Thursday, 3 December 2009

Ticks on Blue-tongue Lizard

(Edited on 21st Dec 2009 to reflect new information)

This Blotched blue-tongue Lizard (Tiliqua nigrolutea) was found here in my backyard. Closer inspection showed it to be covered in ticks, mostly at the back of the neck as well as in the axilla or armpit.

One fully gorged tick was actually causing the lizard discomfort (judging by the way it was walking) so we decided to remove them. Blue-tongue lizards are quite commonly parasitised by ticks. In fact some species of tick only feed on reptiles. Of the nine ticks we removed there were three distinct types. I had originally thought that these were three separate species but thanks to the helpful advice from Dr Bruce Halliday and Prof. Michael Bull I now know that they are all the same. They are the Southern Reptile Tick, Bothriocroton hydrosauri formerly known as Aponomma hydrosauri. There were more ticks in the lizards ears but I did not want to risk causing damage as their ear drums are close to the surface. A local herpetologist recommended putting vegetable oil on the ticks which should cut off their air supply and get them to drop off. This might be worth a try if your squeamish but it did not work for me. I've since been told:

"It is quite ok to physically pull the ticks from the ear. There may be a little bleeding but it is temporary, and probably far more effective than any oil treatment. Actually the ticks do little damage to the lizard unless there is an excessive load, and indeed they are just as much a component of the biodiversity as the lizards, so it is probably best just to leave the natural interaction intact. The fully engorged female tick you found in the axilla of the arm, may have caused a little discomfort, but they only remain in that state for a very short period of time before detaching to lay eggs."

The following taxonomy is based on the "Australian Faunal Directory" web site.

  • Phylum: Arthropoda
  • Class: Arachnida
  • Superorder: Acarina
  • Order: Parasitiformes
  • Suborder: Mesostigmata
  • Superfamily: Ixodoidea

    • Family Argasidae (Soft ticks)
    • Family Ixodidae (Hard Ticks)

You can clearly see the scutellum (shield like plate at the back of the head) in two of my ticks photos below which is a feature of Hard Ticks ( Ixodidae). I had thought Tick C below was of the Argasidae as there seemed to be no obvious scutellum. This turned out to be a case of not seeing the forest from the trees as apparently in the male the scutellum covers the whole body.


(Click on photos to enlarge)
Blotched blue-tongue Lizard (Tiliqua nigrolutea)


A fully gorged tick in the the axilla as well a a smaller one of a different species below it.


Ticks (Bothriocroton hydrosauri )under the scales on the back of the lizards neck.


Tick A - An engorged female (Bothriocroton hydrosauri )

Tick B - A female in the unengorged state (Bothriocroton hydrosauri )


Tick C - A male (Bothriocroton hydrosauri )
these do not become engorged like the females do




10 comments:

  1. Yikes! No wonder the blue-tongue wasn't moving freely.

    There's been quite a bit of work done on ticks of shinglebacks in South Australia. Not sure how applicable that would be to blue tongues or Tassie, though. (You can see that I'm striving for the least informative comment award!)

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  2. Considering the damage even one small tick does to me - I am VERY sorry for that Bluetongue! I hope your tick removal made it more comfortable!

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  3. Thanks Snail - Sounds interesting. I've just ordered one called "The Tick Fauna of Tasmania". At the very least it may cure my insomnia :-)

    Thanks Mick - Yes I don't generally like interfering with things but IMHO sometimes you have to.

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  4. Blue-tongue must be tickled pink at ticklessness.

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  5. Hi Mosure.
    Your Ixodes Sp. looks very similar to a Paralysis Tick which was recently removed from a dog here.
    Surprised to find them as far south as your area.
    Maybe not as dangerous - who knows, but certainly very similar in size and design.
    They are commonly found on Echidnas and Wallabies here.
    I have never seen them on Lizards before.
    Great images, by the way. Fascinating to see them jammed in between the scales.
    Discomfort certainly, but local vets and Wires people say that native animals have developed immunity to their toxins.
    Makes sense.
    Cheers
    Denis

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  6. ...I don't feel well. Haha! Well done on helping the Blue Tongue. I had no idea this could be a problem for reptiles -- there you go. You learn something new every day!

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  7. Sorry for the late replies. I've been away...

    Thanks Tony - I'll bet it didn't tickle when I removed them.

    Thanks Denis - It does look very similar to the one on your blog. We do get the Paralysis Tick in Tassie but allegedly only on the east coast. I hope I don't have them in the backyard.

    Thanks Sebastian - yes there's always something new to see. That why the natural world fascinates me.

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  8. This post was edited on 21st December 2009) to reflect new information I have received on the above ticks.

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  9. Well, there you go.
    We feel obliged to intervene un-necessarily, it seems.
    "indeed they are just as much a component of the biodiversity as the lizards, so it is probably best just to leave the natural interaction intact."
    A "tough call" but makes sense.
    .
    Good to know more about the local species of Ticks.
    .
    Cheers
    Denis

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  10. Oh my gosh! Your photos are great but those ticks give me the creeps, especially that huge whistish balloony one.

    I'd love to see more blue tongues more often, have only ever seen them in the wild once around Waterworks Reserve.

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