in competition with other males
Alternatively, this behavior may be an evolutionary remnant from the past. In other words, males may have developed this strategy to protect the female and reduce the chances of rival males.
Conclusion
The unusual behavior observed in Herennia multipuncta and similar spider species demonstrates how complex and fascinating evolutionary mechanisms in nature can be.
At first glance, the act of sacrificing their own reproductive organs may seem strange or even “absurd,” but in reality, it is a strategic behavior aimed at increasing reproductive success.
This once again proves that even the strangest behaviors in nature have underlying logic and evolutionary advantages.