Tag Archives: reproduction

These hard-bodied robots can reproduce, learn and evolve autonomously

Where biology and technology meet, evolutionary robotics is spawning automatons evolving in real-time and space. The basis of this field, evolutionary computing, sees robots possessing a virtual genome ‘mate’ to ‘reproduce’ improved offspring in response to complex, harsh environments.

Image credits: ARE.

Hard-bodied robots are now able to ‘give birth’

Robots have changed a lot over the past 30 years, already capable of replacing their human counterparts in some cases — in many ways, robots are already the backbone of commerce and industry. Performing a flurry of jobs and roles, they have been miniaturized, mounted, and molded into mammoth proportions to achieve feats way beyond human abilities. But what happens when unstable situations or environments call for robots never seen on earth before?

For instance, we may need robots to clean up a nuclear meltdown deemed unsafe for humans, explore an asteroid in orbit or terraform a distant planet. So how would we go about that?

Scientists could guess what the robot may need to do, running untold computer simulations based on realistic scenarios that the robot could be faced with. Then, armed with the results from the simulations, they can send the bots hurtling into uncharted darkness aboard a hundred-billion dollar machine, keeping their fingers crossed that their rigid designs will hold up for as long as needed.

But what if there was a is a better alternative? What if there was a type of artificial intelligence that could take lessons from evolution to generate robots that can adapt to their environment? It sounds like something from a sci-fi novel — but it’s exactly what a multi-institutional team in the UK is currently doing in a project called Autonomous Robot Evolution (ARE).

Remarkably, they’ve already created robots that can ‘mate’ and ‘reproduce’ progeny with no human input. What’s more, using the evolutionary theory of variation and selection, these robots can optimize their descendants depending on a set of activities over generations. If viable, this would be a way to produce robots that can autonomously adapt to unpredictable environments – their extended mechanical family changing along with their volatile surroundings.

“Robot evolution provides endless possibilities to tweak the system,” says evolutionary ecologist and ARE team member Jacintha Ellers. “We can come up with novel types of creatures and see how they perform under different selection pressures.” Offering a way to explore evolutionary principles to set up an almost infinite number of “what if” questions.

What is evolutionary computation?

In computer science, evolutionary computation is a set of laborious algorithms inspired by biological evolution where candidate solutions are generated and constantly “evolved”. Each new generation removes less desired solutions, introducing small adaptive changes or mutations to produce a cyber version of survival of the fittest. It’s a way to mimic biological evolution, resulting in the best version of the robot for its current role and environment.

Virtual robot. Image credits: ARE.

Evolutionary robotics begins at ARE in a facility dubbed the EvoSphere, where newly assembled baby robots download an artificial genetic code that defines their bodies and brains. This is where two-parent robots come together to mingle virtual genomes to create improved young, incorporating both their genetic codes.

The newly evolved offspring is built autonomously via a 3D printer, after which a mechanical assembly arm translating the inherited virtual genomic code selects and attaches the specified sensors and means of locomotion from a bank of pre-built components. Finally, the artificial system wires up a Raspberry Pi computer acting as a brain to the sensors and motors – software is then downloaded from both parents to represent the evolved brain.

1. Artificial intelligence teaches newborn robots how to control their bodies

Newborns undergo brain development and learning to fine-tune their motor control in most animal species. This process is even more intense for these robotic infants due to breeding between different species. For example, a parent with wheels might procreate with another possessing a jointed leg, resulting in offspring with both types of locomotion.

But, the inherited brain may struggle to control the new body, so an algorithm is run as part of the learning stage to refine the brain over a few trials in a simplified environment. If the synthetic babies can master their new bodies, they can proceed to the next phase: testing.

2. Selection of the fittest- who can reproduce?

A specially built inert nuclear reactor housing is used by ARE for testing where young robots must identify and clear radioactive waste while avoiding various obstacles. After completing the task, the system scores each robot according to its performance which it then uses to determine who will be permitted to reproduce.

Real robot. Image credits: ARE.

Software simulating reproduction then takes the virtual DNA of two parents and performs genetic recombination and mutation to generate a new robot, completing the ‘circuit of life.’ Parent robots can either remain in the population, have more children, or be recycled.

Evolutionary roboticist and ARE researcher Guszti Eiben says this sped up evolution works as: “Robotic experiments can be conducted under controllable conditions and validated over many repetitions, something that is hard to achieve when working with biological organisms.”

3. Real-world robots can also mate in alternative cyberworlds

In her article for the New Scientist, Emma Hart, ARE member and professor of computational intelligence at Edinburgh Napier University, writes that by “working with real robots rather than simulations, we eliminate any reality gap. However, printing and assembling each new machine takes about 4 hours, depending on the complexity of its skeleton, so limits the speed at which a population can evolve. To address this drawback, we also study evolution in a parallel, virtual world.”

This parallel universe entails the creation of a digital version of every mechanical infant in a simulator once mating has occurred, which enables the ARE researchers to build and test new designs within seconds, identifying those that look workable.

Their cyber genomes can then be prioritized for fabrication into real-world robots, allowing virtual and physical robots to breed with each other, adding to the real-life gene pool created by the mating of two material automatons.

The dangers of self-evolving robots – how can we stay safe?

A robot fabricator. Image credits: ARE.

Even though this program is brimming with potential, Professor Hart cautions that progress is slow, and furthermore, there are long-term risks to the approach.

“In principle, the potential opportunities are great, but we also run the risk that things might get out of control, creating robots with unintended behaviors that could cause damage or even harm humans,” Hart says.

“We need to think about this now, while the technology is still being developed. Limiting the availability of materials from which to fabricate new robots provides one safeguard.” Therefore: “We could also anticipate unwanted behaviors by continually monitoring the evolved robots, then using that information to build analytical models to predict future problems. The most obvious and effective solution is to use a centralized reproduction system with a human overseer equipped with a kill switch.”

A world made better by robots evolving alongside us

Despite these concerns, she counters that even though some applications, such as interstellar travel, may seem years off, the ARE system may have a more immediate need. And as climate change reaches dangerous proportions, it is clear that robot manufacturers need to become greener. She proposes that they could reduce their ecological footprint by using the system to build novel robots from sustainable materials that operate at low energy levels and are easily repaired and recycled. 

Hart concludes that these divergent progeny probably won’t look anything like the robots we see around us today, but that is where artificial evolution can help. Unrestrained by human cognition, computerized evolution can generate creative solutions we cannot even conceive of yet.

And it would appear these machines will now evolve us even further as we step back and hand them the reins of their own virtual lives. How this will affect the human race remains to be seen.

Tetrax_tetrax

Grassland birds will struggle to have babies because of climate change

Global warming is going to make everything hotter — except birds’ dating lives, new research shows.

Tetrax_tetrax
Image via Pixabay.

A new study published by researchers at the University of East Anglia (UEA) and the University of Porto (CIBIO-InBIO) reports that global warming could reduce the mating activity and success of grassland birds.

Hot singles in your area

“This work has shown how global warming may affect important behavioral mechanisms using the mating system of a lekking grassland bird species as an example,” says Mishal Gudka, who led the research while at UEA’s School of Biological Sciences.

The study examined the little bustard (Tetrax tetrax), a species of grassland bird that’s classified as a vulnerable species in Europe. The aim of the study was to see how rising mean temperatures could affect the future behavior of this (as well as other related) species.

Male little bustards, like male humans, spend most of their time in April and May trying to attract females. They do so in gatherings known as leks. They will bunch up together in a lek and stand upright, letting out a bellowing call to get noticed by prospective mates. Such calls are also employed to scare off competing males from their territory.

The team, with members from the UK, Kenya, Portugal, Spain, and Brazil report that high temperatures reduced this call display behavior among males. Their hypothesis is that if conditions get too hot, the birds have to make a choice between attempting to mate or finding shelter to protect themselves from the heat and save energy.

The team used remote GPS/GSM accelerometer tracking devices that were fitted to 17 wild male little bustards living at five sites in Spain and Portugal. The birds were filmed while the accelerometers recorded their position to record their behavior. Using this data, the team was able to determine the acceleration signature or pattern for snort-calling behavior, which they then tracked for the present study.

Little bustard display behavior is significantly related to temperature and to the particular stage of the mating season reached, the team reports. The average temperature of each day has been inversely linked to how much display behavior the males put out: the higher the temperature, the lower display rates become. The study focused on a region of the Iberian Peninsula (Spain and Portugal) where average daily daytime (5:00—21:00 hours) temperatures varied between 10ºC and 31ºC. Snort-call display probability decreased substantially as temperature increased from 4 to 20ºC, stabilized from 20 to 30ºC, and decreased thereafter.

The team reports that, based on these findings and temperature projections in the area, the average display activity of the birds will drop by 10% by 2100.

“Many people are familiar with the impacts of global warming on wildlife through droughts, storms or wildfires as well as earlier migration with warming springs,” says co-author Paul Dolman, Professor of Conservation Ecology at UEA’s School of Environmental Sciences. “But climate change affects species in many other subtle ways that may cause unexpected changes.”

“Little bustards living in the Iberian Peninsula are already exposed to some of the highest temperatures within their species range. They are one of many bird and mammal species that have an extravagant, energetically demanding display ritual, meaning they are all susceptible to the same issue.”

The paper “Elevated temperature affects male display activity of a lekking grassland bird” has been published in the journal PLOS ONE.

Sperm plants.

NASA is sending sperm to the ISS — here’s why

The last resupply shuttle sent to the ISS brought the crew over 5,000 pounds of supplies and a few samples of sperm, to boot.

Sperm plants.

Image credits Thomas Breher.

Ever dream of going to space, maybe even blast off to a new life on Mars? I sure do. What about finding that special someone to love, someone to settle down and start a family with? Well, I have some good news and some bad news: you can probably do either of the two — but currently, we don’t know if you can do both at the same time.

The birds, the bees and the Falcon 9

Put quite simply, we don’t know how to succeed at the deed in space. We don’t even know if we can actually reproduce in microgravity, if all the biological cogs function as intended outside the environmental conditions of Earth. Luckily, NASA has our back, and they’re starting from the basics: last week, the agency sent several sperm samples to the ISS, planning to observe how the cells behave in space. It may sound silly, but knowing whether or not we can make babies in space (and how to best go about it) could make the difference between a successful deep-space mission or a complete failure.

As part of the “Mission Micro-11“, astronauts aboard the ISS will receive and then test samples of human and bull semen (these will act as controls). What NASA wants to determine right now is if the sperm can move with enough freedom and speed to fuse with an egg inside the station’s Microgravity Science Glovebox — an instrument which NASA amusingly describes as “particularly suited for handling hazardous materials when the crew is present.”

Before you ask — yes; yes there are six full-grown men aboard the ISS right now, and one can’t help but observe they might have had a different method of obtaining such samples you know, handy. NASA, however, didn’t want to have them go above and beyond the call of duty, with LiveScience’ Rafi Letzter noting it’s “understandable why the space agency didn’t go that route, if for no other reason than the limits of what can be reasonably demanded in even an outer space workplace.”

[Read More] Nobody’s in a loving mood when faced with a lack of food — not even astronauts. So here’s what they used to eat, what they eat today, and a look at what they’ll eat on the treck to Mars.

Chuckling aside, the experiment should help us gain a better understanding of how these cells fare in space — especially since previous research has shown that the lack of gravity could interfere with the normal functioning of sperm. While the cells themselves might be able to function properly, we still don’t know if they can actually fuse with the egg in these conditions.

Still, don’t give up on astronaut school just yet — right now, we’re looking at how well reproductive cells would function aboard the ISS. Later research will have to determine everything else: can humans give birth in microgravity? Can we insulate newborns from space radiation, and if not, how will it affect their development? And, perhaps most excitingly, how exactly does one go about having sex in outer space?

I for one, am willing to dedicate my body to that bit of science.

Why do bachelors exist in the animal world?

Imagine a pride of lions: one regal male residing elegantly over his hard-won harem of females, shaking out his mane and lying his lovely, savage head upon his paws as the hot sun beats down. The lions eat the gazelles, the gazelles feed on the grass, and nature’s great balance (one might even say, the circle of life) is at peace. Except, wait a tic: where are all the other boy lions? How can there be so many females and so few males? That doesn’t seem balanced at all.

Those bachelors who are unable to mate, or as science mercilessly refers to them, “zero-class males,” have probably formed a bachelor posse and are roaming the savannah elsewhere doing their best to stay alive. But Charles Darwin would interject: if they are not reproducing, then why has nature selected them to exist? Evolutionary theory is pretty ruthless about it: any strategy that consistently fails to reproduce shouldn’t persist because such individuals will ultimately die off without passing on their genes. And yet.

The different appearances of the bluegill sunfish; illustration by Sarah Nason

Some bachelors are just biding their time before they make their move, like a calculating Scar waiting for an opportune wildebeest stampede. Eventually, the harem’s current owner will age and weaken and one of our young, strong bachelors can successfully fight him for ownership. But a lot of animal systems don’t work that way: oftentimes, the bachelors will never grow to be strong enough to face off against a dominant harem owner. For example, take the bluegill sunfish. Bizarrely, only a certain number of males reach a large body size and defend nests of females’ eggs; meanwhile, a separate faction of miniature males (smaller even than the female) apparently wanders aimlessly.

And they’re not exceptional: these tiny wandering males can make up nearly a third of the male population. Evolution, are you drunk?

Turns out, most bachelors are probably not single

Predictably, even though it looks like it makes no sense, nature knows exactly what it’s doing. To the naked eye, it appears that these bachelors have no way of mating and should be dubbed as “zero-class.” (rough.) However, after watching their behaviour more closely, biologists figured out that the smaller males were using entirely different tactics compared to their dominant counterparts. Their small and agile bodies make them well suited for a decidedly underhanded, but effective, alternative mating strategy: “sneaking.” While the dominant male’s back is turned, the sneaker male darts quickly in, sprinkles some sperm on the female’s eggs, and is gone in an instant.

Genetic studies later confirmed these nefarious tactics, showing that the dominant male defending a nest fathers less than 80% of the offspring on average. Meaning not only are our so-called bachelors able to sneak in there, but they must also possess some pretty aggressive sperm to grab that big of a slice of the paternity. This leads us to a fascinating niche of evolutionary biology called sperm competition, which is exactly what you think it is: sperm duking it out against each other for the prize of fertilizing an egg.

What do sperm battles look like?

In the case of group-spawning animals like fish, sperm wars are mainly staged in terms of quantity. You might have even been thinking that those mini-males look pretty cute, but what if I told you that their testes-to-body-size ratio is four times as large as the dominant males’? When you only have one second to stage your attack, you want to make sure you’ve got plenty of ammo: sneaker males inundate their targets with a barrage of gametes to rival their opponents’. The open battlefield of the aquatic environment means that males are rarely pitted one-on-one against each other, but this all changes when it comes to species that internally fertilize.

Introducing, the weaponized world of the dragonfly (literally). Male dragonflies possess an array of elegant weaponry varied in form and style, but you’ll never see a dragonfly casually toting the trident of Zeus: their weapons are subtly stored, and are for the express purpose of scouring away the sperm of other males. Specially shaped penises featuring scraping appendages are used to deftly remove sperm from previous matings before a male’s own sperm is transferred to the female.

Examples of dragonfly penis morphology; illustration by Sarah Nason, adapted from Córdoba-Aguilar et al. 2003: Sperm competition in Odonata (Insecta): the evolution of female sperm storage and rivals’ sperm displacement.

Because they are able to manually displace the sperm of their opponents, dragonflies are able to avoid any real kind of sperm face-off. But in the event that sperm from two different males are in the same female’s reproductive tract at the same time (in fact, a common scenario), this is where it really goes down: the individual sperm, or spermatozoa, are built for the race. In more competitive environments, sperm can develop ultra-long tails or invest in more energy-producing structures in order to increase their velocity. While we’ve known for a long time that speed determines which particular spermatozoid reaches the egg, competition becomes exponentially fiercer when it’s the sperm of two different males facing off.

Through a combination of sneaky behavioral strategies and superior sperm, evolutionary biologists suspect that the apparent “bachelors” roaming the animal kingdom actually probably have a heck ton of game. So next time you see a photo of a majestic lion, ruler of the savannah, master of his kingdom? Just sayin’, he’s probably compensating for something.

Ladybugs.

If you like having sex, you should thank pathogens for making it possible

The arms race between pathogens and the organisms they infect may be the fundamental reason why animals have taken to having sex and then stuck with it, a new paper reports.

So why do we have sex? Well, it’s obvious isn’t it — we do it to make more humans. But there is a small chink in that explanation, something which has been bothering evolutionary geneticists for about as long there have been any around: sexual reproduction is hard work, whereas asexual reproduction is easy and much more efficient — so why bother with it?

Ladybugs.

Image via Pixabay.

That’s something we’ve all asked ourselves at one point or another but Dr. Jack da Silva and James Galbraith from the University of Adelaide have actually set out to get an answer. After using a computer model to simulate how the genomes of Caenorhabditis elegans (non-parasitic roundworms) shift throughout several generations, the duo suggests that sexual reproduction imposed itself because organisms needed to constantly adapt their genomes to fight off co-evolving pathogens.

“Asexual reproduction, such as laying unfertilised eggs or budding off a piece of yourself, is a much simpler way of reproducing,” says Dr da Silva, Senior Lecturer in the University of Adelaide’s School of Biological Sciences.

“It doesn’t require finding a mate, and the time and energy involved in that, nor the intricate and complicated genetics that come into play with sexual reproduction. It’s hard to understand why sex evolved at all.”

One decades-old theory has been attracting more attention recently, da Silva said. Known as the Hill-Robertson Interference, it holds that sexual reproduction evolved because it allows DNA recombination between mates, allowing offspring to ‘hoard’ more beneficial mutations. In the case of asexual reproduction, where there is no pooling of genes, beneficial mutations compete with each other and natural selection grinds down.

But de Silva says this theory doesn’t explain why sexual reproduction would be maintained in a stable, well-adapted population — where maintaining the status quo makes more evolutionary sense.

 

“It is hard to imagine why this sort of natural selection should be ongoing, which would be required for sex to be favoured,” he says.

“Most mutations in an adapted population will be bad. For a mutation to be good for you, the environment needs to be changing fairly rapidly. There would need to be some strong ongoing selective force for sex to be favoured over asexual reproduction.”

The team’s suggestion is to bring another, less influential evolutionary theory into the mix. Known as the Red Queen theory, it holds that because bacteria, viruses, or parasites are continuously trying to adapt and overcome our natural or artificial defenses, our genomes are also trying to keep one step ahead by continuously mutating, becoming more resistant to them.

‘Good enough’ is better than ‘the best’

While we may be really well adapted to our environments, there’s a constant sort of biological arms race going on. Staying unpredictable — by having the ability to develop new mutations and pool them in offspring — thus becomes more advantageous than reaching a hypothetical ‘best-adapted’ genome and keeping with it.

So in the end, organisms may have chosen sexual reproduction over cloning because, although it’s harder and (on those lonely Saturday nights) more frustrating to pull off, it keeps us all similar but different enough so the germs can’t get us all in one shot. Which I feel is win for us.

“These two theories have been pushed around and analysed independently but we’ve brought them together,” says Dr da Silva. “Either on their own can’t explain sex, but looking at them together we’ve shown that the Red Queen dynamics of co-evolving pathogens produces that changing environment that makes sex advantageous through the simple genetic mechanism of the Hill-Robertson theory.”

“This is not a definitive test but it shows our model is consistent with the best experimental evidence that exists.”

The paper “Hill-Robertson Interference Maintained by Red Queen Dynamics Favours the Evolution of Sex” has been published in the Journal of Evolutionary Biology.

A unisexual female salamander. Credit: Robert Denton.

When you don’t need sex, like these salamanders, you get lazy. And that’s a problem in the face of climate change

A unisexual female salamander. Credit: Robert Denton.

A unisexual female salamander. Credit: Robert Denton.

Mole salamanders are stout-bodied salamanders endemic to North America which are fascinating for a variety of reason. For one, their short stubby arms and little faces with protruding cartoonish eyes makes them some of the cutest amphibians you’ll see. They’re also facultatively paedomorphic, meaning that they may retain larval characteristics as adults and continue to live in the water or metamorphosis and lead a terrestrial life. In other words, these Peter Pans can choose whether or not to become adults. And it gets weirder.

Sex: more than meets the eye

One mole salamander variety is comprised of all females which reproduce asexually by cloning. This strategy seems successful given the unisexual mole salamanders have been around for six million years but one recent study suggests these adorable critters might be at a disadvantage compared to their sex-driven cousins in the face of climate change. Simply put, not having sex makes them lazier, the study seems to conclude.

In Europe, an invasive pathogenic fungus (Batrachochytrium salamandrivorans; Bsal) is wreaking havoc for the salamander and newt biodiversity. In 2016, the U.S. federal government embargoed 201 species to keep amphibians potentially infected with the skin-eating diseases from starting an outbreak at the other end of the pond as well. Despite these best efforts, the fungus might end up infecting North American species. Moreover, climate change and habitat fragmentations make amphibian populations in the U.S. even more vulnerable.

Bearing these threats in mind, biologist Rob Denton and colleagues from Ohio State University are studying the various reproduction strategies of mole salamanders to see what are the advantages and disadvantages for each.

“Salamander-specific chytrid (Bsal) fungus is a huge concern here in the United States, because we have such a wonderful hotbed of salamander diversity compared to the rest of the world,” Dentold told The Smithsonian. “Preventing that outbreak from happening here is really important and part of that is understanding the differences on a species level between these animals—how they interact with each other and how they interact with their landscape.”

The unisexual salamanders, known as Ambystoma, do have a “little bit” of sex, to be fair. When the weather is ripe, meaning wet (they love the rain), these females will come in contact with pockets of sperm deposited by males from either of the five known mole salamander species. “Usually that sperm is just used to tell their body, ‘hey, it’s time to make eggs,’” Denton says. “Sometimes that sperm genome actually sneaks into that next generation,” he added. No one knows yet how this happens.

To test whether this cloning evolutionary strategy is more advantageous than the procreating variety, the researchers placed 17 small-mouth salamanders and 21 unisexual individuals on a treadmill. Every three minutes, the salamanders were given a break from their workouts after a researcher would flip them on their backs. The time it took for each salamander to rebound on their feet was recorded. The longer it took, the more tired the salamander was, the researchers reckoned. This experiment revealed that the sexual salamanders could travel four times the distance asexual salamanders could.

The team then left the lab to assess fitness in the wild. Mole salamanders spend all of their early life in shallow poles from which they emerge only after they’ve metamorphosized from their humble tadpole beginnings. Once they become adults, the sexual salamanders will do some soul searching but, ultimately, will return back to their original breeding pools where they were born to lay eggs. It follows that in any given pond you’ll find a similar genetic makeup.

However, some small-mouth salamanders will break the pattern and land in other pools. So Denton and colleagues set up traps in ponds formed by melted snow and using samples collected from captive individuals they mapped the diversity of the pond. This told them how far an individual between ponds and how it compared to the unisexuals.

The results suggest that in the wild small-mouth salamanders travel twice and a half as far as their counterparts, as reported in the journal Functional Ecology

Not having sex has its perks. For instance, the unisexual salamanders go out less and hence the risk of catching an infectious disease, like Bsal, drops. On the flipside, it’s genetic diversity that could help these salamanders if an outbreak occurs. This is how Tasmanian devils were able to rebound in the face of evil facial tumor disease (DFTD), an 100% kill rate disease which wiped out 80 percent of the population. Then there’s climate change which affects habitats and available resources. If their habitat dries up, unisexual mole salamanders might not make it but their sexual counterparts might, simply because they’re less lazy it seems. So there’s more to sex than meets the eye.

“Maybe the best explanation for why sexual salamanders travel so far is because they have to: On a large landscape with few places to breed, the animals that can cross that distance are the ones that survive and reproduce,” Denton said.

“Perhaps the more interesting question is why the all-female salamanders don’t go very far, and we think that has to do with the physiological costs of not having sex. Essentially, not mixing up your genomic material often enough likely causes some problems for genes that you need to make energy.”

Microbrachius dicki fossils are very common, yet nobody noticed these vertebrates bore differentiated sexual organs. Photo: ROGER JONES

Ancient 385-million-year old Fish pioneered Sex

Paleontologists have identified the first known animals that used internal fertilization instead of spawning – armor-coated swimmers, called antiarchs, which lived around 385 million years ago in lakes in what is now Scotland. The discovery is truly monumental since its the earliest known example of sexual dimorphism or differences in appearance between the sexes in the fossil record.

Sex emerged in a Scottish lake

Microbrachius dicki fossils are  very common, yet nobody noticed these vertebrates bore differentiated sexual organs. Photo: ROGER JONES

Microbrachius dicki fossils are very common, yet nobody noticed these vertebrates bore differentiated sexual organs. Photo: ROGER JONES

Flinders University paleontologist John Long and colleagues were also involved in the discovery of another ancient creature capable of self fertilization; a 380-million-year-old fish they named Materpiscis (“Mother Fish”) that carried embryos inside its body. After studying related fish belonging to a greater group called placoderms, the team found specialized male claspers, which function like a penis, and female genital plates that the fish used to copulate. This latest discovery, a type of placoderm called an antiarch and named Microbrachius dicki, puts vertebrate sex evolution even a step downward.

“We have defined the very point in evolution where the origin of internal fertilisation in all animals began,” Long said.

[ALSO READ] Males may be wired to choose Sex over Food

“That is a really big step.”

Artist impression of an antiarch couple mating. Researchers believe the two had to sit side by side to copulate.

Artist impression of an antiarch couple mating. Researchers believe the two had to sit side by side to copulate.

Long was startled at first by a peculiar isolated plate with a strange tube of bone attached to the rear of a M. dicki fossil specimen. He later realized he was looking at a clasper, which contains grooves that facilitate sperm transfer into the female. After studying other specimens from collections all over the world, Long and team also discovered the female equivalent –  small bony structure at their rear that locked the male organ into place. Early sex was no easy task, however. The strange genitalia geometry means the antiarchs mated sideways, as reported in the journal Nature.

“They couldn’t have done it in a ‘missionary position’,” said Prof Long. “The very first act of copulation was done sideways, square-dance style.”

“The little arms are very useful to link the male and female together, so the male can get this large L-shaped sexual organ into position to dock with the female’s genital plates, which are very rough like cheese graters.

“They act like Velcro, locking the male organ into position to transfer sperm.”

What’s weird is that antiarchs have been studied for well over a century, but it’s only recently that this highly important observation was made. Everybody kept assuming that the ancient fish reproduced in another manner, but evidence speaking otherwise was right there under their noses all the time. Another important insight is that the antiarch’s internal fertilization didn’t last for too long. As fish evolved, they reverted back to spawning, in which eggs and sperm to fertilise them are released into the water by female and male creatures respectively. It took another couple of millions of years before copulation made a come-back, reappearing in ancestors of sharks and rays.

This method of reproduction didn't last very long. Fish soon reverted to spawning.

This method of reproduction didn’t last very long. Fish soon reverted to spawning.

Not everything’s about sex, though. These ancient armored fish were also among the first to evolve important bodily components like  jaws, teeth, paired limbs, and internal fertilization, which we can see to this day. It’s enough to notice your body. Yes, in some weird way, you’re the product of fish sex. Congratulations!

 

Cricket virus acts like an aphrodisiac, but effectively castrates its hosts

cricket

The characteristic “chirp” a cricket makes is created when the insects rub their legs, in an attempt to draw the attention of any nearby female. If he is successful and finds an interested counterpart, the couple quickly gets down to business. Interestingly enough, it’s the female that mounts the male, but that’s less important here; what is important is the devastating virus that affects cricket populations – acting like an aphrodisiac, but rendering its hosts infertile.

The virus, known as IIV-6/CrIV spreads through sexual contact, so it has everything to benefit from cricket copulation. However, as researchers showed, the virus actually caused the sexual contact in the first place! It’s a brilliant bit of behavior manipulation, but not unique; several viruses alter the behavior of the host in order to improve their chances of survival and replication – and it’s not only viruses that do this. Hairworms turn their grasshopper hosts into suicide jumpers so they can get to water while some wasps force spiders to build weird webs to support their cocoons.

Biologist Shelley Adamo noticed something was strange with some of the crickets she kept at the Dalhousie University in Nova Scotia stopped laying eggs. She dissected some of them and found that their reproductive organs had turned blue and were severely bloated – clearly something was awry. She continued her studies and with the help of a microscope found that  the organs were full of hexagonal viral particles that had packed themselves into a crystalline shape, especially the so-called “fat bodies” – an organ that stores fats and produces proteins for the immune system. This was the best place for the virus to infect, because it could affect the communication between the immune system and the nervous system, as well as alter the host’s behavior.

For the virus, the advantage of encouraging promiscuous behavior is easy to understand – but what about the castration? What does the virus have to win by making its hosts sterile?  This kind of “parasitic castration” can help viruses and parasites secure more of the host’s bodily resources for themselves without killing or effectively hurting their hosts.

But the virus has even more tricks up its sleeve. Most notably, it keeps them in good enough shape to attract a mate. Animals that are sick aren’t usually in the mood for mating. They don’t feel so good, they often lose body weight, their temperature might get higher, and so on. But even if they do try to mate, their potential partners often pick up on these cues and avoid them. That would spell disaster for a sexually transmitted disease – but the crickets with IIV-6/CrIV didn’t show any of these “sickness behaviors”. This could only mean one thing: the virus is blocking the fat body from producing signals which would be picked up by the immune system. This is one tricky virus!

At the moment, Adamo isn’t really sure how the virus does all this, but more research will follow, and the underlying mechanisms will be revealed.

To me, the way the virus managed to evolve in order to make all these changes in its host is simply remarkable – and yet another testimony of how powerful viruses can really be.

Scientific Reference.

 

 

 

Sea Slug boasts disposable penis

Well we all use disposable tissues, dishes, I’ve heard of disposable tails of even limbs, but a disposable penis? Talk about taking things to the next level… But that’s exactly what this sea slug has. After mating, it simply discards its penis, grows a new one, and can even have sex again the same day.

sea slug

Chromodoris reticulata, is a type of soft-bodied marine mollusk, and as for the penis disposing process, researchers explain that it simply just falls off. Lead author Ayami Sekizawa from the Osaka City University and his team watched the species copulate 31 times and found that the animals are “simultaneous hermaphrodites” – meaning that both members are both the “man” and the “woman”, impregnating each other.

A typical mating episode involves two individuals touching each other with their genital orifices, then starting the copulation. After a while, one of them backs off, then the other backs off, then they walk for a while with elongated penises, and then the genitalia just sever from their bodies and float away.

“The sea slug sheds 1/3 of the internal penis length after each copulation,” Sekizawa said. “The sea slug is able to grow the penis gradually to its original length.”

But this loss doesn’t seem to hamper the sea slug’s life:

“In one case,” the researchers wrote, “we observed three successive copulations each separated by approximately 24 hours.”

There still isn’t a good explanation for why this happens, but there are a handful of other animals that exhibit a similar behavior. Argonauta, a type of octopus and some orb-weaving spiders have the same type of behavior.

“Little is known about mating behavior in simultaneously hermaphroditic animals,” Sekizawa said. “The disposable penis in our nudibranch (sea slug) study is merely one case of peculiar mating behavior” in these animals.”

Heh, and here I was thinking that squirrels who masturbate to avoid STDs were weird.