Deathly drool: evolutionary and ecological basis of septic bacteria in Komodo dragon mouths.
Bull JJ, Jessop TS, Whiteley M.
Abstract
Komodo dragons, the world's largest lizard, dispatch their large ungulate prey by biting and tearing flesh. If a prey escapes, oral bacteria inoculated into the wound reputedly induce a sepsis that augments later prey capture by the same or other lizards. However, the ecological and evolutionary basis of sepsis in Komodo prey acquisition is controversial. Two models have been proposed. The "bacteria as venom" model postulates that the oral flora directly benefits the lizard in prey capture irrespective of any benefit to the bacteria. The "passive acquisition" model is that the oral flora of lizards reflects the bacteria found in carrion and sick prey, with no relevance to the ability to induce sepsis in subsequent prey. A third model is proposed and analyzed here, the "lizard-lizard epidemic" model. In this model, bacteria are spread indirectly from one lizard mouth to another. Prey escaping an initial attack act as vectors in infecting new lizards. This model requires specific life history characteristics and ways to refute the model based on these characteristics are proposed and tested. Dragon life histories (some details of which are reported here) prove remarkably consistent with the model, especially that multiple, unrelated lizards feed communally on large carcasses and that escaping, wounded prey are ultimately fed on by other lizards. The identities and evolutionary histories of bacteria in the oral flora may yield the most useful additional insights for further testing the epidemic model and can now be obtained with new technologies.
PLoS One. 2010 Jun 21;5(6):e11097.
Abstract
Komodo dragons, the world's largest lizard, dispatch their large ungulate prey by biting and tearing flesh. If a prey escapes, oral bacteria inoculated into the wound reputedly induce a sepsis that augments later prey capture by the same or other lizards. However, the ecological and evolutionary basis of sepsis in Komodo prey acquisition is controversial. Two models have been proposed. The "bacteria as venom" model postulates that the oral flora directly benefits the lizard in prey capture irrespective of any benefit to the bacteria. The "passive acquisition" model is that the oral flora of lizards reflects the bacteria found in carrion and sick prey, with no relevance to the ability to induce sepsis in subsequent prey. A third model is proposed and analyzed here, the "lizard-lizard epidemic" model. In this model, bacteria are spread indirectly from one lizard mouth to another. Prey escaping an initial attack act as vectors in infecting new lizards. This model requires specific life history characteristics and ways to refute the model based on these characteristics are proposed and tested. Dragon life histories (some details of which are reported here) prove remarkably consistent with the model, especially that multiple, unrelated lizards feed communally on large carcasses and that escaping, wounded prey are ultimately fed on by other lizards. The identities and evolutionary histories of bacteria in the oral flora may yield the most useful additional insights for further testing the epidemic model and can now be obtained with new technologies.
PLoS One. 2010 Jun 21;5(6):e11097.
Why is this cool?
Does any child fascinated with knights in armor ever lose their awe when just the word "DRAGON" comes up? The answer is no. A resounding no. Komodo DRAGONS rock just from their name and when one digs deeper, they keep rocking. Like Nicolas Cage air-guitaring, it keeps getting better. Komodos are gigantic, poisonous, and fierce looking. All the elements deserving of reverence by many a male youth.
Did you know that when the GREAT BEAST KNOWN AS DRAGON bites not only does it have venom, but it also doses the prey with some septic bacteria? I didn't know, but I don't know very much so that is no surprise. What does septic mean? It means that the bacteria can quickly flood the hosts immune system leading to death. Today's paper asks the question: where did this septic bacteria come from? Currently, there are three models of bacterial transmission:
1. Normal bacteria in DRAGON mouth evolved to be useful as a poison.
2. When animals die and the DRAGONS eat the meat, the bacteria associated with rotting meat get into DRAGON mouths and this is transferred to later prey.
3. Somehow a septic bacteria got into one DRAGON'S mouth and through communal eating that bacteria was spread to others.
DNA sequencing and comparing those DNA sequences can tell one the evolutionary history of bacteria and that is what the researchers did. They found that the data supports the third option.
As far as menacing creatures go, komodo DRAGONS are pretty lame. They are not found anywhere that Europeans will fight them. They are actually too far from Japan to help young girls recover their parents! Plus, they don't breath fire or fly! The best DRAGON ever was probably FALKOR!!!
Although, the most badass, eat your family in front of you DRAGON would have to be KING GHIRODAH!!!
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