A herd of wildebeests, a shoal of fish, a flock of birds. Many animals gather in large groups that are among the most wonderful spectacles in the natural world. But why do these groups form? The common answers include things like seeking safety in numbers or hunting in packs or gathering to mate or breed, and all of these explanations, while often true, make a huge assumption about animal behavior, that the animals are in control of their own actions, that they are in charge of their bodies. And that is often not the case.
Nje tufe antilopash afrikane, nje cektine me peshq, nje tufe me zogj. Shume kafshe mblidhen ne grupe te medha dhe eshte nje nga spektaklet me te mrekullueshme ne boten natyrore. Por perse formohen keto grupe? Pergjigja me e zakonshme perfshin gjera si jane me te sigurt ne shumice, ose gjuetia ne grupe ose mblidhen per te gjetur partner ose per te ngrene, dhe te gjitha keto shpjegime, nderkohe qe jane shpesh te verteta, bejne nje supozim te madh per sjelljen e kafsheve, qe kafshet jane ne kontroll te veprimeve te tyre, se ato jane ne kontroll te trupit te tyre. Por shpesh nuk eshte kjo ceshtja.
This is Artemia, a brine shrimp. You probably know it better as a sea monkey. It's small, and it typically lives alone, but it can gather in these large red swarms that span for meters, and these form because of a parasite. These shrimp are infected with a tapeworm. A tapeworm is effectively a long, living gut with genitals at one end and a hooked mouth at the other. As a freelance journalist, I sympathize. (Laughter) The tapeworm drains nutrients from Artemia's body, but it also does other things. It castrates them, it changes their color from transparent to bright red, it makes them live longer, and as biologist Nicolas Rode has found, it makes them swim in groups. Why? Because the tapeworm, like many other parasites, has a complicated life cycle involving many different hosts. The shrimp are just one step on its journey. Its ultimate destination is this, the greater flamingo. Only in a flamingo can the tapeworm reproduce, so to get there, it manipulates its shrimp hosts into forming these conspicuous colored swarms that are easier for a flamingo to spot and to devour, and that is the secret of the Artemia swarm. They aren't sociable through their own volition, but because they are being controlled. It's not safety in numbers. It's actually the exact opposite. The tapeworm hijacks their brains and their bodies, turning them into vehicles for getting itself into a flamingo.
Kjo eshte Artemia, nje karkalec i liqeneve te kripura. Ndoshta me mire e njihni si majmuni i detit. Eshte i vogel, dhe eshte tipike te jetoje vetem, por mund te mblidhet ne keto mizeri te medha te kuqe qe zgjatohet per metra, dhe kjo forme ndodh per shkak te nje paraziti. Keto karkaleca jane te infektuar nga nje shirit. Nje shirit eshte nje zorre e gjate e gjalle me gjenitalet ne nje fund dhe koken ne fundin tjeter. Si gazetar freelancer, une e simpatizoj. (Te qeshura) Shiriti i thith perberesit nga trupi i Artemias, por gjithashtu ben edhe gjera te tjera. Ai i tredh ato, ia ndryshon ngjyren nga transparente ne nje te kuqe te ndezur, i ben ato te jetojne me gjate, dhe ashtu sic ka gjetur biologu Nicholas Rode, i ben ato te notojne ne grupe. Perse? Sepse shiriti, ashtu si shume parazite te tjere, ka nje cikel jete te komplikuar qe perfshin mbartes te ndryshem. Karkalecat jane vetem nje hap ne jeten e tij. Destinacioni i tij final eshte, flamingo i madh. Shiriti mund te riprodhohet vetem ne nje flamingo, per te arritur aty, ai duhet te manipuloje karkalecin mbartes qe te formoje keto mizeri te ngjyrosura te dukshme qe jane me te lehta te vihen re nga nje flamingo dhe te gelltiten, dhe ky eshte sekreti i mizerive te Artemias. Ato nuk jane te shoqerueshme me vullnetin e tyre, por sepse ato po kontrollohen. Nuk eshte siguria ne shumice. Eshte ne fakt komplet e kunderta. Shiriti sulmon trurin dhe trupin e tyre, duke i kthyer ato ne mjete per tu futur tek nje flamingo.
And here is another example of a parasitic manipulation. This is a suicidal cricket. This cricket swallowed the larvae of a Gordian worm, or horsehair worm. The worm grew to adult size within it, but it needs to get into water in order to mate, and it does that by releasing proteins that addle the cricket's brain, causing it to behave erratically. When the cricket nears a body of water, such as this swimming pool, it jumps in and drowns, and the worm wriggles out of its suicidal corpse. Crickets are really roomy. Who knew?
Dhe ja ku eshte nje shembull tjeter i manipulimeve te paraziteve. Kjo eshte nje bulkth vetevrases. Ky bulkth gelltiti larven e nje krimbi Gordian, ose krimbi i jeles kalit. Krimbi u rrit ne permasat e tij normale, por atij i nevojitet te shkoje nen uje ne menyre qe te ciftezohet, dhe e ben kete duke leshuar proteina qe e prishin trurin e bulkthit, duke shkaktuar qe ai te sillet ne menyre te parregullt. Ne momentin qe bulkthi i afrohet nje vendi me uje, sic mund te jete nje pishine, hidhet ne te dhe mbytet, nderkohe qe krimbi del jashte nga trupi vetvrases. Bulkthet jane kaq te bollshem. Kush e dinte?
The tapeworm and the Gordian worm are not alone. They are part of an entire cavalcade of mind-controlling parasites, of fungi, viruses, and worms and insects and more that all specialize in subverting and overriding the wills of their hosts. Now, I first learned about this way of life through David Attenborough's "Trials of Life" about 20 years ago, and then later through a wonderful book called "Parasite Rex" by my friend Carl Zimmer. And I've been writing about these creatures ever since. Few topics in biology enthrall me more. It's like the parasites have subverted my own brain. Because after all, they are always compelling and they are delightfully macabre. When you write about parasites, your lexicon swells with phrases like "devoured alive" and "bursts out of its body." (Laughter)
Shiriti dhe krimbi Gordian nuk jane te vetmit. Ata jane pjese e nje vargani te tere te paraziteve manipulues, e kepurdhave, viruseve, dhe krimbave dhe insekteve dhe te tjera qe jane te specializuara ne shkaterrimin dhe mbizoterimin e deshirave te mbartesve te tyre. Fillimisht une kam mesuar per kete menyre jetese nepermjet David Attenborough "Gjykimet e jetes" rreth njezet vjet me pare, dhe me pas nepermjet nje libri te mrekullueshem "Parazitet Rex" nga miku im Carl Zimmer. Dhe qe atehere s'kam pushuar se shkruari per keto krijesa. Pak subjekte ne biologji me magjepsin me shume se ata. Eshte sikur parazitet kane pushtuar trurin tim. Sepse ne fund te fundit, ata jane gjithmone imponues dhe te lezetshem ne menyre makabre. Kur ti shkruan per parazitet, leksiku yt mbushet me fraza si "i gelltit te gjalle" dhe "nxjerr jashte nga trupi." (Te qeshura)
But there's more to it than that. I'm a writer, and fellow writers in the audience will know that we love stories. Parasites invite us to resist the allure of obvious stories. Their world is one of plot twists and unexpected explanations. Why, for example, does this caterpillar start violently thrashing about when another insect gets close to it and those white cocoons that it seems to be standing guard over? Is it maybe protecting its siblings? No. This caterpillar was attacked by a parasitic wasp which laid eggs inside it. The eggs hatched and the young wasps devoured the caterpillar alive before bursting out of its body. See what I mean? Now, the caterpillar didn't die. Some of the wasps seemed to stay behind and controlled it into defending their siblings which are metamorphosing into adults within those cocoons. This caterpillar is a head-banging zombie bodyguard defending the offspring of the creature that killed it.
Por ka me shume gjera se kaq. Une jam shkrimtar, dhe shkrimtaret ne audience e dine se ne i dashurojme historite. Parazitet na ftojne qe ti rezistojme joshjes se historive te dukshme. Bota e tyre eshte nje bote me komplote te gershetuara dhe me shpjegime te papritura. Perse, per shembull, kjo vemje fillon te dridhet me zhurme kur nje insekt tjeter i shkon afer asaj dhe fshikezave te bardha qe duket sikur po u ben roje? Ndoshta per te mbrojtur motrat e saj? Jo. Kjo vemje eshte sulmuar nga nje grerez parazite e cila vendos veze brenda saj. Vezet celen dhe grereza te reja gelltiten vemjet e gjalla perpara se te dilnin nga trupi i tyre. E kuptoni tani? Tani, vemja nuk ngordhi. Disa nga grerezat qendruan prapa dhe e kontrolluan ate ne mposhtjen e motrave te saj gjate metamorfozes se tyre ne te rritur brenda ketyre fshikezave. Keto vemje jane si nje truproje zombie qe mbron pasardhesit e krijeses qe e vrane ate.
(Applause)
(Duartrokitje)
We have a lot to get through. I only have 13 minutes. (Laughter)
Kemi shume gjera per te kaluar. Kam vetem 13 minuta. (Te qeshura)
Now, some of you are probably just desperately clawing for some solace in the idea that these things are oddities of the natural world, that they are outliers, and that point of view is understandable, because by their nature, parasites are quite small and they spend a lot of their time inside the bodies of other things. They're easy to overlook, but that doesn't mean that they aren't important. A few years back, a man called Kevin Lafferty took a group of scientists into three Californian estuaries and they pretty much weighed and dissected and recorded everything they could find, and what they found were parasites in extreme abundance. Especially common were trematodes, tiny worms that specialize in castrating their hosts like this unfortunate snail. Now, a single trematode is tiny, microscopic, but collectively they weighed as much as all the fish in the estuaries and three to nine times more than all the birds. And remember the Gordian worm that I showed you, the cricket thing? One Japanese scientist called Takuya Sato found that in one stream, these things drive so many crickets and grasshoppers into the water that the drowned insects make up some 60 percent of the diet of local trout. Manipulation is not an oddity. It is a critical and common part of the world around us, and scientists have now found hundreds of examples of such manipulators, and more excitingly, they're starting to understand exactly how these creatures control their hosts.
Tani, disa prej jush ndoshta jane duke kerkuar deshperimisht per pak ngushellim qe keto gjera jane kuriozitete te botes natyrore, se ata jane te vecuar, dhe kjo pikpamje eshte e kuptueshme, sepse nga natyra e tyre, parazitet jane shume te vegjel dhe shpenzojne shume kohe te jetes se tyre brenda trupave te gjerave te tjera Ata mund te neglizhohen lehte, por kjo nuk do te thote qe ata jane te parendesishem. Disa vjet me pare, nje njeri i quajtur Kevin Lafferty mori nje grup shkencetaresh ne tre estuaret kaliforniane dhe ata peshuan dhe shqyrtuan dhe regjistruan cdo gje qe mund te gjenin, dhe ajo cfare gjeten ishte nje bollek parazitesh. Vecanerisht te zakonshem ishin trematodet, krimba te vegjel te specializuar ne tredhjen e mbartesve te tyre ashtu si ky kermilli i pafat. Nje trematod e vetme eshte e vogel, mikroskopike, por sebashku ato peshojne kaq shume sa te gjithe peshqit neper laguna dhe tre deri ne nente here me shume se te gjithe zogjte. Dhe e mbani mend krimbin Gordian qe ju tregova, ajo historia e bulkthit? Nje shkencetar japonez i quajtur Takuya Sato gjeti se ne nje rrjedhe keta krimba drejtojne kaq shume bulkthe dhe karkaleca ne uje saqe insektet e mbytur perbejne rreth 60 perqind te dietes se troftave lokale. Manipulimi nuk eshte nje gje e rralle. Eshte pjese kritike dhe e zakonshme e botes rreth nesh, dhe shkencetaret tani kane gjetur me qindra shembuj te manipulimeve te tilla, dhe me shume, ata po fillojne te kuptojne ekzaktesisht sesi keto krijesa kontrollojne prene e tyre.
And this is one of my favorite examples. This is Ampulex compressa, the emerald cockroach wasp, and it is a truth universally acknowledged that an emerald cockroach wasp in possession of some fertilized eggs must be in want of a cockroach. When she finds one, she stabs it with a stinger that is also a sense organ. This discovery came out three weeks ago. She stabs it with a stinger that is a sense organ equipped with small sensory bumps that allow her to feel the distinctive texture of a roach's brain. So like a person blindly rooting about in a bag, she finds the brain, and she injects it with venom into two very specific clusters of neurons. Israeli scientists Frederic Libersat and Ram Gal found that the venom is a very specific chemical weapon. It doesn't kill the roach, nor does it sedate it. The roach could walk away or fly or run if it chose to, but it doesn't choose to, because the venom nixes its motivation to walk, and only that. The wasp basically un-checks the escape-from-danger box in the roach's operating system, allowing her to lead her helpless victim back to her lair by its antennae like a person walking a dog. And once there, she lays an egg on it, egg hatches, devoured alive, bursts out of body, yadda yadda yadda, you know the drill. (Laughter) (Applause)
Kjo ketu eshte nje nga shembujt e mi te preferuar. Kjo eshte Ampulex compresa grereza e smeraldt e kacabunit, dhe njihet boterisht qe nje grereze e smeraldte e kacabunit qe ka disa veze te fertilizuara eshte duke kerkuar nje furrtare. Keshtu qe kur ajo e gjen nje ajo i ngul thumbin asaj qe eshte gjithashtu nje shqise. Ky zbulim doli tre jave me pare. Ajo i ngul thumbin qe eshte nje shqise dhe eshte i pajisur me nje gunge me ndijues qe e lejon ate te ndjeje strukturen e vecante te trurit te furrtares. Ashtu si nje njeri qe germon verberisht ne nje cante ajo gjen trurin, dhe injekton helmin ne dy grupe neurore shume specifike. Shkencetaret izraelit Frederic Libersat dhe Ram Gal gjeten se helmi eshte nje arme kimike shume specifike. Ai as nuk e vret furrtaren, as nuk e qeteson ate. Furrtarja mund te largohet, ose te fluturoje ose te vrapoje nese e zgjedh kete, por nuk e ben kete gje, sepse helmi ia heq motivimin per te ecur, dhe vetem ate. Grereza ia bllokon sinjalin -shpeto nga rreziku-, ne sistemin operues te buburrecit, duke e lejuar ate te drejtoje viktimen e tij te paafte drejt skutes se saj me ane te antenave si nje person qe shetit nje qen. Dhe kur arrin atje, ajo vendos vezet, vezet celin, e gelltisin te gjalle, dalin jashte trupit, yadda yadda yadda, e dini pjesen tjeter. (Te qeshura) (Duartrokitje)
Now I would argue that, once stung, the cockroach isn't a roach anymore. It's more of an extension of the wasp, just like the cricket was an extension of the Gordian worm. These hosts won't get to survive or reproduce. They have as much control over their own fates as my car. Once the parasites get in, the hosts don't get a say.
Duhet t'ju them qe pasi eshte thumbuar, furrtarja nuk eshte me nje buburrec. Eshte me shume nje zgjatim i grerezez, ashtu si bulkthi qe ishte nje zgjatim i krimbit Gordian. Keto mbartes nuk do te arrijne te mbijetojne apo te riprodhohen. Ata kane aq shume kontroll ndaj fatit te tyre sa ka makina ime. Mbasi paraziti futet brenda, mbartesi nuk mund te vendose me.
Now humans, of course, are no stranger to manipulation. We take drugs to shift the chemistries of our brains and to change our moods, and what are arguments or advertising or big ideas if not an attempt to influence someone else's mind? But our attempts at doing this are crude and blundering compared to the fine-grained specificity of the parasites. Don Draper only wishes he was as elegant and precise as the emerald cockroach wasp. Now, I think this is part of what makes parasites so sinister and so compelling. We place such a premium on our free will and our independence that the prospect of losing those qualities to forces unseen informs many of our deepest societal fears. Orwellian dystopias and shadowy cabals and mind-controlling supervillains -- these are tropes that fill our darkest fiction, but in nature, they happen all the time.
Tani njerezit, sigurisht, nuk jane te panjohur ndaj manipulimit. Ne marrim droga per te ndryshuar kimine e trurit tone dhe per te ndryshuar humorin tone dhe c'jane debatet, reklamat apo idete e medha nese jo nje perpjekje per te influencuar ne mendjen e dikujt tjeter? Por perpjekjet tona per te bere kete jane te paperpunuara dhe me shume gabime krahasuar me specifikimin me shume finese te paraziteve. Sikur te ishte Don Draper i Mad Man aq elegant dhe preciz sa grereza e smeraldt e buburrecit. Une mendoj se kjo eshte pjese e asaj qe i ben parazitet kaq te keqinj dhe kaq te parrezistueshem. Ne i japim kaq shume rendesi vullnetit tone te lire dhe pavaresise sone saqe perspektiva e humbjes se ketyre karakteristikave ndaj forcave te padukshme na ve ne dukje friket tona sociale me te medha. Distopite ornuelliane dhe konspiruesit dhe kriminelet qe kontrollojne mendjet- keto jane kuptimet figurative te sajimeve me te frikshme por ne natyre, kjo ndodh gjate gjithe kohes.
Which leads me to an obvious and disquieting question: Are there dark, sinister parasites that are influencing our behavior without us knowing about it, besides the NSA? If there are any — (Laughter) (Applause) I've got a red dot on my forehead now, don't I? (Laughter)
Kjo me con mua ne nje pyejte te dukshme dhe ne nje pyetje shqetesuese: A ka parazite te keqinj, shpirtezi qe po ndikojne ne sjelljen tone pa e ditur ne, pervec NSA? Nese ka ndonje - (Te qeshura) (Duartrokitje) Kam nje pike te kuqe ne balle tani, apo jo? (Te qeshura)
If there are any, this is a good candidate for them. This is Toxoplasma gondii, or Toxo, for short, because the terrifying creature always deserves a cute nickname. Toxo infects mammals, a wide variety of mammals, but it can only sexually reproduce in a cat. And scientists like Joanne Webster have shown that if Toxo gets into a rat or a mouse, it turns the rodent into a cat-seeking missile. If the infected rat smells the delightful odor of cat piss, it runs towards the source of the smell rather than the more sensible direction of away. The cat eats the rat. Toxo gets to have sex. It's a classic tale of Eat, Prey, Love. (Laughter) (Applause)
Nese ka ndonje, ja ku eshte nje kandidat i mundshem per ta. Kjo eshte Toxoplasma gondii ose shkurt, Tokso, per shkak te natyres tmerruese gjithmone ka nevoje per nje nofke te lezetshme. Tokso infekton gjitaret, nje shumellojshmeri gjitaresh, por mund te riprodhohet seksualisht vetem tek macet, Shkencetaret si Joanne Webster kane treguar qe nese Tokso futet tek nje mi, ajo e kthen brejtesin ne nje rakete ne kerkim te maces. Nese miu i infektuar ndjen eren e kendshme te urines se maces ai vrapon drejt burimit te eres jo ne drejtimin e kundert sic duhet e beje. Macja e ha miun. Tokso mund te beje seks. Eshte nje histori klasike e Ha, Gjuaj, Dashuro (Te qeshura) (Duartrokitje)
You're very charitable, generous people. Hi, Elizabeth, I loved your talk.
Ju jeni shume bamires, njerez bujare. Pershendetje Elizabete. Me pelqeu fjalimi yt.
How does the parasite control its host in this way? We don't really know. We know that Toxo releases an enzyme that makes dopamine, a substance involved in reward and motivation. We know it targets certain parts of a rodent's brain, including those involved in sexual arousal. But how those puzzle pieces fit together is not immediately clear. What is clear is that this thing is a single cell. This has no nervous system. It has no consciousness. It doesn't even have a body. But it's manipulating a mammal? We are mammals. We are more intelligent than a mere rat, to be sure, but our brains have the same basic structure, the same types of cells, the same chemicals running through them, and the same parasites. Estimates vary a lot, but some figures suggest that one in three people around the world have Toxo in their brains. Now typically, this doesn't lead to any overt illness. The parasite holds up in a dormant state for a long period of time. But there's some evidence that those people who are carriers score slightly differently on personality questionnaires than other people, that they have a slightly higher risk of car accidents, and there's some evidence that people with schizophrenia are more likely to be infected. Now, I think this evidence is still inconclusive, and even among Toxo researchers, opinion is divided as to whether the parasite is truly influencing our behavior. But given the widespread nature of such manipulations, it would be completely implausible for humans to be the only species that weren't similarly affected.
Si e kontrollon paraziti mbartesin e tij ne kete menyre? Nuk e dime ne te vertete. Ne dime qe Tokso leshon nje enzime qe prodhon dopaminen, nje substance e cila perfshihet ne shperblim dhe motivim. Ne e dime se targeton pjese te vecanta te trurit te brejtesit duke perfshire ato qe perfshihen ne zgjimin seksual. por sesi keto pjese te gjezes bashkohen sebashku nuk eshte akoma e qarte. Ajo qe eshte e qarte eshte se kjo gje eshte nje qelize e vetme. Nuk ka sistem nervor. Nuk ka ndergjegje. Nuk ka bile as trup. Por po manipulon nje gjitar? Ne jemi gjitare. Ne jemi me inteligjente sesa nje mi, me siguri, por truri jone ka strukturen bazike, te njejtat qeliza te trurit, te njejtet lende kimike qe rrjedhin ne te, dhe te njejtin parazite. Vleresimet variojne shume, por disa shifra tregojne se nje ne tre njerez ne bote kane Tokso ne trurin e tyre ne pergjithesi, kjo nuk con ne asnje semundje. paraziti qendron ne gjendje te fjetur per nje periudhe te gjate kohe. Por ka disa evidenca se keta njerez qe jane mbartes kane rezultate te ndryshme ne pyetesoret e personalitetit nga personat e tjere, qe kane nje risk me te larte per aksidente me makine, dhe ka evidence se njerezit me skizofreni ka shume te ngjare te jene te infektuar. Tani, une mendoj se kjo evidence eshte akoma te paperfunduar, edhe bile ndermjet kerkuesve te Toxo, opinionet jane te ndryshme nese paraziti ndikon vertet ne sjelljen tone. Por duke pare perhapjen kaq te madhe ne natyre te manipulimeve te tilla, do te ishte plotesisht e pabesueshme qe njerezit te jene qeniet e vetme qe te mos preken ne menyre te njejte.
And I think that this capacity to constantly subvert our way of thinking about the world makes parasites amazing. They're constantly inviting us to look at the natural world sideways, and to ask if the behaviors we're seeing, whether they're simple and obvious or baffling and puzzling, are not the results of individuals acting through their own accord but because they are being bent to the control of something else. And while that idea may be disquieting, and while parasites' habits may be very grisly, I think that ability to surprise us makes them as wonderful and as charismatic as any panda or butterfly or dolphin.
Une mendoj se ky kapacitet qe ne menyre konstante saboton menyren sesi ne mendojme per boten i ben parazitet te habitshem. Ata ne menyre te vazhdueshme na ftojne te shohim me dyshim boten natyrore dhe te pyesim nese sjelljet qe po verejme qofshin ato te thjeshta dhe te dukshme, ose te pakuptueshme dhe enigmatike, nuk jane rezultat i individeve te cilet veprojne sipas arsyes se tyre por sepse ato kane rene nen kontrollin e dickaje tjeter. Nderkohe qe kjo ide mund te jete shqetesuese dhe nderkohe qe sjelljet e paraziteve mund te jene shume te frikshme une mendoj se aftesia per te na habitur ne i ben ata me te mrekullueshem dhe me karizmatike se cdo pande apo flutur apo delfin.
At the end of "On the Origin of Species," Charles Darwin writes about the grandeur of life, and of endless forms most beautiful and most wonderful, and I like to think he could easily have been talking about a tapeworm that makes shrimp sociable or a wasp that takes cockroaches for walks.
Ne fund te " Mbi origjinen e specieve" Carls Darvini shkruan mbi madheshtine e jetes dhe mbi format e pafundme me te bukura dhe me te mrekullueshme dhe mua me pelqen te mendoj se ai mund te kete qene duke folur per shiritin qe i ben karkalecat e shoqerueshem ose nje grerez qe e nxjerr buburrecin shetitje.
But perhaps, that's just a parasite talking.
Por ndoshta, kjo eshte thjesht nje e folur paraziti.
Thank you.
Ju falemnderit.
(Applause)
(Duartrokitje)