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It always boggles me how something like this evolves. Isn’t there a very long period (tens or hundreds of thousands of years) where it doesn’t look like the hos
by doitLP 3y ago
It always boggles me how something like this evolves. Isn’t there a very long period (tens or hundreds of thousands of years) where it doesn’t look like the host termites at all? What selective pressures keep it evolving until it looks exactly like the host species?
Also why would rove beetles be better at this than others, like the army ant example? Do they just have an extra-evolutionary ability to mimic?
- j_m_b 3y agoEvolution can happen rapidly[1]. All the needed changes could have occurred over just a few generations. It likely starts with chemical mimicry. I can't imagine that it didn't start this way as insects live in an umwelt dominated by chemical sensory input. The beetle is able to easily visit the nest, grab food and not be attacked. Their life cycle becomes more and more intertwined with the termites until they never leave the nest. The beetles whole body starts to transform under evolutionary pressures to produce an additional tactile mimicry. That's my just-so story of how it could happen. [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7818422/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7818422/
- bentcorner 3y agoIt also probably works both ways - the termites evolve to better detect parasites, so simple mimicry that worked thousands of years ago wouldn't work today. Similar to the relationship of AV and malware.
- satvikpendem 3y agoOr how GANs work, two networks competing between the generator and the discriminator.
- astrange 3y agoYou can also evolve the ability to evolve rapidly, eg by having areas of "configuration" genes and then "code" genes with more error correction.
- gus_massa 3y agoIt's not exactly what you described, but there are a few weird things. For example microsatelites https://en.wikipedia.org/wiki/Microsatellite https://en.wikipedia.org/wiki/Microsatellite that are small repeated regions in genes, that are difficult to copy, so they have a bigger mutation rate. They can function as tweaking knots when you consider times that involve many generations.
- thaumasiotes 3y ago> It also probably works both ways - the termites evolve to better detect parasites, so simple mimicry that worked thousands of years ago wouldn't work today. This might or might not be true. Birds are a good example - they are subject to parasitic mimicry. One problem that a bird might have is that another bird lays one or more eggs in the first bird's nest. Theoretically, the victim bird will then incubate the egg and potentially feed and rear the nestling as if that nestling were the bird's own child. There are several points in this process where the victim has the opportunity to defend itself: - Ducks (at least some kinds) recognize the threat that another duck will lay an egg in their nest, and will fight approaching ducks to prevent them from doing this. But once the parasitic duck manages to get an egg into a victim's nest, the victim is not able to detect the foreign egg, and is stuck incubating and raising the adoptive duckling. - Some birds learn to recognize their own eggs. If they come home and find a foreign egg in their nest, they will dump that egg onto the ground. - Birds could theoretically be able to recognize nestlings of their own species. This would not help the ducks from the first example, who are victimized by their own kind. But it would help birds to defend themselves against cuckoos (and similar parasites), who lay their eggs in the nests of other species of bird. I am not aware that any species of bird has actually developed this defense, though I wouldn't be surprised if some have. Anyway, what's relevant here is that all of these defenses have failed to develop in large numbers of birds that are subject to the relevant pressures. It's definitely possible that the same simple mimicry that worked 100,000 years ago works just as well today. But it's also possible that there's been an arms race.
- mojo74 3y ago> Some birds learn to recognize their own eggs. If they come home and find a foreign egg in their nest, they will dump that egg onto the ground. It can also works the other way round. Remove an albatross chick from its nest and the parent doesn't recognise them and the chick will starve https://www.dailymail.co.uk/news/article-7619547/Fans-Sir-David-Attenborough-left-tears-baby-Albatross-weathers-70mph-storm.html https://www.dailymail.co.uk/news/article-7619547/Fans-Sir-Da... Nature eh? (Apologies for the Daily Mail link)
- zzbzq 3y ago
- EGreg 3y agoSomething really makes me question all just-so stories. It’s not science. It paints a target around an arrow, the arrow being that all speciation must occur through random mutation and natural selection. Basically, the theory is unfalsifiable. It violates what Karl Popper was talking about. Now, don’t get me wrong. The theory of common descent is falsifiable. The phylogenic tree can be discerned. But the idea that we have discovered all the mechanisms by which speciation (or “macroevolution”) has ever occurred despite never having seen any of them in practice, is in my opinion bad science. And just-so stories are almost self-admitting that it’s more folklore than science. If you think I’m being too heterodox with my opinions, consider the just-so stories in the field of evolutionary psychology and extrapolate to all the phenotypes that are being described. But actually it seems worse than that because the math doesn’t seem to work out. What evolutionary advantage does a wing give before you can even glide? In the generations where it doesn’t accomplish much, it would seem that a random mutation would be far mord likely to disappear than take over a population. A mutation like proto—wings is likely to be extremely rare while the individuals’ genetic fitness may have increased by say 10%, although that is extremely generous considering the proto-wing confers no advantage and might be seen as freaky and unusual by the mates in the intermediate state. But even with an increase in genetic fitness, it is a tiny tiny effect. For it to take over the entire population eventually, or create a major branch within the population that has some “Lamarckian” direction towards a fully-working wing, seems extremely far-fetched.
- jakear 3y ago[flagged]
- koliber 3y agoThe word "falsifiable" does not mean the thing that you are using it for. It sounds like you are using it to mean "it was proven wrong." When talking about theories, a theory that is not falsifiable is one that could not be ever proven wrong. The best theories are falsifiable, but have a lot of evidence pointing for the theory, and little or no against it.
- 3y ago
- gorkish 3y agoThank you for “umwelt”.
- qup 3y agoSeconded, have never run across that word in all my reading.
- jibal 3y agoHere's where I encountered it: https://www.npr.org/2022/06/21/1105793891/ed-yong-an-immense-world-animal-senses https://www.npr.org/2022/06/21/1105793891/ed-yong-an-immense...
- qup 3y agoThanks! > Made famous by zoologist Jakob von Uexkull in 1909, the term Umwelt refers to the perceptual world experienced by each animal, a highly specific kind of "sensory bubble." When we walk our dog and she stops to smell every other bush or car tire, she's taking in through her acutely sensitive nose smells that we take in faintly or not at all. That's because humans and dogs have two different sensory bubbles, or Umwelten. Umwelten! <3
- jabiko 3y agoAs a German speaker it felt really weird reading it. Like your brain is in English mode, reads over the word, then backtracks, switches to German, reads it again and then continues with English.
- huijzer 3y agoI have a lot of appreciation for some specialized German words, such as Fingerspitzengefühl, Wanderlust, Zeitgeist, or Schadenfreude, but why Umwelt? It can just be translated to environment.
- james-bcn 3y agoit is the environment _as experienced_ by an organism. Me and my dog can have the same environment, but we'll have different umwelt, because mine is primarily visual but his has a much larger scent component.
- yieldcrv 3y agoI’m willing to entertain a dash of Spontaneous Generation alongside selective pressures
- intrasight 3y agoGod having fun with Blender
- phito 3y agoEvolution is much smarter than just random mutations
- lusus_naturae 3y agoEvolution is a population level effect and doesn't have a plan or scheme, it's whatever helps reproduction.
- phito 3y agoIt doesn't stop it from being smart at solving problems.
- SteveNuts 3y agoIsn't it just random?
- lusus_naturae 3y agoBut that's the point though, it's not trying to solve anything. The biological impetus to survive is individual, and we see some emergent property of survival instincts in the development and existence of groups, societies, culture, etc. In non-human animals, there are lots of example of cooperation and symbiosis. All this to say that problem solving is a biological problem, not an evolutionary problem. There are pressures that favor some traits over others, and then we have population level effects, but the development of traits is inherently random.
- jcims 3y agoI’ve always had a notion that there’s some kind of gene theft with mimicry. The combinatorics of just rattling genes into existence that build a mock termite larva seem infeasible in the timescale involved. What does the math look like? How many possible gene configurations are there that will build a mock termite on the back of a beetle? What’s the shortest random walk to get there from a beetle with no termite on its back and how does that compare with the total number of these beetles ever created in nature? A single gene might have 4^300 configurations. Are there five genes or fifty or five hundred involved? How many of these beetles have ever been built? 10^20?
- shellfishgene 3y agoAs development works in stages based on the last one, I would assume gene theft just doesn't work on a beetle genome background. You would have to change development from the egg onwards to mimic the termite, essentially turning the beetle into a termite proper.
- phito 3y agoThe genome does not store a map of the final organism, so it seems unlikely.
- legulere 3y agoIt’s not just the beetle that evolved but the termites as well. It probably started out with the termites being pretty bad at detecting their kind and becoming progressively better because of the pressure of that beetle stealing their food.
- slavetologic 3y agoI don't believe that evolution is a random walk. There's clearly momentum based factors
- mjan22640 3y agoSince the discovery of DNA we build up the common knowledge that "it is all in the DNA", and the basis of evolution is a random change in DNA. It was due to a selection bias, DNA is a static structure that sits there and waits to be studied while the nano processes in a cell were impenetrable until fairly recently. DNA only contains templates for proteins. It does not contain informtion how to assemble the molecular machines from the proteins, or how "to be alive" in general. A cell is a fairly intelligent problem solver, that can adapt and chang during its lifetime, it does not need to wait for a mutation to occur. There is heritable information outside of DNA, that is epigenetic in its nature. In a multicellular organism this information is communicated and shared between cells. A beneficial DNA mutation is like a lottery win. It might be viable strategy in viruses an bacteria, who divide at an astronomical speed. A multicellular organism gametes divide only a handfull of times per generation. These need to put a more concerted effort, than a random chance, to score.
- ampdepolymerase 3y agoNo, no, no. Explanation is inaccurate. The central dogma is the central dogma because information flow is primarily one way (yes there are exceptions i.e. epigenetics but primary information flow is from DNA to protein) and this is the fundamental tenet underpinning our current understanding of biology. > A multicellular organism gametes divide only a handfull of times per generation. That's what recombination is for during sexual reproduction. > It does not contain informtion how to assemble the molecular machines from the proteins, or how "to be alive" in general. Unless you subscribe to the creationist or Larmarckian schools of thought, this is flat out wrong. DNA polymerase and similar analogues like reverse transcriptase do not exist in a vacuum. There are entire branches of evolutionary biology dedicated to studying their formation. The main transcription proteins, helicase, polymerase, and ribosomes can all be assembled from the basic proteins they themselves transcribe. (Incidentally figuring out the ultimate structure that a protein chain assembles into is what AlphaFold does, bioinformatics and ML's crowning jewel) > There is heritable information outside of DNA, that is epigenetic in its nature. When biologists refer to epigenetics, they mean information carriage that's not strictly tied to the nucleotides. This doesn't meant DNA isn't involved. Most epigenetics I can think of off the top of my head all involve the DNA transcription mechanism in some way.
- tomcam 3y agoAll the answers you got are fairly state of the art, but it’s mostly descriptive. Very little testable or otherwise falsiable information. The more we learn about developmental biology the more baffling the origin of cellular behavior becomes.
- hyperthesis 3y agoIt needn't be perfect at first, just better than nothing (fool some of the eyes, some of the time e.g. in low-light conditions) and a gradient. See Richard Dawkins' chapter "Do good by Stealth" in River Out of Eden https://wikipedia.org/wiki/River_Out_of_Eden#Do_good_by_stealth https://wikipedia.org/wiki/River_Out_of_Eden#Do_good_by_stea...
- shellfishgene 3y agoJust imagine the first rove beetle was adapted to be a predator of social insects. It runs to the colony and tries to grab some eggs. It's often detected and killed. So maybe by chance one beetle has a mutation that makes one of its pherhormones (or whatever) smell slightly more like termite. It's a bit less likely to get killed by the termites, so it has an advantage and higher reproductive success. The new genes spreads through the population. The another one gets a mutation that makes it's antennae just a bit more termite-like... You get the idea. Why rove beetles? No idea, but maybe their body plan was for some reason more adaptible to change morphology? Also maybe because they were closely associated to colonial insects from the beginning as predators, and so had high selective pressure to avoid detection.
- yalogin 3y agoI have the same questions, more so because if it happens over a long time it’s not sustainable. The beetle population can be in some weird in-between state which could be tough for their survival.
- gus_massa 3y agoTotally unsupported hypothesis: They evolved first a big fat termite ass, that is much easier and it's probably good enough many times in the dark narrow alleys of a termite hive. Later they evolved the decoration. It would be nice to see how the beetle grows, because "Ontogeny recapitulates phylogeny" is not exact, but sometimes is a good approximation.
- ajuc 3y agoThere's no incentive for termites to be good at distinguishing impostors before there are impostors. So they could get away with very bad disguise at first, then arms race started.
- HelloNurse 3y agoThere's also the separate evolutionary axis of how the beetle behaves: they learned to seek out termites and collect food from them, exposing themselves to quick lynching if the disguise fails. It's easy to imagine intermediate states where mediocre disguises work some of the time and the beetle is cautious because it occasionally needs to run away.
- melagonster 3y agoactually this is a cool question, biologists always try to reply these questions. but this is a new species...