Sometimes a guy has to eat, too...

So, you remember when I told you about the benefits of eating your boyfriend? Yes, I know, it has been a while... Sorry about that but I'll try to freak you out more regularly again!

Now you may think that it makes little sense to eat your girlfriend - she is supposed to bear your offspring after all. And that is true - for us mammals. After all she may lay eggs and when those are fertilized and you are willing to take care of the kids, she may be just the snack you've been looking for! At least that must be what the marine worm Neanthes acuminata thinks. This is not the most sociable beast on this planet anyway, as males and females alike can be quite aggressive against same sex individuals of their own species and males also tend to eat the eggs of other fathers - at least if they had had a clutch of their own before. If they are virgin guys they guard strangers' eggs as they would their own - a little training as a future daddy might be a good idea.
But what if they find a mate? Well when a male has attracted a mate she lays her eggs and he fertilized them. Then she dies. And it would be a waste to just let her rot, right? Actually she's even tastier right after the action and he needs the energy to take care of the eggs anyway - and that's when eating your girlfriend actually does make kind of sense. So the next time someone asks you to babysit their kids... just ask for a pizza, okay?
Oh, but if you think that Neanthes acuminata are just stupid, passive victims, that isn't really the case as researchers have found that they actively seek males that are experienced fathers, only mating with virgin males and choosing based on successful fighting when no fathers are around. So if you are a girl and suspect all possible mates to be cannibals, at least chose one that did it before. No, wait, that might not be a good thing. Maybe better just run...

Ouch... just ouch! (The not so happy world of traumatic insemination)

Well, last time things went rather nice, so let's skip plain naughty this time and go for nasty! We already learned that girls can be really nasty but of course, guys aren't much better. Well, at least they usually have to keep their partner alive to reproduce but you know guys - some just want to put their penis into every hole they find. And some are even willing to make new holes - welcome to the not so happy world of traumatic insemination!

Okay, you're still here? Well, you have been warned...

Let's start with silkworms. These are actually kind of cute critters, looking a bit like earthworms with lots of stubby legs and two antennas. And their mating begins innocuously enough as the male attaches his spermatophores, packages of sperm, to his mate's back. But then it gets ugly as the spermatophores dissolve her skin and let the sperm seek their way to her ovaries through her body. Females that have mated several times look like the victim of a shotgun attack afterwards...
But it gets worse! I mean why gluing your sperm to your girl's skin if you can just inject it? That's much more convenient, right? And all you need is a syringe-like penis! And that's what several animals actually do. Yes, stabbing sex... And in the roughest cases that means piercing the female exoskeleton as happens in certain spiders and in an especially cruel way in bed bugs. Here the male wrestles the female to punch his dagger-like penis into her armored belly. If you really want to see that, click here...
Now, in any sane person's mind the one word "Why?" is reverberating. Why do some animals take sado-masochism to a penis-stabbing extreme? Well, for the guys the answer may be simple: It is the perfect rape - the female cannot prevent him from mating by shielding her genitals and other males cannot create any mating barriers against their competitors (Yes, that's a thing and boy, we have to talk about it one day!). And the females? Well, they have no choice. Or, to be precise, they have the choice of letting jerk males impregnate them or being the last generation with a picky partner choice... So they adapt. Female bed bugs actually have a receptive organ that allows them to survive the sex stabbing.
But nature wouldn't be nature if it couldn't top the bizarreness of traumatic insemination. Some flat worms do have a syringe penis used to inject sperm into their partners but they also are hermaphrodites. So when two meet - penis fencing! And yes, that's the term scientists use. There are two worms, fencing with their penises and the one that gets stabbed first acts as the female. And while that sounds kind of fair, it still sounds kind of bad. However, if the worms don't find a partner, they actually have sex with themselves. And where do you stab a syringe penis on your tail in self-insemination? Exactly, into the only body part you can reach - the head.
So the next time you wonder what the most extreme form of masturbation is - remember: It's self-penis-stabbing-into-the head...

The birds and the bees, part one

Okay, so you have been told about the birds and the bees. But do you really know how the birds are doing it? (Sorry, bees, we'll talk about you another time. Okay?) Because when you begin to think about it, there often are at least two points at which you begin to wonder: How do birds actually do it?

Passerine penisless passion

The first thing that may puzzle you is that most birds don't have a penis... (Oh boy, and we'll definitely have to talk about those that do at some point!) So how do you get sperm into a female cloaca without a penis? Of course, if you are female you immediately know the solution for ejecting fluid into something: Simply sit down! And that's more or less it. The act is called cloacal kiss and usually is really quick. And if you want to see that in a little movie, just go here. The actual act takes place at second 36 in case you missed it the first, second, or third time! Aaaaand in case you wondered: the picking of the cloaca probably is to remove sperm from the last guy.

So overall, bird sex is a bit like the movie cliche of a high-school ball date: The guy tries to impress her by his dancing, then does some clumsy foreplay and just as she is willing to mate and allows him to get really close, the very moment their genitals touch, everything is over already...

Okay, but now for the real puzzle, the one students actually ask almost every semester in our developmental biology course: How does a sperm fertilize a bird egg? I mean - it cannot go through the shell, right? Well, to cut a short story, even shorter: It doesn't. The actual ovum (the egg cell) is produced in the ovary and then filled with yolk, from which the chick is later fed. Then the ovum is fertilized, the egg white is added as a kind of aquarium for the embryo to grow into and finally the shell is added - with colorful sprinkles in the outer layer in some species and with a bubble of air for gas exchange. So the next time you enjoy a breakfast egg (most of which are not fertilized actually), take a moment to marvel at the miracle of the bird egg.

Simplified origin of a bird egg

Dance as if someone important is watching!

Let's imagine you're a little male spider. One day you may feel a little - let's say: romantic. So you begin to look for a female. But when you find one you get a little scared. She is bigger than you, so what if she assumes that you are an enemy or worse - a snack? So you hesitate, torn between fear and desire, twitching forward and back just at the edge of her field of view.

Trying to look cute - for a spider...

And she just watches. Her instincts don't label you as a rival and you're not behaving like food either. So the two of you mate successfully, while many of the non-twitchers got eaten or chased away.
Fast forward a few hundred or thousand generations - which are the same number of years for little spiders. Now all male spiders twitch, as they out bred the non-twitchers, and the females have learned that a twitching object is a mate.
But not all twitchers are the same! Some are more colorful and some move more elegantly. And both catch the female's eyes more easily. So now these will out breed the regular twitchers.
Fast forward another few thousand or million generations and the little shy spiders have become beautiful dancers! Some of them may get eaten by birds, as they are easier to spot. And that is why they may not get more flamboyant but overall the success with the ladies outweighs the risk by far!
Now you may think that this story is absurd. It might work for big, complex animals like birds, but spiders? And you are partially right, as most spiders have bad sight. However, jumping spiders don't. It pays off to have good eyes when you jump at your prey! And actually, among these tiny creatures there are some great dancers!
You still have doubts? Well, have a look at the mating dance of Saitis barbipes - a little Mediterranean spider that makes at least a great "twitcher".
And when that does not impress you properly, take a look of the Australian peacock spiders of the genus Maratus, some of which actually make peacocks look clumsy and bland, like this one or this, where the female also dances, or actually anything from this YouTube channel!
So the next time you are on the dance floor or admire a dancer, remember: There are little spiders in Australia, that might do it much better!

A girl's gotta eat, right?

Okay, let's face it - sex can be exhausting! For the guys the stressful part often is over after courtship and the actual act but if that was "successful" it's only beginning for the ladies - at least when they practice internal fertilization, egg-squirting fish are fine here. So when you have to nourish eggs or young it just makes sense to get a good protein-rich meal before, after or even during sex. And that's why female mosquitoes suck blood while the males are content with sugary plant juices. It is also why in some insects only female adults eat at all while the males prefer to be better flyers with an air-filled intestine.

But of course it would be much nicer if the guy invited her to dinner before having fun with her, right? It often works that way with humans, I've been told, and many animal suitors actually do bring a tasty mating gift, too. Well, actually, some females seem to have noticed, they all do... At least when you are carnivorous and larger than him. And that is why many spider males are very careful when they approach their desired mate as they always have to wonder - horny or hungry? And of course, there is always the risk of her being both and eating you afterwards, getting the love and the meal - yes, I'm looking at you, black widow!

So while a bit of sexy cannibalism seems to be a good deal for the female, why do male animals risk getting eaten? Well, that might be very simple - sex means possibly getting eaten but no sex means no offspring, so the overcautious ones might be extinct very fast. But... this isn't the whole story. Because sometimes getting eaten might be the best thing that can happen to you - well to your genes of course as you will be eaten. But your offspring might have a better start due to their well-fed mother. So if your chances are slim of finding another mate investing everything, really everything in that one chance may be your best bet. And there are animals that seem to have perfected that investment!

In preying mantises sexual cannibalism isn't as prevalent in the wild as it is in captive conditions but it does occur in up to a third of matings. And as the head of the male is what she can reach it gets eaten first - and that makes the male mate more enthusiastically. Because, in mantises, the lower body controls the thrusts and the brain actually slows things down, so when you bite off the head, the rest of the body makes sure that in this act it gives everything it can. Well, it's the last chance, so that does make sense. But there is always someone topping that... Australian Redback spider males actually bend towards their mates after copulating, offering their abdomen as a snack. And those that get eaten have more offspring in the end...

Of course, some ladies know how tasty a mate can be but do have the courtesy not to eat the father of their children. Where several species of North American fireflies occur in the same region, females and males use different codes of flashes to attract partners of the right species. And some females switch the code they flash after mating to attract other males as a post-coital snack. It may not surprise you that the male fireflies tend to approach every apparent sexy female quite carefully...

So, guys - the next time a woman looks at you lusting, licking her lips - just make sure, you impregnate her before she bites off your head! It may not safe your life and your sons and grandsons might inherit your suicidal sex drive but at least there might be many of them...

Further reading: Sexual cannibalism (Wikipedia)

Unexpected romance in the realm of insects

Okay, we have to talk. About termites. Gay termites, actually. Well, let me give you a short reminder on how termites usually live. A termite hive has a female that lays the eggs, called the queen and her offspring make up the worker and soldier castes of the hive. Sounds similar to ants and bees so far but there are some striking differences! One of these is that termites are way ahead in terms of equal rights than those matriarchal hymenopteres - not only are their worker and soldier castes made up by female and male animals, their mating also doesn't end in the males dying. Actually, the female and male don't mate during their nuptial flight but just meet there, then they build a shelter together and here they mate and raise their first children, relying on them for the further growth of the colony while queen and king live as a happy couple, producing more and more termites.

The hive may hide unexpected drama...

But what happens when fertile males don't find a female during their mating flight? Well, usually they have to die alone but at least in some termite species they found an alternative strategy - if they meet another lonely male they stop looking for a female, build a shelter and live together there. They even mate and as their mating behavior is different than that they use with females, you could consider that genuine gay insect sex and not just a desperate error.

"But..." you may ask "why? Aren't only those genes successful that lead to reproduction? How could specific gay behavior arise in insects? Is this finally proof of a gay creator?" Well, no, it isn't. Actually there seem to be some real benefits to having a gay relationship when you are a termite. The first is that termites in gay couples live much longer than those who struggle on their own. And sometimes the gay couples are able to take over a nearby hive, killing the king and one of them becomes the new king - the other one, well... maybe he can take over one day when his former gay lover dies...

It therefore seems that forming a gay couple is a good strategy, since even though your chances of one day taking over a colony may be very low, your chances of survival on your own are even lower. So the next time you meet some conservative parents who complain about their son's plans to move in with his boyfriend, just sneer at their lack of understanding on how to make it to the ranks of royalty!

Further reading: Male same-sex pairing as an adaptive strategy for future reproduction in termites (Mizumoto et al., Animal behavior, 2016)

The heartbreaking truth about tentacle monsters

Okay, let's start right away with something really naughty - tentacle sex! Some of you may have heard about that as a staple of weird Japanese animated erotica - and actually Wikipedia tells me that there are Japanese paintings of women and octopi getting naughty dating to the 19th century. Apparently that was supposed to circumvent censorship which prohibited obscenities. Yeah, that seems to make sense...

Tentacly, but not a monster!

Anyway, let's get to the real tentacle sex, shall we? Enter the cephalopods, i.e. squids and octopi - yes, they actually do have sex with their tentacles! Who knew you could actually learn something from weird 19th century Japanese porn? Actually the males have one or two special tentacles (called hectocotyli) which are used to store the sperm and transfer it to the female. Okay, for all of you who didn't really get that: The male octopus masturbates into his hand and then fingers (tentacles?) his mate to deliver the sperm. And when you think that this is strange, enter the argonauts: a group of octopi with a shell, where the males are much smaller than the females and actually detach their hectocotylus during mating and the tentacle actively swims into the female. And if you didn't really get that - let me describe it in other words: They masturbate into their hand, finger their girl and then lose the arm which is having the actual sex...So the next time someone tries to chat you up in a shady bar and tells you "Hey, baby - let me be your argonaut!" you'll know, that this guy is willing to make a sacrifice!

Then again, sex for cephalopods usually is quite exhausting and often ends in them dying afterwards, so losing your arm before death might not be that big of a sacrifice. But when it comes to octopi the story gets really heartbreaking. The female lays her eggs in a cave where they hang from the ceiling like grapes and guards them, not leaving them and waving fresh water at them until they hatch and their exhausted mother dies as her babies swim into the ocean.

And that's the real, weird, and dramatic story about tentacle sex. So the next time someone questions your choice in Japanese animated movies, just tell them that you despise those shallow Hollywood love stories and that you are looking for lovers who show real dedication!

Further reading: Hectocotylus (Wikipedia)