Heh, for a second there this read like some of the Portiid adventures with Bianca and Fabian from Adrian Tchaikovsky's book "Children of time". If you find this kind of thing interesting and are a fan of sci-fi, I highly recommend the book.
It is truly fascinating, I wonder how it evolved like that.
Before becoming a spring as it is today how was it hunting in the past? What constraints made it need such a mechanism instead of a typical web?
Amazing specialization. I was wondering the same thing. Cave glow worms cast a "fishing line," and this is similar-ish. I wonder if N million years ago, a couple of fishing-line-like spiders started anchoring their lines, and the ones with a more conic shape anchor may led to more success over time. And the anchor may have only worked on territorial prey. Fun stuff to imagine.
Me too! I was visiting my parents’ farm and walking around in pitch black while looking at the stars when I saw a bright green glow out of the corner of my eye. Ended up tracking it down to a California pink glow worm that had perched itself on a rock.
Injured Himenoptera are known to send pheromones that trigger a vicious defensive response from other members of the colony. On a typical web the companion ants would do what the ants do. Go to war and flood the place surrounding the danger until eventually killing it. The spider does not have neither the stamina, nor the venom amount to deal with that. This web is designed to extract just one ant, while cutting the path that the ant rescuers could follow.
This is the first spider web known designed to catch only one species of prey. That alone would make the finding extraordinary. The trap can lure only green ants and serve the food exactly were the spider wants it; granting access to a common source of food that is everywhere, but also that is very dangerous to hunt (as much big as the spider, with powerful jaws, and much stronger).
The video shows one most interesting thing: Notice that the spider is carefully moving out of the way, just a second before the ant is launched. The spider knows in advance that its current location is about to be hit by a bungee jumping ant, and acts accordingly just in time to avoid the "bullet". We can easily imagine the spider thinking 5,4,3... This means that spider brains can predict the future outcome of a complex movement of objects in the physical system of its trap, and also calculate how much time the fibers will resist the jaw of the ant.
The smart spider is portia, a jumping spider. A quick search uncovers zounds of videos, articles, and scientific publications on them.
They specialize is hunting spiders, changing hunting tactics based on type and number of prey. Yes, they count. They strategize. They make multi-step plans that take them out of sight of prey. And some people keep them as pets.
I can personally vouch for them being great pets. They're active during the day, hunt prey, don't need much food or water, and tend to "hide" in silk cases they build along the top of their terrariums so you can always see them. They like to get water from inside flowers, and probably can differentiate between many colors, so adding bright flowers not only makes things prettier, it provides a watering hole and possible hunting advantage over color-blind insects trying to hide.
Of course, if you don't want to set up a terrarium and personally sentence crickets to death, just look at the screens in your windows. Odds are, a jumping spider is already living there and will stay as long as you let it. They're territorial.
> Notice that the spider is carefully moving out of the way, just a second before the ant is launched.
It's not moving before the ant is launched. It's moving as soon as the tension in the web is gone, ie. there's movement in their web. Most spiders react to movement in their web.
There are many such mysterious mysteries in evolution. Some wasps paralyse a caterpillar of a particular species by stinging it very precisely in its nervous centres, then carries the caterpillar into the nest it previously dug out, lay its egg on the caterpillar then close the hole to never come back.
This is a completely automatic, unintelligent behaviour; if you remove the paralysed caterpillar at any point in the process the wasp simply goes on with its business (it will close its nest without any caterpillar inside, where the larva will die out from lack of food).
In the late 19th century, Jean-Henri Fabre studied these wasps (and many other strange insects) and had a copious correspondence with Charles Darwin on this very matter. His books are absolutely fascinating (ditto the letters Darwin and him exchanged).
The weirdest insects I've seen in real life are these ones called Burying Beetles - they have chemoreceptors that allow them to detect the odor of a dead mouse from as far away as two miles. Then a male and female fly to it, dig a big hole, strip all the fur off of it to line the hole, then drag it down in there and raise their young together. They are also unusual in that outside of bees and ants, very few insects raise their young together from infancy to adulthood.
2° it paralyses a caterpillar (some other species use different worms, or beetles, as their victims; but each species of wasp targets one precise species of caterpillar or bug and cannot use any other food source for its larvae than the one it's genetically programmed to catch).
3° it carries the caterpillar into the hole
4° it lays its egg on the caterpillar, far from the head
5° it closes the hole with dirt
6° the egg hatches in the dark, and the larva feasts on the paralysed caterpillar, eating it alive.
If you pull out the caterpillar while the wasp turns around to lay its egg, it doesn't interrupt itself. IIRC even if you take the caterpillar while it's flying to the hole, it still proceeds to the end, without the caterpillar (which makes no sense at all, showing it's a purely reflex activity, without any intelligence).
I'm from where these spiders were found. The ants they're predating are an equally fascinating and super aggressive species of green weaver ants (that have other cool predators like "mimic" jumping spiders).
As a general rule of dynamical systems, specialization is essentially the exploitation of regularity within your environment.
A highly regular environment can allow for extreme specialization because a system can predict and "expect" certain situations. This leads to much less energy expended, since maintaining stability requires energy that scales with the turbulence of a system.
If gravity is always down, you don't need to spend energy on organs that overcome gravity in other directions. Your circulatory system can use gravity to its advantage; that's why you can't just remain upside down, there's no effective mechanism to pump blood out of your brain.
If a car passes a street exactly every 2 minutes, you don't need to spend lots of time and energy figuring out when to cross. You know once a car crosses, you're good for 2 minutes. If you know the sun comes up around the same time every day, you can allow yourself a deep sleep during the night if you're in a safe place, or bloom only during the day.
Nature exploits such regularities in order to reduce the energy needed to maintain an organism or group, which creates specialization, whether on the scale of the group, on the scale of the individual, etc. This is hierarchical; your cells specialize, your organs specialize, you get training or education to specialize your skills, etc. For example, you might specialize as a software engineer, depending on the regularity of people willing to pay money for you to solve their problems, but AI comes around and suddenly you're out of a job.
The danger is that the more regularities you depend on, the less free energy your body needs to keep around and the less free energy you have to suddenly react and adapt to a new environment. If tomorrow, gravity started being up and not down, most of us would have a bad time. If those regularities are interdependent, as geological/biological cycles tend to be, a few bad conditions could unravel the entire ecosystem.
fascinating and thank you for the great explanation. I was actually going to followup and ask with regards to AI but your response covered it aswell :)
I wonder why biological organisms are capable of such absurdly high accelerations. Article reminded me of cnidocytes which apparently produce anywhere between 40,000 and 5,410,000 g. Is it because of the small masses involved?
If they would prove that the trap also breaks the ant neck, saving venom, or stunning the prey for easy kill, that would be incredible. Somebody needs to include this thing in the script of a science fiction film.
The part from the paper which is so interesting is why the ant bites the trap in the first place. The paper suggests that the spider puts out a pheromone that attracts the ant and triggers the ant to aggressively bite the snare, but the pheromone only does this for the spider's target species, the green tree ant. The researchers watched three other ant species check out the snare, go "meh", and move on, unharmed, without showing any aggression towards the snare.
that's a good question -- the paper describes it triggering aggression in the ant within milliseconds of it probing the snare with its antenna. I don't know the basis for it, but that's some down-to-the-metal ant programming right there
It is the year 2038. A new brand of slingshot is almost immediately removed from store shelves after multiple children receive through-and-through wounds.
The notion of a species only really exists in the human world; it's a human concept. So the discovery of a new species is the discovery of a new classification need. It is new to science.
(At a first approximation, essentially all existing species are new on an evolutionary level — isn't it the case that something like 99.9% of all life on earth is newer than a million years old?)
Not seeing the "problem." To humans, it's new. It's a new addition to the list of "species we know about." It's a new spider species. This is how language has been used for a long time.
This is the first spider web known designed to catch only one species of prey. That alone would make the finding extraordinary. The trap can lure only green ants and serve the food exactly were the spider wants it; granting access to a common source of food that is everywhere, but also that is very dangerous to hunt (as much big as the spider, with powerful jaws, and much stronger).
The video shows one most interesting thing: Notice that the spider is carefully moving out of the way, just a second before the ant is launched. The spider knows in advance that its current location is about to be hit by a bungee jumping ant, and acts accordingly just in time to avoid the "bullet". We can easily imagine the spider thinking 5,4,3... This means that spider brains can predict the future outcome of a complex movement of objects in the physical system of its trap, and also calculate how much time the fibers will resist the jaw of the ant.
They specialize is hunting spiders, changing hunting tactics based on type and number of prey. Yes, they count. They strategize. They make multi-step plans that take them out of sight of prey. And some people keep them as pets.
I can personally vouch for them being great pets. They're active during the day, hunt prey, don't need much food or water, and tend to "hide" in silk cases they build along the top of their terrariums so you can always see them. They like to get water from inside flowers, and probably can differentiate between many colors, so adding bright flowers not only makes things prettier, it provides a watering hole and possible hunting advantage over color-blind insects trying to hide.
Of course, if you don't want to set up a terrarium and personally sentence crickets to death, just look at the screens in your windows. Odds are, a jumping spider is already living there and will stay as long as you let it. They're territorial.
It's not moving before the ant is launched. It's moving as soon as the tension in the web is gone, ie. there's movement in their web. Most spiders react to movement in their web.
This is a completely automatic, unintelligent behaviour; if you remove the paralysed caterpillar at any point in the process the wasp simply goes on with its business (it will close its nest without any caterpillar inside, where the larva will die out from lack of food).
In the late 19th century, Jean-Henri Fabre studied these wasps (and many other strange insects) and had a copious correspondence with Charles Darwin on this very matter. His books are absolutely fascinating (ditto the letters Darwin and him exchanged).
> it will close its nest without any caterpillar inside, where the larva will die out from lack of food
...wouldn't the larva be with the caterpillar? You said that's where it lays the eggs.
1° the wasp digs a hole in soft ground
2° it paralyses a caterpillar (some other species use different worms, or beetles, as their victims; but each species of wasp targets one precise species of caterpillar or bug and cannot use any other food source for its larvae than the one it's genetically programmed to catch).
3° it carries the caterpillar into the hole
4° it lays its egg on the caterpillar, far from the head
5° it closes the hole with dirt
6° the egg hatches in the dark, and the larva feasts on the paralysed caterpillar, eating it alive.
If you pull out the caterpillar while the wasp turns around to lay its egg, it doesn't interrupt itself. IIRC even if you take the caterpillar while it's flying to the hole, it still proceeds to the end, without the caterpillar (which makes no sense at all, showing it's a purely reflex activity, without any intelligence).
Se for instance https://www.gutenberg.org/ebooks/3462
(Jean-Henri Fabre was a marvellous writer, and the English translation is very good).
https://en.wikipedia.org/wiki/Weaver_ant
super interesting. I'm guessing because being highly dependent on a single tactic can make it difficult to adapt or course change ?
A highly regular environment can allow for extreme specialization because a system can predict and "expect" certain situations. This leads to much less energy expended, since maintaining stability requires energy that scales with the turbulence of a system.
If gravity is always down, you don't need to spend energy on organs that overcome gravity in other directions. Your circulatory system can use gravity to its advantage; that's why you can't just remain upside down, there's no effective mechanism to pump blood out of your brain.
If a car passes a street exactly every 2 minutes, you don't need to spend lots of time and energy figuring out when to cross. You know once a car crosses, you're good for 2 minutes. If you know the sun comes up around the same time every day, you can allow yourself a deep sleep during the night if you're in a safe place, or bloom only during the day.
Nature exploits such regularities in order to reduce the energy needed to maintain an organism or group, which creates specialization, whether on the scale of the group, on the scale of the individual, etc. This is hierarchical; your cells specialize, your organs specialize, you get training or education to specialize your skills, etc. For example, you might specialize as a software engineer, depending on the regularity of people willing to pay money for you to solve their problems, but AI comes around and suddenly you're out of a job.
The danger is that the more regularities you depend on, the less free energy your body needs to keep around and the less free energy you have to suddenly react and adapt to a new environment. If tomorrow, gravity started being up and not down, most of us would have a bad time. If those regularities are interdependent, as geological/biological cycles tend to be, a few bad conditions could unravel the entire ecosystem.
"The Fly" is ready for a quick rewrite.
>discovered a remarkable new spider species...
Recently evolved then?
Or perhaps...
"An international team of researchers has recently discovered a remarkable spider species..."
(At a first approximation, essentially all existing species are new on an evolutionary level — isn't it the case that something like 99.9% of all life on earth is newer than a million years old?)