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Did Insects Kill the Dinosaurs?

Posted by Zonk on Fri Jan 04, 2008 01:25 PM
from the big-and-little dept.
Ponca City, We Love You writes "Asteroid impacts, massive volcanic flows, and now biting, disease-carrying insects have been put forward as an important contributor to the demise of the dinosaurs. In the Late Cretaceous the world was covered with warm-temperate to tropical areas that swarmed with blood-sucking insects. A theory explored by researchers at Oregon State suggests these bugs carried leishmania, malaria, intestinal parasites, arboviruses and other pathogens. Repeated epidemics may have slowly-but-surely worn down dinosaur populations while ticks, mites, lice and biting flies tormented and weakened them. 'After many millions of years of evolution, mammals, birds and reptiles have evolved some resistance to these diseases,' says Researcher George Poinar. 'But back in the Cretaceous, these diseases were new and invasive, and vertebrates had little or no natural or acquired immunity to them.' The confluence of new insect-spread diseases, loss of traditional food sources, and competition for plants by insect pests could all have provided a lingering, debilitating condition that dinosaurs were ultimately unable to overcome."
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  • Mosquitos (Score:5, Funny)

    by somersault (912633) on Friday January 04 2008, @01:26PM (#21911958) Homepage Journal
    Dinosaurs couldn't slap mosquitos, so they all caught malaria?
    • No... the Dinosaurs were just fine at slapping mosquitoes, it's just that jerk Adam liked to play practical jokes and would put mosquitoes on their beds at night.
    • Seems odd (Score:4, Insightful)

      by Anonymous Coward on Friday January 04 2008, @02:14PM (#21912684)
      'But back in the Cretaceous, these diseases were new

      They were new? I am by no means an authority on the subject, but from what I remember learning about evolution, one-celled-organisms came along before cell colonies. Further, small cell colonies (bugs and such) came around before big ones (dinosaurs and such). I even recall learning that the first self-replicating DNA strands were much more virus-like than bacteria-like...since the whole membrane and organelle system didn't come about until a bit later.

      So, by the time the dinosaurs were around, the world should have already been densely populated with viruses, bacteria, and small bugs which could find the guts of a dinosaur to be fertile breeding grounds.

      I really don't see how these things, and the diseases they cause, could have come around after the fact. Maybe some more sinister versions of them, more specifically targeted at the dinosaurs of the day, came around after the fact, but I don't think that alone would account for a mass extinction.

      If you have corrections to offer, don't hold back (not that you would).

      • Vectors! Insect became disease carrying vectors about the time of the cretaceous.

        They were not claiming that these diseases did not exist until this time. They are saying that the diseases adapted to insects and used the insects as carrying agents at far back as the cretaceous period, maybe longer.

          • Re: (Score:3, Interesting)

            Not so much "funny" as "insightful."

            In fact, since insects had been *The* animal ecosystem on land for millions of years before the first vertebrates skulked out of the ocean, it's pretty plausible that all manner of mites and parasites had existed and passed around proto-diseases--lets not forget that even today, our insects are covered with even tinier insect parasites. Parasites of all sorts also existed in the oceans where the vertebrates were evolving. Parallel evolution makes much, much more sense.
            • Insects (Score:3, Interesting)

              I think the claim is that instigating event was the evolution of flowering plants. That triggered an explosion in the biodiversity of plants, insects, and small fast-evolving animals like wee lizards and mammals. Animal biodiversity leads invariably to pathogen diversity, as there are more combinations of organisms between which pathogens can transfer and which can participate in parasite life-cycles.

              The vast majority of flowers are intended to attract insects. Think about the most notorious disease-sp

  • This seems unlikely to me. As far as I can tell, every single type of dinosaur died out except for those that went on to become birds. This is like future, intelligent insects blaming the plague for the demise of every type of mammal on the planet.
    • Re: (Score:3, Insightful)

      The sharks, ceolocanths, and 'gaters may beg to differ with ya...
      • Re:extremely suspect (Score:5, Informative)

        by JerryLove (1158461) on Friday January 04 2008, @02:09PM (#21912602)
        Although "Dinosaur" is used very widely, and often used to refer to extinct reptiles like the Pliseosaur, Pteridon, or Leoplurodon; the groups wiped out were, properly speaking, the Therapods (popularly the T-Rex, Velociraptors, and their kin) and the Sauropods (Brachiasaur, Triceritops, etc). Neither of these groups survived the mass extinction at the end of the Cretatious period.

        Sharks are sharks, Ceolocanths are fish, and Aligators are reptiles. Although all three forms date back very nearly how they look now to the time of the dinosaurs, it would be an equivocation to call them "dinosaurs" when discussing the "extinction of the dinoasurs".

        Apologies for spelling, mine is pretty poor.
        • Re:extremely suspect (Score:5, Informative)

          by Weedlekin (836313) on Friday January 04 2008, @03:15PM (#21913620)
          "and the Sauropods (Brachiasaur, Triceritops, etc)"

          Triceratops wasn't a sauropod. Like other marginocephalians, it was a member of one of three orithischian (bird hipped) groups (the other two are threophora which includes armoured dinosaurs such as ankylosaurus and stegosaurus, and ornithopods such as the hadrosaurs). Sauropods were saurischian (lizard hipped), and are therefore more closely related to therapods than either are to the ornithischians.
    • by Serenissima (1210562) on Friday January 04 2008, @01:46PM (#21912284)
      It might work! But only if that insects - along with carrying various diseases - also carried giant, planet-killing asteroids with them. If we just call the "Dinosaur Period" the Jurassic through Cretaceous, that lasted from 200 million years before now to 65 million years before now (+/- 5-10 million years). I find it kind of hard to swallow that Dinosaurs couldn't build up an immunity to disease over a period of 135 [i]million[/i] years. Viruses can evolve and change hundreds of times in the course of a human lifetime (which you can't even measure with Geologic time). If Viruses were around for 135 million years when Dinosaurs were around, the Dinosaurs had to have pretty hefty immune systems to be able to cope with all the new viruses evolving. And considering that they actually lasted until a giant rock fell out of the sky, I'd say that getting head colds probably didn't do them in.
    • You are absolutely correct. The authors must have made that same old error. It is done again and again. Over and over.

      Why can't people understand, birds are the dinosaurs that survived.

      Birds relate to dinosaurs as bats relate to mammals. Or, birds relate to dinosaurs as butterflies relate to insects. It is as simple as that.

      That, unread, article must be bad.

        • Re: (Score:3, Informative)

          "In other terms, birds are descendants and cousins of dinosaurs, but they are not a species of dinosaur."

          Sorry, but that was an example of the common misconception I was trying to point out. Contrary to your proposal, birds _are_ a group of species of dinosaurs.

          If all mammals, except the bats for example, went extinct, your favorite bat would not seize or stop being a mammal. And the number of very specific adaptations of the bats would NOT set them apart (sonar, leathery wings, wrinkled noses, large ears,
    • A disease which kills it's host off too quickly will itself die out in short order before becoming too widespread.
      • Aids (originally from Chimps?) takes years to kill, allowing the host to infect others.
      • Bubonic Plague was a disease for rats. It killed a lot but not to the extent of exterminating entire species. Humans have developed resistance.
      • Ebola? Endemic in some monkey species, outbreaks amongst humans cause so much damage that the disease fails.
      • Malaria: kills a lot, but humans have developed resistan
    • Between meteor strikes, volcanoes, ice ages, and mosquitoes, they didn't have a chance.
      and all within the past 6000 years...
      the first lawyer was probably the deathknell.
      • Re:extremely suspect (Score:5, Interesting)

        by flyingsquid (813711) on Friday January 04 2008, @03:43PM (#21914196)
        The end-Cretaceous mass extinction did not just target the dinosaurs. It resulted in the extinction of dinosaurs, pterosaurs, the vast majority of birds, many mammals and lizards, a few turtles and crocodilians, frewshwater sharks, freshwater clams, large marine reptiles (mosasaurs and plesiosaurs), ammonites (shelled cephalopods similar to the modern chambered nautilus), marine plankton, many species of plants... and ironically enough, some insects. The insect fossil record isn't good enough to look at extinction patterns, but if you look at fossil leaves, a number of distinctive feeding traces disappear 65 million years ago, at the same time as the dinosaurs, indicating that whatever plant-eating insects made them went extinct.

        In short, it is unlikely that biting insects could be responsible for all this chaos. The extinction was simultaneous, worldwide, and (in geological terms) instantaneous, it hit animals and plants, and it hit organisms on land and in the sea. Now, it turns out, probably not coincidentally, that at the same time all of this happens, a huge asteroid or comet impact- one of the biggest in the past half-billion years- takes place in the Yucatan, blasting dust into the stratosphere, sending tidal waves across Texas, and probably igniting much of North America in the process. An asteroid impact is probably capable of causing an extinction like this. Its doubtful that gnats, mites, and mosquitos could.

  • by orclevegam (940336) on Friday January 04 2008, @01:29PM (#21912010) Journal
    Ok, lets just make them all happy and say all of the above played a part. Giant meteor hits the Earth, causes dust to obscure the sun and weakens or kills a bunch of plant life. Meanwhile that same impact touches off a bunch of giant lava flows. Finally the dinosaurs already weakened by lack of food are subject to malaria and cough to death on dust clouds. There, all major doom scenarios all rolled into one. Please note, I'm not really serious with this... or am I?
  • by Blakey Rat (99501) on Friday January 04 2008, @01:30PM (#21912014)
    I learned it on MST3K during the movie Future War (which isn't set in the future and doesn't feature a war, natch.)

    http://en.wikiquote.org/wiki/Mystery_Science_Theater_3000#Future_War [wikiquote.org]

    Thank you for not killing me.
  • MalaRIAA (Score:5, Funny)

    by owlnation (858981) on Friday January 04 2008, @01:30PM (#21912016)
    Dinosaurs? Bloodsucking Insects?

    Is this another Music Industry article?
  • 'But back in the Cretaceous, these diseases were new and invasive, and vertebrates had little or no natural or acquired immunity to them.'
    Back in the Cretaceous, these diseases were 70 million years' evolution behind where they are now. It's really quite a leap to presume they were so virulent that inborn immunity was necessary.
      • Too virulent is bad for the host and parasite, so that is an argument against the parasites flourishing in that setting.

        What nixes this idea for me is that the microbes didn't grow on Mars and suddenly rain on the dinosaurs out of the blue. Microbes and reptiles all had to grow up together.
  • Bernard Werber (Score:4, Interesting)

    by Scrameustache (459504) on Friday January 04 2008, @01:35PM (#21912092) Homepage Journal
    A French sci-fi author suggested that ants deliberately waged war on dinosaurs and killed them all (by invading their natural orifices and killing them from the inside) because their large size was detrimental to ant nests.

    But frankly, I don't think new diseases would wipe out an entire order of life, all over the world, in all ecological niches, without wiping out other unrelated orders of life. In their hundreds of millions of years of existence, dinos had to fight off insects and diseases that were there before them, it couldn't just wipe them (and just them) off the face of the Earth in such a short time.
  • 'After many millions of years of evolution, mammals, birds and reptiles have evolved some resistance to these diseases,' says Researcher George Poinar. 'But back in the Cretaceous, these diseases were new and invasive, and vertebrates had little or no natural or acquired immunity to them.'

    Uh, exactly why would mammals have some natural resistance to these diseases such that they would survive better than the dinosaurs? Especially considering that some mammals (e.g., humans) don't have resistance to Mala

    • Re:Hold the phone (Score:4, Interesting)

      by Henry V .009 (518000) on Friday January 04 2008, @01:59PM (#21912442) Journal
      It's not specific blood-bourne pathogens, it's blood-bourne pathogens in general. We have lots of complicated mechanisms that have developed over millions of years of evolution that provide a lot of protection.

      And yes, there are a number of genes that code for malaria resistance in human beings; they exist wherever malaria is common. The most well known (and most common?) is the sickle cell gene. But there are a number of other mechanisms that have evolved independently that protect people from malaria. If your ancestors had a lot of trouble with malaria, you are probably much more resistant to it than someone whose ancestors came from Norway.
  • parasites don't suddenly appear out of thin air and reduce their hosts to extinction

    they gradually evolve in tandem with their hosts, and they make sure they always leach off the host's resources, and never kill their host

    a parasite is not interested in killing its host. because then the parasite dies too

    and a parasite is evolved to infect its host very carefully and specifically. dinosaurs did not suddenly get worms that no other creature ever got before. the worms evolved as the dinosaurs evolved

    as for biting insects, this was a major new change. but again, it's not like mosquitoes materialized out of thin air and vampirically drained all the blood in the world. they slowly and gradually evolved to the job they do better and better, but never THAT good a job. never, never, did they kill their hosts. because this would then kill the mosquitoes

    so frankly, this story is braindead on some fundamentals of evolution and parasites
    • by Sciros (986030) on Friday January 04 2008, @01:49PM (#21912332) Journal
      You're mistaken on the principle of parasitism, possibly confusing it on some level with symbiosis. Parasites don't need to keep a host alive. Many parasites kill their hosts (as intended). Parasitic wasps, for instance, lay eggs inside their hosts which then hatch with the larva proceeding to eat the host from the inside out. Such wasps are in fact sometimes used as a "natural" method of pest control.
      • that parasitic wasps are going to wipe out their hosts?

        of course not

        therefore, you understand my point of the supidity of saying parasites wiped out the dinosaurs
        • Re: (Score:3, Insightful)

          There is no intelligence involved in the parasite - they cannot make the decision not to wipe out the host species.
          A Parasite that develops and is virulent enough to wipe out its host species will go extinct as a result of doing so. An evolutionary dead end, certainly, but undoubtedly an evolutionary dead-end that has occurred more than once in earthly history. Nothing and no one will step in to prevent this from happening (well, at least in my theology).
          In that sense, a "successful" parasite is relat
        • Re: (Score:3, Insightful)

          parasitic wasps are going to wipe out their hosts?

          Well no, current species of parasitic wasps aren't generally going to; however that's just because the ones that survived up until now are the ones that stumbled upon a method that leaves a host population in tact. This doesn't mean that previous parasites didn't get overzealous and bring about their own extinction by killing all their hosts.

          There's nothing about evolution which inherently prevents a species from ending itself...you just don't encounte

  • The theory seems a little bit of a stretch, but the recent work suggests that the KT meteor event may have been the straw that broke an ailing camel's back.

    Still, lots of stuff did survive, and because "dinosaur" is a rather large and diverse group of animals, the best we can say is that it was, by and large, the megafauna that took the brunt of it, which seems logical, as it would be these species that would be at the top of their prospective ecological niches, and thus the most vulnerable.
  • id (Score:4, Funny)

    by wwmedia (950346) on Friday January 04 2008, @01:39PM (#21912188)
    this theory would fit nicely with the "world is only 6000 years old crowd"

    i mean swarms of insects were mentioned in the bible (old testament, moses exodus part?) somewhere, i dont remember reading about asteroids in that book
    • in the bible (old testament, moses exodus part?) somewhere, i dont remember reading about asteroids in that book
      Then the LORD rained down burning sulfur on Sodom and Gomorrah--from the LORD out of the heavens.
  • arboviruses
    So wait, wait, wait. Wait. You're saying that TREES killed the dinosaurs, using the insects as their hit men?
  • by Sciros (986030) on Friday January 04 2008, @01:41PM (#21912206) Journal
    The whole timeline appears a bit fubar here.

    "After many millions of years of evolution, mammals, birds and reptiles have evolved some resistance to these diseases,' says Researcher George Poinar. 'But back in the Cretaceous, these diseases were new and invasive, and vertebrates had little or no natural or acquired immunity to them"

    Um, the Cretaceous period lasted 75 million years. So while it's plausible that insects caused outbreaks of disease in localized populations I really don't see how anything of pandemic proportions can be inferred. As far as evolved resistance goes, well, the dinosaurs dominated the Earth for a LONG time. Much, much longer than mammals. Unless the diseases described all appeared about 65 million years ago, then there's just no logic here.

    Besides that, dinosarus may have died out but many other species did not. This includes reptiles, which would have been affected by the pathogens according by these researchers.

    The more I think about this, the more it smells like bullcrap.
    • Re: (Score:3, Interesting)

      It's even more unlikely than that: pathogens have absolutely been part of the ecosystem since the days of single-celled life forms. There are organelles in a modern animal or plant cell, including mitochondria and chloroplasts, that are believed to have evolved from symbiotic organisms. These almost certainly started out as pathogens back when the whole multicellular complex organism schtick was just starting up.
  • by zappepcs (820751) on Friday January 04 2008, @01:41PM (#21912220) Journal

    "We can't say for certain that insects are the smoking gun, but we believe they were an extremely significant force in the decline of the dinosaurs," Poinar said. "Our research with amber shows that there were evolving, disease-carrying vectors in the Cretaceous, and that at least some of the pathogens they carried infected reptiles. This clearly fills in some gaps regarding dinosaur extinctions."
    I think that in view of the asteroid disaster and limited sustenance material in its aftermath the diseased insects could do damage to already suffering species. In the short term this would be no major issue, but descriptions of the asteroid's damage show that it would have been decades of knock-on effects to climate and biology. If smaller (low on the food chain) animals suffered first, it would lead to shortages and starvation up the chain. Is that enough to cause mass extinction? Who knows, but it seems plausible enough to be worth counting in the list of causes.

    You might ask what happened Mayan empire? http://en.wikipedia.org/wiki/Maya_collapse [wikipedia.org] This insect thing might not be so far fetched as you think?
  • Which came first? (Score:3, Insightful)

    by DarkTitan_X (905442) on Friday January 04 2008, @01:44PM (#21912248) Homepage
    Did insect-borne illnesses weaken the dinosaur species that went extinct before the meteor impact that ultimately led to their extinction, or did the geologic changes caused by the meteor impact weaken the dinosaurs to make them more susceptible to illness?
  • Admittedly I didn't RTFA, but are these scientists saying that the dinosaurs WEREN'T killed by the huge Chixulub asteroid? I thought it had been pretty much established that that was what happened (iridium concentrations at the K-T boundary, 65M-year old impact crater, 70% of other species kicking the bucket at the same time, etc.)
  • It seems very unlikely that a whole planet of dinosaurs were killed by insects. It is actually very difficult for insects to cover an entire continent, let alone move from continent to continent. In current times, insects stowaway on ships and planes to travel large distances and between continents. Also, if this were true regarding reptiles, what about crocodiles? They've been living much longer than any of the dinosaurs and the lived in conditions where mosquitoes thrive. How do you explain them?
  • OMG ZERG RUSH! :)
  • by simon_k_lee (1212648) on Friday January 04 2008, @02:01PM (#21912488)
    Com'on. Somebody needs a graduate degree and/or funding gotta come up with some sort of original research, regardless of how far fetched it is. Welcome to the dark side of academia.
  • by 140Mandak262Jamuna (970587) on Friday January 04 2008, @02:04PM (#21912534) Journal
    There could be something to this theory. Flowering plants originates at about the same time dinosaurs conked out. And to aid pollination by insects, the plants started making high octane fuels (nectar, is almost pure sugar) and the co-evolution of insects and flowering plants raced ahead. There could be something to it, but still we would need more positive evidence. We still have to explain the iridium layer in sediments too.
  • True believers know it was a giant floating brain [wikipedia.org], while the heretics believe it was from a virus-laden powerplant worker [wikipedia.org].
  • This hypothesis needs to explain who the little feather dinosaurs survived and the others didnt.