Death by sex

Having talked a lot about animal sex recently, I felt it important to tip my hat to some of those creatures out there that really have the sex of their lives… Forget chocolate, these animals die because of sex, often just after copulation but even midway through the ‘romantic’ act…

How to make love to a cannibal?  Carefully.  The most touted example of cannibalistic love is the praying mantis, a species well known for females eating males after sex.  But they often go one step further and eat their mate during the act… This might seem counter-intuitive but in doing so, they get their eggs fertilised and have more fun.  Obviously the male is a bit scared and tentative as they approach and assume the position, not the best attributes for a good romp…  If however, you bite off their head… the male’s body goes into spasms which allow for sperm to be delivered and the joys of vibrations.

“Females in more than eighty other species have been caught eating their lovers before, during, or after sex.  Spiders are the most common culprits, although several other mantises, some scorpions, and certain midges also number among the guilty.”
– Olivia Judson

For orb-weaving spiders, pheromones play a key role in the male’s willingness to be cannibalised by his mate…

“When exposed to mated females, males attempt to escape much more often than those exposed to virgins.  The latter show a tendency to self-sacrifice in the name of biological fitness.”
– Carin Bondar

The combination of sex and cannibalism is attractive to some females because not only can they get their eggs fertilised but they can also have a great, nutritious meal, perfect for keeping the mum to be healthy.  To avoid death, some species of spiders which practice sexual cannibalism, males have evolved to break off their genitalia, thus plugging up the female in the hopes that it will be their sperm used in fertilising eggs.

Similarly, when male honeybees climax, their genitals are ripped from their body – the idea is that leaving behind your genitals in the queen prevents other males from mating with her and thus ensures her young are yours.  Obviously once the genitalia has been forcefully ripped from the males, they die.

It’s a big of a grey area in terms of death but in some species, the males commit themselves so much to the task of mating that they lose a sense of  themselves.  Take for example the angler fish, the males are much smaller than the females and they search the seas for a mate.  Once a female has been found, they will bite into her underbelly and fuse themselves to her permanently.

In some species, it’s the males that get carried away and kill or severely injure the females…  A flock of sheep on Ile Longue have been left to their own devices and the result is that ewes are chased and battered by the rams.  Once pinned down the males try to mount her repeatedly for hours.  If she’s lucky and the injuries and exhaustion haven’t killed her, she risks being disembowelled by giant petrels…

For some frog species, sex is a bit of an orgy.  Females gather in pools to mate, they release eggs into the water and the males squirt in their sperm.  If a female has attracted several males, they all push and shove so its their sperm that get to fertilise the eggs.  As they do so, there is a risk that the female drowns or is crushed.  A similar situation arises for some solitary bees and wasps; when the females emerge from their burrows, they are greeted by a hoard of males, all desperate to mate and in that desperation, she may end up dead.

In the rough sex gone wrong category, we can also find southern elephant seals who may end up killing their lovers by biting females on the head instead of the neck and dog mink who pierce the base of the brain instead of grabbing the scruff of the neck.

There is also the salmon, where both males and females die shortly after scattering their eggs and sperm to the rivers.  This strategy of using up all your energy and resources is called semalparity, or suicidal reproduction and is also practised by the antechinus.  The males of this species engage in an active sex frenzy for about 14 hours, and in doing so destroy their immune systems.  After mating, a lot, they suffer from internal bleeding, collapse and die.

Basically, life is tough, and sex can be tougher…  Next up I’ll be looking at parenting in the natural world; do dads play a role? who has it hardest? who engages in infantcide?

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