Why Do Female Mantises Eat Their Mates?
42sThe shocking act of sexual cannibalism is instantly attention-grabbing and sparks curiosity.
▶ Play ClipAI Summary
This video explores the phenomenon of sexual cannibalism, where females eat males before, during, or after mating. It explains the evolutionary reasons behind this behavior in species like praying mantises and redback spiders, highlighting how it can benefit both sexes under certain conditions.
Chapters
[00:00]
Sexual cannibalism introduction
Female praying mantises sometimes eat the male's head during mating. This behavior is called sexual cannibalism and occurs in many species, almost always with the female eating the male.
[00:42]
Why females eat males
Since females lay eggs or nurture offspring, males eating females would be detrimental to reproduction. In species where males don't help raise young, the female benefits from consuming a protein-rich mate to support egg production.
[01:27]
Evidence from mantises
A study found that female mantises that ate their mates laid more than twice as many eggs as those that didn't, suggesting a direct reproductive benefit.
[01:54]
Male self-sacrifice in redback spiders
Male redback spiders somersault into the female's mouth after mating, sacrificing themselves. This may have evolved because most males die before mating, so self-sacrifice ensures offspring are well-provided.
[02:22]
Pre-mating cannibalism
Sometimes females eat potential mates before mating, which seems counterproductive. This can occur due to high female aggression that accidentally targets males.
Sexual cannibalism, while seemingly extreme, often provides evolutionary advantages such as increased egg production or ensuring male genes are passed on when mating opportunities are scarce.
Mentioned in this Video
Study Flashcards (5)
What is sexual cannibalism?
easy
Click to reveal answer
What is sexual cannibalism?
easy
Click to reveal answer
When an animal eats its mate or potential mate before, during, or after mating.
00:27
Why do females usually eat males rather than vice versa?
medium
Click to reveal answer
Why do females usually eat males rather than vice versa?
medium
Click to reveal answer
Females lay eggs or nurture offspring; if males ate females, they would reduce their own reproductive success.
00:42
How much more did mantis females that ate mates lay eggs?
easy
Click to reveal answer
How much more did mantis females that ate mates lay eggs?
easy
Click to reveal answer
More than twice as many eggs.
01:27
What do male redback spiders do after mating?
medium
Click to reveal answer
What do male redback spiders do after mating?
medium
Click to reveal answer
They somersault into the female's mouth to be eaten.
01:54
Why might male redback spiders sacrifice themselves?
medium
Click to reveal answer
Why might male redback spiders sacrifice themselves?
medium
Click to reveal answer
Because most males die before mating, so self-sacrifice ensures their offspring are well-provided.
02:10
💡 Key Takeaways
📊
Mantis egg production boost
Provides quantitative evidence of the reproductive benefit of cannibalism.
01:27
⚖️
Redback spider self-sacrifice
Illustrates an extreme evolutionary adaptation where males actively participate in their own consumption.
01:54Full Transcript
[00:00] In the middle of baby-making, a female praying mantis will sometimes chomp down on a male’s head, then devour him as she finishes mating with him. And mantises aren’t alone; many different species lunch on their lovers.
[00:13] it’s almost always the females doing the eating. Why is it dudes that always end up as dinner? [Kate:] Oh, sorry! This is MinuteEarth.
[00:27] All sorts of critters will occasionally munch on members of their own species, but here, we’re talking specifically about when an animal eats its mate – or potential mate – before, during, or right after babymaking, which scientists call “sexual cannibalism”.
[00:42] And – think about it – since females are the sex that lays the eggs or nurtures the offspring inside their own bodies, if a male eats a female before, during, So any male who regularly dined on his dates wouldn’t be able to pass along the habit.
[00:59] habit of lunching on their lovers – and sometimes, that habit really pays off. raise the babies doesn’t make a lot of sense.
[01:12] But in species where males don’t help out, the female gets left alone to raise the babies – sometimes a LOT of babies – which takes a lot of energy. So if a convenient, protein-packed snack is, like, RIGHT THERE, it benefits her bigtime to chow down.
[01:27] One study found that mantis females that ate their mates laid more than twice as many eggs as those that didn’t. Which might make it seem like mate-eating helps both female AND male mantises leave behind a bigger genetic legacy.
[01:40] But since the male ends up dead, his future prospects are over; if he hadn't been eaten, he could have gone on to mate again – and again, leaving way more babies behind. In some cases, though, getting eaten does seem to benefit males.
[01:54] After redback spiders mate, the male often somersaults into the Scientists think this self-sacrifice evolved because in this species, the vast majority of males get eaten by predators before they ever get a chance to mate.
[02:10] So if a male redback does get lucky enough to actually get lucky, he might as well sacrifice himself to his mate to make sure the babies are well-provided for.
[02:22] So we've covered why males get eaten during and after babymaking, but what’s up with eating a potential partner before mating, which guarantees exactly zero offspring from the pair-up? competition is intense, so it really pays for females to be super aggressive,
[02:41] and all that innate aggression can accidentally end up directed toward a potential mate...oops! The bottom line is that, while it seems unthinkable to us, sometimes it does make sense for females to plate their dates.
[02:58] uncomfortable – it quietly shapes a lot of decisions we make every day. face a moment when a job no longer feels stable, meaningful, or flexible enough.
[03:10] – an online tech bootcamp built for people who are starting from scratch. What I like about them is that you don’t just study and disappear into the job market alone:
[03:22] TripleTen gives you unlimited externship projects even after 82% of TripleTen’s grads get hired in 6 months or less. Click the link in the description or scan the QR code now for your
[03:37] free career consultation with TripleTen – let’s make your future freedom-friendly. Thanks, TripleTen!
