Cephalopod Sex and Reproduction

Wild Wunderpus photogenicus and Octopus cyanea employ asphyxiating ‘constricting’ in interactions with other octopuses Christine L. Huffard, Mike Bartick (2014) subscription
Abstract
Aggressive constricting including asphyxiation was observed in wild octopuses (Octopus cyanea Gray, 1849, and Wunderpus photogenicus Hochberg, Norman & Finn, 200616. Hochberg, F.G., Norman, M.D. & Finn, J. (2006) Wunderpus photogenicus n. gen. and sp., a new Octopus from the shallow waters of the Indo-Malayan Archipelago (Cephalopoda: Octopodidae). Molluscan Research 26, 128–140.
[Web of Science ®]
View all references). The distal portion of a dorsolateral arm formed a loop around the mantle of another octopus, in at least one case preventing the flow of water into the mantle, over the gills and out of the funnel. Constricting also may have prevented the subordinate individual from releasing ink, a possible irritant and predator attractant. A female O. cyanea used constricting as a form of fatal aggression to asphyxiate a male as part of apparent sexual cannibalism. This female killed a male with which she was mating using the ‘distance’ position. Constriction allowed a W. photogenicus to win during physical interspecific aggression with a close relative, Thaumoctopus mimicus Norman & Hochberg, 200532. Norman, M.D. & Hochberg, F.G. (2005) The ‘Mimic Octopus’ (Thaumoctopus mimicus n. gen. et. sp.), a new octopus from the tropical Indo-West Pacific (Cephalopoda: Octopodidae). Molluscan Research 25, 57–70.

View all references. This action took place near an immediately available food source and interrupted foraging by T. mimicus, providing possible evidence of interference competition among closely related sympatric cephalopod species in the wild.

Journalist review of the article
Female Octopus Strangles Mate, Then Eats Him
By Katherine Harmon Courage | July 22, 2014 |
The views expressed are those of the author and are not necessarily those of Scientific American.
Octopuses do the darndest things. Like kill their mate during matingby strangling him with three arms, according to new observations from the wild.
Enterprising scientists Christine Huffard and Mike Bartick watched wild octopuses in action. They found that, for males, mating can be a dangerous game. Especially when your lady has long limbs. Some of the more dicey encounters are detailed in a new paper, published online July 11 in Molluscan Research.
Hold on a second, you say. Strangling octopuses? Octopuses don’t even have necks—or inhale air. So how, exactly, does that work? The strangulation seems to happen when “an octopus wraps at least one arm around the base of the mantle of the competitor” (or mate), Huffard wrote in 2010. This constriction then keeps the octopus from taking in fresh water to run past its gills—starving the animal of its oxygen source.
Octopuses are not known to get cuddly with one another on a day-to-day basis. In fact, “octopuses touch each other with their arms primarily in the context of mating and aggression,” the researchers write. And in this case it seems to have been both.
Huffard came across a pair of mating day octopuses (Octopus cyanea) near Fiabacet Island in Indonesia. The female, as is often the case in this species, was larger—with a body about seven-and-a-half inches long; the male was closer to six inches long. They were positioned on a reef, outside the female’s den, the male’s mating arm (hectocotylus) inserted into the female’s mantle from a (presumably) safe distance.
After about 15 minutes of mating, the female inched closer to the male. And, as if lunging for a quick embrace, the female encircled the male’s mantle with her two front arms, “dragging him nearer,” the researchers describe. The female’s two arms wrapped around the male’s funnel and mantle opening. The male turned white (a common escape attempt response) and seemed to fight to slink away. But the female continued her constriction for two full minutes before wrapping an additional arm around the male. Two minutes after that, the male stopped moving.
“The female enveloped his body with her web and carried him to what appeared to be her den,” Huffard and Bartick write. Apparently the male was both date and dinner.
In a mess of 16 arms not all moves are obvious. But, like other acts of aggression, “such as grappling, arm-pulling and pushing,” the researchers note, the asphyxiation move is quite easy to spot—and is “easily distinguishable from non-aggressive arm uses employed during mating,” which include the male inserting his hectocotylus into the female’s mantle or the male’s grabbing the female’s mantle to draw her closer.
Males of this species tend to have fairly long hectocotylus arms. But, apparently, not always long enough. “A smaller male of average hectocotylus length mating by the ‘distance’ position can still be asphyxiated and killed by a larger female,” the researchers note. “When making a slight lunge forward, this large female was well within arm reach to capture and constrict a male mating”—even when he is doing so from a reasonable distance. “This observation shows that the ‘distance’ mating position can entail significant risk for a male”—especially a slightly smaller one. And it’s possible that “females might not be able to constrict males that mate with a relatively long hectocotylus,” which would give the male a head start and greater reaction time should the female start to attack.
Interestingly, in this species and others that are prone to sexual cannibalism by females, the males have especially long hectocotylus arms.
Although this male did not escape a grim fate, his genes may still live on. “Because this case of possible sexual cannibalism was post-copulatory this male might have ultimately fertilized some of the cannibalizing female’s eggs,” Huffard and Bartick write. Had he lived, however, he could have tried his luck with other females. Perhaps with a slightly less leggy lady.

The video is of two males fighting over the rights to a female but the suffocation method discussed is clearly visible.
 
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Squid Lady Parts
Danna Staaf (@Danna) 2014

I first saw squid pimples in 2006, on a research cruise in the Sea of Cortez. The little bumps around the female’s mouth looked exactly like whiteheads, as if squid could get clogged pores. They even oozed white stuff when you squeezed, but it wasn’t pus.

It was sperm.

I was just beginning as a graduate student, learning to extract eggs and sperm from Humboldt squid in order to study fertilization and development—or, as I glibly described my thesis, “squid sex and babies.” Though technically I wasn’t studying sex, since in squid copulation is separate from fertilization. Females mate and store sperm for weeks or even months before laying eggs.

We don't know how the female market squid who laid these egg cases selected which sperm was used to fertilize them. Males help out by pre-packaging their sperm into complex needle-like structures called spermatophores. Each spermatophore can ejaculate (yes, independently!) to become a spermatangium, a sticky sperm mass that attaches to the female’s skin. Then sperm from this mass moves into the little pimples I saw, which are called spermathecae. Confused yet? I sure was!

In the ship’s laboratory, we were able to fertilize eggs with sperm from spermatophores, spermatangia, and spermathecae[1]. But I’m pretty sure squid don’t lay their eggs in Petri dishes, so this doesn’t tell us a whole lot about natural reproduction. Which of the three sperm sources do females use to fertilize their eggs? Why bother with all the processing steps? Does it have to do with female selection or sperm competition?

No one knows, which is a bit surprising because spermatophores themselves have been studied quite intensively. Videos of spermatophore ejaculation and attachment can be found online, and I’ve written about more than one exciting new study. But this is the first time I’m writing about spermathecae, and it’s not because of recent research—it’s to popularize the lack of it.

Squid aren’t the only animals with well-studied male bits and mysterious female bits. A metastudy[2] published in May found similar disparities across phyla, from insects to mammals. The authors analyzed various possible explanations and concluded that cultural bias was to blame. A lingering assumption that sex comprises male activity and female passivity, they argued, has led researchers to prioritize male over female genitalia.

I learned about this study from Ed Yong’s excellent coverage, which included an interview with duck penis researcher Diane Kelly. She highlighted a significant practical reason for the research imbalance: male parts tend to be external and relatively static, while female parts are internal and highly dynamic. It’s a lot easier to pop a penis under the microscope than to visualize how a vagina changes shape during copulation.

But we scientists love challenges, right? So, to atone for my enthusiastic popularizing of research on male squid anatomy, here’s a call to action for research on female squid anatomy.

Why do Squids Have Penises but not Vaginas?

Squid reproductive anatomy starts out sounding familiar. They have separate sexes—none of this weird hermaphroditic stuff that’s so common in their snail cousins. A female squid makes eggs in an ovary, and when they’re ready for fertilization they travel down an oviduct. A male squid makes sperm in a testis, and when they’re ready to fertilize, they come out of a penis.

But scientists prefer to call the penis a “terminal organ” because it’s a bit different from what we’re used to: it doesn’t touch the female. It’s just an internal spermatophore extrusion device. The male reaches into his own body to grab the spermatophores with one of his eight arms, called a hectocotylus, which is specially modified for delivery service.

Now things start to get complicated.

Sometimes, in some species, the male places the spermatophores somewhere on the female’s body—on her head, or on the eight arms attached to her head, or around the mouth at the center of her arms. In other cases, the male places spermatophores inside the female’s body. But unlike the small orifices of our human bodies, all squid bodies have a large opening around the head. Seawater flows in to bathe the internal organs, and the male can reach in to drop off spermatophores. It’s nothing like a vagina, which leads exclusively to reproductive organs.

Whether inside or out, the spermatophores ejaculate and spermatangia glue themselves to the skin. They may even start to burrow in, and in some species they can get quite deep—scientists have wondered if the male actually bites a hole before depositing spermatophores[3].

Sperm can remain in the spermatangia until it’s time to fertilize. But females of many species also have special pockets for storing sperm, generally referred to as seminal receptacles. These can be external, in the skin next to the mouth, and there can be one or many (as in Humboldt squid). Other species have internal receptacles at or near the opening of the oviducts, such as the pharetra of bobtail squids[4]. These are probably the closest thing there is to a squid vagina.

This octopus is here to remind you that squid aren't the only cephalopods with mysterious lady parts. No one knows how sperm migrate from a spermantangium to a spermatheca. In reef squid, it’s been suggested that females move sperm with their arms[4]. Female pygmy squid have been seen grabbing spermatangia with their mouths, but only to remove or eat them, not to transfer them[5]. Some evidence suggests that the sperm could transfer themselves by swimming[6].

Wherever they’re stored, sperm must be released when the eggs are ready. If the sperm is inside the body, fertilization also happens inside; if not, the female extrudes the eggs and holds them in her arms—right next to her mouth. (See, that’s why sperm are so often placed there. I bet you thought squid were just orally fixated.)

As far as we know, all squid females mate with and store sperm from multiple males. Given the complexity of sperm processing and storage, there’s ample opportunity for the sperm to compete with each other and for the female to choose among them. But virtually nothing is known about either process.

Squids Are Weird, and Then Some Are Weirder

Every general statement I’ve made so far probably has an exception or five. For example, males of some squid species have not one, but two hectocotylized arms. Then, many deep-sea squids don’t have a hectocotylus at all. They tend to have a long penis, though, and in at least one species the penis can expand to the entire length of the body[7]. If, as Yong wrote, the story of duck penises is really the story of duck vaginas, then what is the real story behind these variations in male squid anatomy?

In the classic book Cephalopod Behavior, first published in 1996, Hanlon and Messenger reported: We know little about the influence of female choice during courtship ... We lack detailed observations and experimental studies of alternative mating tactics, sperm competition and reproductive success.... The morphology of the ... seminal receptacle in cuttlefishes and squids should be studied in greater detail and the details of spermatophore transfer recorded.

Almost twenty years later, these questions remain open. The female squid’s roles in copulation and fertilization remain opaque. It’s time to give squid ladies some respect! In the form of, er ... highly intrusive scientific research.

Danna Staaf is a freelance science and fiction writer with a doctorate in squid biology from Hopkins Marine Station of Stanford University. She tweets as @DannaStaaf and blogs at The Cephalopodiatrist.
 
The octopus that strangled its lover to death BBC © 2014

BBC Article from an interview with @mucktopus

In a single, extraordinary act, a female octopus surprises her mate, and changes how we think of her kind

Octopuses make for unusual lovers. To mate successfully, a male octopus must approach a female, and gently probe her with a single arm. He may grab her, but carefully, before inserting his arm up into her body, injecting packets of sperm.
After sex, a male octopus is probably not expecting to be probed by a female. He is not expecting to feel the brush of her arm, as it maliciously coils around his body. He is not expecting her to squeeze, cutting off the supply of water to his gills. He is not expecting to be held in a deadly, suffocating embrace.
Yet that exact fate befell one male common reef octopus swimming in the seas of Fiabacet Island, Indonesia.
In an extraordinary act, witnessed by scientists, the male octopus was strangled to death by his female lover, just moments after having mated with her.
The behaviour is so rarely seen that the incident, and a couple of others like it, may change our understanding of octopus behaviour.

Hunting a new mate? Or a new victim? (credit: David Fleetham / NPL)
Octopuses have long been considered relatively gentle creatures. Though they use their eight arms to catch prey, which is devoured using a large, sharp beak in their mouths, they tend to avoid aggression.
Octopuses are more likely to retreat from a threat, such as a predator, than to fight, and they tend to shy away from most confrontations with other animals, says Christine Huffard, a marine biologist at the Monterey Bay Aquarium Research Institute, at, Moss Landing, California, US.
In fact, octopuses spend most of their time, and use a variety of strategies, trying not to be seen. “Being overly aggressive to other animals on the sea floor would defy that strategy by attracting attention,” she says.
The more we get into the water and watch animals quietly from a distance, the more likely we might be to understand one day why female cephalopods might kill their mate
They can become aggressive with each other, particularly when fighting over food, dens, and mates. But they tend to grapple, pushing at each other, and pulling at their respective arms. They weren’t thought to be constrictors, strangling each other as a snake might suffocate its prey.
However, Christine Huffard and colleagues have witnessed two separate incidents of octopuses doing just that in the wild.

Suckers or weapons? (credit: Jeff Rotman / NPL)
The first occurred during a dive within 10 metres of water off Fiabacet Island, when the researchers came upon a female common reef octopus sitting exposed on a coral reef outside her den. Nearby, sat a slightly smaller male.
For 15 minutes the two animals mated. Then the female unexpectedly lunged forward, and with two arms, grabbed the male around his mantle, a structure octopuses use as a respiratory chamber to pass water through a funnel and across their gills. She dragged the male towards her. After two minutes, she then wrapped an arm around the opening to the mantle, and squeezed tight. After another two minutes, the male stopped moving. The female then enveloped the male’s body with her own and dragged him into her den, where the scientists presume she ate him.
Details of the grisly encounter are published in the journal Molluscan Research, along with those of a second encounter, this time between two octopuses of different species.

A male common reef octopus probes a female (credit: Georgette Douwma / NPL)
Then, divers observed a wonderpus octopus repeatedly approach and chase a mimic octopus foraging for food. The encounter seemed to end peacefully, but when reviewing images taken of the event, the scientists realised that the wonderpus octopus had actually wrapped an arm around the mantle of its rival, trying to strangle it.
Both incidents are reminiscent of another witnessed in 2007, when scientists observed one merciless female spend two days cannibalising a small male, having previously attacked and suffocated him after having mated with him 13 times.
For now, scientists do not know how common constricting might be in these or other octopuses in the wild. But such deadly struggles do appear to make octopuses unique; as the first invertebrates known to aggressively grasp and kill another animal using constricting.
Constricting might also prevent the subordinate octopus repelling the attack by expelling ink, which is also released through the funnel in the mantle. Expelling ink is a defensive tactic usually used to repel predators, as it clouds the water, and potentially contains irritating chemicals.

The deadly grasp of the female captured on camera (credit: C. Huffard)
For zoologist Mark Elgar of the University of Melbourne, Australia, an expert on invertebrate mating behaviour, the actions of the female octopuses make sense, given their eight-pronged anatomy.
“The specific method by which the female octopus captures and kills her mate – constricting him with her many legs – is novel, but only because this can be done only by an octopus,” says Elgar.
Huffard agrees. Octopuses are a type of mollusc known as a cephalopod, a group that also includes squid. “This unique anatomy opens doors to many behaviours that are unavailable to other molluscs, constricting being just one of them.”
Other invertebrates, such as insects and nudibranchs, are known to engage in sexual cannibalism.
None however, strangle their lovers.

A male wonderpus octopus is photographed strangling a rival (credit: Mike Bartick)
Female black widows and praying mantis are notorious for killing and eating males before, during or after sex. And similarly gruesome attacks have been observed in chironomid flies. A female chironomid uses her mouthparts to pierce the head of her male mate and, after extracting his body fluids as he transfers sperm to her, carries his desiccated carcass against her body for days.
Males are thought to be eaten as, once they have mated, they can be a valuable source of food. Male Argiope spiders, for example, tend to be consumed by the female after their second insemination.
For Huffard, this is a subject ripe for research: “People have studied that topic extensively in arthropods, especially arachnids, but not in rigorous studies using cephalopods.”
“The more we get into the water and watch animals quietly from a distance, the more likely we might be to understand one day why female cephalopods might kill their mate,” she says.
 
Sperm transfer or spermatangia removal: postcopulatory behaviour of picking up spermatangium by female Japanese pygmy squid
Noriyosi Sato, Takashi Kasugai, Hiroyuki Munehara 2014 (subscription)

Abstract
In the Japanese pygmy squid Idiosepius paradoxus, females often pick up the spermatangium using their mouth (buccal mass) after copulation. To examine whether the female I. paradoxus directly transfers sperm into the seminal receptacle via this picking behaviour, or removes the spermatangium, we conducted detailed observations of picking behaviour in both virgin and copulated females and compared the sperm storage conditions in the seminal receptacle between females with and without spermatangia picking after copulation in virgin females. In all observations, elongation of the buccal mass occurred within 5 min after copulation. However, sperm volume in the seminal receptacle was not related to spermatangia picking. Observations using slow-motion video revealed that females removed the spermatangia by blowing or eating after picking. These results suggest that picking behaviour is used for sperm removal but not for sperm transfer. Moreover, the frequency of buccal mass elongation was higher in copulated females than in virgin females, consistent with the sequential mate choice theory whereby virgin females secure sperm for fertilisation, while previously copulated females are more selective about their mate. Female I. paradoxus may choose its mate cryptically through postcopulatory picking behaviour.
 
Dimorphic sperm-transfer strategies and alternative mating tactics in loliginid squid
Yoko Iwata1, Yasunori Sakurai2, Paul Shaw3 2014 (subscription)

Abstract
Animal species usually have a single sperm-storage site in the female body, but females of the squid Heterololigo bleekeri possess two distinct sperm-storage sites simultaneously. Use of two sperm-storage sites correlates with alternative male mating behaviours: large consorts guard females and place spermatophores inside the oviduct just before spawning, whereas small ‘sneaker’ males place spermatophores on the membrane around the female's mouth within the arm crown, where a seminal receptacle is present. Previous work showed that spermatophore and sperm morphology diverge between consort and sneaker males. Here we show novel dichotomous adaptations in the sperm-transfer strategy of males of this squid, associated with the use of two distinct sperm-storage sites on females. The spermatangia ejaculated from spermatophores were clearly dimorphic: all spermatangia ejaculated from spermatophores smaller than 12 mm from small sneaker males were drop-shaped, whereas all spermatangia from spermatophores longer than 12 mm from larger consort males were rope-shaped. In addition, the drop-shaped spermatangia were distinct in having a spine on their base, which might reduce the risk of it being shed from the female's body surface. Our findings suggest that existence of alternative sperm-storage sites, and related biological and environmental factors, lead to the evolution of divergent sperm-transfer strategies.
 
Role of olfaction in Octopus vulgaris reproduction
Gianluca Polese , Carla Bertapelle , Anna Di Cosmo 2014 (subscription)

Abstract
The olfactory system in any animal is the primary sensory system that responds to chemical stimuli emanating from a distant source. In aquatic animals “Odours” are molecules in solution that guide them to locate food, partners, nesting sites, and dangers to avoid. Fish, crustaceans and aquatic molluscs possess sensory systems that have anatomical similarities to the olfactory systems of land-based animals. Molluscs are a large group of aquatic and terrestrial animals that rely heavily on chemical communication with a generally dispersed sense of touch and chemical sensitivity. Cephalopods, the smallest class among extant marine molluscs, are predators with high visual capability and well developed vestibular, auditory, and tactile systems. Nevertheless they possess a well developed olfactory organ, but to date almost nothing is known about the mechanisms, functions and modulation of this chemosensory structure in octopods. Cephalopods brains are the largest of all invertebrate brains and across molluscs show the highest degree of centralization. The reproductive behaviour of Octopus vulgaris is under the control of a complex set of signal molecules such as neuropeptides, neurotransmitters and sex steroids that guide the behaviour from the level of individuals in evaluating mates, to stimulating or deterring copulation, to sperm-egg chemical signalling that promotes fertilization. These signals are intercepted by the olfactory organs and integrated in the olfactory lobes in the central nervous system. In this context we propose a model in which the olfactory organ and the olfactory lobe of Octopus vulgaris could represent the on-off switch between food intake and reproduction.

Related findings of olfactory system effecting sexual maturation:

Control of GnRH expression in the olfactory lobe of Octopus vulgaris (pdf)

The presence of APGWamide in Octopus vulgaris: a possible role in the reproductive behavior
 
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SQUID
Threat of Being Eaten Doesn’t Deter Dumpling Squid From Sex

... To see how the squid behave in the face of danger, researchers from the University of Melbourne collected 15 pairs of wild dumpling squid from the waters off Victoria, Australia. They also scooped up 15 of one the squid’s most common natural predators, a type of fish called the sand flathead. They put each squid pair into separate containers, then exposed them to various kinky scenarios, including introducing a predator before the squid began to mate, during mating and an hour after mating. The researchers noted any defensive behaviors, such as blowing out a cloud of ink to mask their presence or jetting away by quickly ejecting water out of the body. ...
 
How Male Octopuses Avoid Being Eaten by Hungry females

Nice layperson's article discussing numerous mating habits of octopuses. Do note that the two siphon statement (as well as using the siphon at all in mating) needs correction but it covers the subject rather well.


Presented by
Katherine Harmon Courage

Male octopuses have a big problem: female octopuses. Each male wants to mate and pass on his genes to a new generation. The trouble is, the female is often larger and hungrier than he is, so there is a constant risk that, instead of mating, the female will strangle him and eat him.

The males have a host of tricks to survive the mating process. Some of them can quite literally mate at arm's length. Others sneak into a female's den disguised as another gal, or sacrifice their entire mating arm to the female and then make a hasty retreat.

It's all very macabre. It's also a paradox. Octopuses are some of the most antisocial, unfriendly animals alive. Yet their bodies have evolved in such a way that they must mate in the most intimate way possible: the male has to insert his sperm directly into the female's body using one of his arms. The resulting mating practices are not just a curiosity: they are a window onto how octopuses have evolved into the creatures they are today.

Wunderpus octopuses (Wunderpus photogenicus) mating (Credit: Roy Caldwell)

Octopuses and their close cousins the squid all belong to a group of animals called cephalopods. Both are actually molluscs, making them close relatives of oysters and limpets, but they have lost their shells.

Octopuses tend to be profoundly antagonistic towards each other. Unlike gregarious animals like dolphins, they appear to see their own kind primarily as competition, and sometimes food.

There's always the threat of cannibalism
Squid, which are downright social by comparison, mate in a distinctly unromantic way. A male squid swims by and deposits sperm in one quick move outside of the female's body. She can decide later whether to accept it.

But not so the octopus. "Octopus mating is definitely different than other cephalopods," says marine biologist Jean Boal of Millersville University in Pennsylvania. The male must deposit his sperm inside the female's body, at the risk of his life.

"There's always the threat of cannibalism," says Richard Ross of the California Academy of Science's Steinhart Aquarium.


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Two day octopuses (Octopus cyanea) mating (Credit: Georgette Douwma / NPL)

We don't know how often female octopuses eat the males, but Christine Huffard of the Monterey Bay Aquarium Research Institute in California has seen it happen many times.

She strangled him and took him back to her den to feed on
In one instance, she and her colleagues observed two day octopuses mating on a reef in Indonesia. After about 15 minutes of copulation, the female lunged and wrapped two arms around the male's bulbous body, his mantle. A few minutes later, the male was motionless. The female then carried the corpse to her den, where he presumably became dinner.

In another instance, researchers watched a large female day octopus off the coast of Micronesia. A small male mated with her a dozen times. But then the male went in for a 13th mating session, and the female turned on him. She strangled him and took him back to her den to feed on over the course of the next two days.

Sexual cannibalism does happen in nature - witness the male-eating praying mantis and black widow spiders - but strangulation during mating is a rarity, Ross says. It may not be all bad for the male, though.

As Huffard and her colleagues point out in a 2014 paper describing one of the male-eating incidents, the felled male probably managed to fertilize some of the female's eggs - accomplishing his life's mission despite his unfortunate demise. What's more, females generally make hundreds or even hundreds of thousands of eggs, so just one successful copulation can produce a vast number of offspring.

The male's main tool for this daunting endeavour is a specialized mating arm, known as the hectocotylus. When he is not engaged with a female, the mating arm works just like his other seven arms. It is able to bend, stretch and exert suction. But the mating arm also comes with extra bells and whistles.

For big species, mating can last at least half an hour
For one, it has a central groove. The male releases packets of sperm called spermatophores into this groove, for their journey to the female. The arm's tip is also equipped with erectile tissue, not unlike that found in the human penis, which provides stiffness that helps guide the arm into the female's body. The arm goes in through one of the two siphons on the female's mantle, which she also uses to breathe, expel waste and jet out water for swimming.

The destination for these spermatophores is the female's small oviducal gland, a sort of holding area. When she lays her eggs, which could be days or even months later, they will pass this area and be fertilised.

The male needs to keep his mating arm tip inside the female long enough to transfer at least one spermatophore, and preferably more. In some smaller species this might take just a couple minutes, says Jennifer Mather of the University of Lethbridge in Alberta, Canada. But for big species like the giant Pacific octopus, mating can last at least half an hour.

But being soft-bodied, they can't indulge for too long. "If you get all wrapped up in mating, you're very, very vulnerable to predators," says Mather.


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Giant Pacific octopus (Enteroctopus dofleini) on the sea bed (Credit: Jeff Rotman / NPL)

As a general rule, it's the male octopuses that approach the females.Then the males tend to take one of two approaches in attempting insemination.

The first is a risky position called the "mount". "The male grabs onto the female's mantle with all his arms, and reaches into her mantle with his mating arm," says Huffard.

This style of mating tends to be more popular in species with shorter arms, says Huffard. Females of these species may be less likely to eat their mates. Possibly, species in which males are more likely to be devoured during sex have evolved longer arms, which would make mating a little safer for the males.

Algae octopuses (Abdopus aculeatus) mating (Credit: Roy Caldwell)

More cautious males opt for the "reach". "The male sits near the female and reaches over to her only with the mating arm," says Huffard.

This allows him to keep his distance. "The male will extend his arm as long as he can and try to accomplish the copulation from as far away as he can," says Boal.

The "reach" tactic is more common in octopuses with longer arms, which may be the ones where female cannibalism is more likely. An extra-long reach means that the male can stretch his arm into a resting female's den and mate with her without even venturing inside.


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Male algae octopuses (Abdopus aculeatus) mate from a distance (Credit: Roy Caldwell)

The algae octopus is one such cautious mater. "Males have a very long mating arm," says Huffard. "They stretch this arm to twice its resting length when mating." Just to be on the safe side, "these males also frequently mate with females that are busy foraging for food". These females ought to be too busy to eat him.

The "reach" approach also keeps the male's other seven arms free, so he can defend himself if need be, says Ross. This may be why the coconut octopus practices distant sex.

The "reach" tactic might also be advantageous for the female. In theory, she could entertain two male suits at once, says Huffard: one in each siphon.

For male argonauts, mating costs an arm (Credit: David Shale / NPL)

In some species, male octopuses have moved beyond the "reach". They just give the female their spermatophore-loaded mating arm, and swim away to safety.

A detached mating arm might be a logistical necessity
Male argonaut octopuses are smaller than the females, and the male's hectocotylus simply stays intact inside the female's mantle "until the female is ready to use the sperm for fertilization", Mather says.

It was actually this behaviour that earned the hectocotylus its name. In the early 19th century the zoologist Georges Cuvier discovered strange foreign objects in female argonaut octopuses and thought they must be a type of parasitic worm. He called them Hectocotylus octopodis, and the name stuck.

For blanket octopuses, a detached mating arm might also be a logistical necessity. The females can be 2m long, while the males are just a few centimetres. So the male "removes the arm that carries the sperm, and the arm goes into the [female's] mantle cavity," says Ross. "That's a pretty extreme strategy to not get eaten."


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Greater blue-ringed octopuses (Hapalochlaena lunulata) mating (Credit: Roy Caldwell)

But it's not all rough-and-tumble, strangulation and arm removal. Algae octopuses are slightly more tolerant of each other than most species, and as a result their mating behaviours are more nuanced.

They have even been known to disguise themselves as females
Males of this species have other males as well as females to fear when attempting to mate. The largest males often have the privilege of guarding a desirable female and mating with her repeatedly. Smaller males have no chance of driving them off, and they know it. "Males appear to alter their mating tactics, based on their local chances of winning fights with rivals," says Huffard.

The smaller males wait until a larger guarding male has left the den, then covertly mate with the female. As a result, they are called "sneaker" males. They have even been known to disguise themselves as females, hiding their hectocotylus to make a less threatening approach to a guarded female.

This sly tactic can occasionally backfire, as it did in an instance caught on film by Huffard. A sneaker male approached a burrow where he seemingly sensed a female was hiding. As he reached an arm in, an octopus emerged. But it was not the female: it was her guarding male. Unsurprisingly, this big male was not impressed by the sneaker male's attempt to insert a hectocotylus into his mantle. The small male only narrowly escaped the ensuing fight.

A giant Pacific octopus (Enteroctopus dofleini) (Credit: Brandon Cole / NPL)

These cunning tactics pale in comparison to the behaviour of one newly-discovered octopus species. The larger Pacific striped octopus has not yet been formally described. But its sexual habits break all the rules for octopuses.

They mate beak-to-beak
The larger Pacific striped octopus is one of the few known gregarious octopuses. These octopuses can live together, even in close quarters, without eating or otherwise maiming each other.

This tolerance carries through to their mating habits. "They mate beak-to-beak, mouthpart-to-mouthpart," says Ross, who has witnessed numerous mating sessions. This is bizarre, because octopuses' sharp and strong beaks are their most dangerous weapons.

In this unusual position, a pair of octopuses will spread their arms out together, so that the suckers seem to touch. "That's a really, really strange thing," says Ross.

A female lesser Pacific striped octopus (Octopus chierchiae) (Credit: Roy Caldwell)

The larger Pacific striped octopus has a close cousin, the imaginatively-named lesser Pacific striped octopus. These are much more typical. "The male jumps on top of [the female's] mantle, away from her arms," says Ross. "It's an amazingly quick movement, in case she's in a bad mood or something. Then they mate, and he moves away as fast as he can."

When octopuses mate there are 16 arms to keep track of
No one knows why the larger Pacific striped octopus is so much more sociable than other species. Its apparent oddity reminds us that we don't really understand octopus sex in general. Why would such a voracious, antisocial animal mate so intimately?

Perhaps, despite the scale of the sexual cannibalism, few enough males meet their doom at their mates' hands, er, arms - and enough of them manage to pass on sperm. If that's the case, there might not be much evolutionary pressure on the males to evolve a safer way to mate.

"No one's really worked all of this out," says Mather. That may be in part because only a handful of species have been studied so far. "We have a vague understanding of mating in about a dozen shallow-water octopuses," Huffard says. "That leaves over 275 shallow-water species to go, and all of the deep-water species." Those deep-water octopuses might hold evolutionary clues to what early octopus sex looked like.

It may be some time before we truly understand why octopuses have sex the way they do. Part of the problem is that they are extraordinarily difficult to study. There are the obvious problems that they live underwater and are masters of camouflage. But even more challenging, when octopuses do get together there are 16 arms to keep track of. "It's really difficult to see what's going on," says Ross.
 
Yeah I don't know where the two siphon (funnel) idea comes from. My guess is that people think that octopuses have two funnels because some octopus toys have two funnels. I think people model the toys based on photos, and many photos show the movable funnel, no matter which side the images is from
 
Actually, she SHOULD know better as she (Harmon) has a journalist book out about cephs. I also don't know where the idea comes from that the siphon has anything to do with reproduction.
 
Octopus
Distance chemoreception and the detection of conspecifics in Octopus bimaculoides

Matthew D. Walderon, Kevin J. Nolt, Robert E. Haas, Krista N. Prosser, Johanna B. Holm, Gregg T. Nagle, Jean G. Boal 2011 (full article)


Octopuses are solitary predators that typically use their arms to grope into crevices to find food. They detect odours on contact using chemosensory cells on their lips and suckers (Budelmann, 1996). They can also detect water-borne odours (distance chemoreception) using receptors in their olfactory organs (olfactory pits; Budelmann, Schipp & Boletzky, 1997). Behavioural experiments have demonstrated increased arousal (Boyle, 1983), activity (Boyle, 1986) and attraction (Chase & Wells, 1986;Lee, 1992) in response to food-related odours, but responses to odours of conspecifics have not previously been investigated. Chemical communication has been demonstrated previously in cephalopods, such as Nautilus (Basil et al., 2002), Loligo (Gilly & Lucero, 1992; Buresch et al., 2003; King, Adamo, & Hanlon, 2003) and Sepia (Boal, 1997; Boal & Marsh, 1998; Boal et al., 2010). Here we investigate behavioural evidence for detection and attraction to conspecific odours by Octopus.
 
Octopus researcher a sucker for hard work
Interesting new research but no paper yet.

THE sex life of an octopus is the subject of a study by University of WA Ocean’s Institute-backed James Cook University researcher Peter Morse this summer.

“We want to know just how the females are choosing some males’ sperm over others, because there are often many fathers in any egg clutch,” Mr Morse (28) said.

Last summer, his traps for the cephalopods along the WA coast, including Cottesloe and South Fremantle, contributed to results published in the science journal Behaviour last month.

The venomous male southern blue-ringed octopus being studied is allocated about 50 sperm during its seven-month life.

Females store different males’ sperm in a gland behind their heads, before potentially deciding which to use to fertilise precious eggs, then they dig a burrow or hide to protect their young.

The mothers eventually die after protecting the eggs for two months, while the males die when they have exhausted their sperm.

“We also would like to know how the males seem to be aware of how much sperm the females are holding, and because they have a limited amount of sperm in a lifetime they seem to be regulating the amount they are using,” Mr Morse said.

His previous studies indicated males appear to be able gauge just how much sperm from their competitors are being held by the females and males change the amount of sperm they leave with a female, while ensuring they have enough left for mating with other females.

“They seem to strategically allocate their limited sperm,” Mr Morse said.

Last month, he started weekly collections from about 200 octopus traps 50m-100m offshore from South Fremantle power station, near to where he trapped more than 110 animals in Cockburn Sound a year ago.

”What we’re doing is verifying the behaviour indicated by our previous research that showed males mate to maximise retention of a limited amount of sperm,” Mr Morse said.

“We are trying to determine how the different times spent by a male mating with a female affects the pattern of fatherhood.”

The traps, which Mr Morse collects by snorkelling, should not be disturbed and have AIMS Research written on their buoys.
 
Octopus - Mating Mimics
Published on Apr 3, 2013
These mimic octopus are known for impersonating other creatures ... this time they are just getting amorous! In this unique video you can see the mating struggle of the mimic octopus and also the hilarious reaction of our underwater cameraman - Christian Loader.

 
SQUID
When should male squid prudently invest sperm?

Amy K. Hoopera,Benjamin J. Wegenera, Bob B.M. Wonga 2016 (subscription)

Ejaculate production can be costly and males are expected to prudently allocate this potentially limiting resource to higher quality females. However, relatively little is known about facultative sperm allocation in response to the quality distribution of sequentially encountered females, despite this being a more realistic scenario for males in many species. Here, we examined patterns of male investment in a squid, Sepiadarium austrinum, when presented sequentially with small versus large females. Owing to a positive size – fecundity relationship in this species, large and small females are expected to differ in terms of their perceived quality to males as potential mating partners. Yet, despite large sperm investment and significant variation in female quality, sperm investment was determined only by mating order, with males consistently decreasing sperm investment in second matings. These results highlight that, when mates are encountered sequentially rather than simultaneously, prudent sperm allocation may not occur when it is otherwise predicted.
 

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