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Wednesday, June 01, 2005

Questing Behavior

We have lots of ticks around here so naturally Melina asked Jeeves: "how does a tick get on me?" because our argument about whether ticks fall out of trees or creep up our pants legs is getting us nowhere.

Jeeves sent us to a page about the Biology of Ticks by Larisa Vredevoe, Ph.D. who tells us:

Approximately 850 species have been described worldwide.

There are two families of ticks, hard ticks and soft ticks. Our ticks are hard ticks, which have three life stages:
  1. Larvae, which have six legs when they emerge from the egg. They enjoy a blood meal from a host (me for example) and then molt to the nymphal stage - and acquire eight legs!

  2. Nymphs feed and molt to the next and final stage - the adult.

  3. The adult female feeds once more and lays one batch of several thousand eggs and then dies.

OK, this is the best part:

"Hard ticks seek hosts by an interesting behavior called "questing." Questing ticks crawl up the stems of grass or perch on the edges of leaves on the ground in a typical posture with the front legs extended, especially in response to a host passing by.

Certain biochemicals such as carbon dioxide as well as heat and movement serve as stimuli for questing behavior.

Subsequently, these ticks climb on to a potential host which brushes against their extended front legs.

Having read this, we are adding questing behavior to our own daily routines. At moments when something is wanted or required, simply stand with arms straight, extended upwards and forwards, in a yearning and hopeful attitude. "Wave the forelegs to and fro slowly." (more.)

It can take three years for ticks to go through the cycle if no host is found. They are patient and can go several months without feeding.

You can see the outer parts of the tick's mouth move back and forth, huge pincers which protect the prickly inside parts (which face their barbs backwards to thwart our removing them). Then there's the plunger, of course.

In addition to the barbs, ticks have cement-like spit which glues them in place until feeding is complete and they want to drop off and do the next thing on their list.

The outside hard surface of the tick grows to accommodate the ingested blood, anywhere from 200-600 times the tick's body weight.

Lastly: Ticks usually do not climb very high and there is no evidence to suggest that they fall out of trees.

UPDATE: so as we were thinking some more about "questing" we realized that once a tick is up on the end of that leaf of grass waving its arms about, hopefully, there is no reason for it ever to come down, right, because it has no extra-curricular activities and it can't do its next thing until it has a meal, so why would our lawn not be full of ticks just standing on their tiptoes on blades of grass, waiting, all day and all night, just standing, just waiting, little hungry ticks, hoping we will come by... see Melina's comment below.

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At 6:32 AM, Anonymous Anonymous said...

I have a house for sale that isn't moving. Maybe I should stand on the roof "questing"... LOL

At 7:14 AM, Blogger Badaunt said...

I've noticed before that when you look at insects close up, you start feeling like you're in a science fiction movie.

Ticks are a bit different though, aren't they. They seem to belong to the Middle Ages. They're looking for the Holy Grail. (Of blood, presumably... or is that leeches?)

At 7:29 AM, Blogger Hannah said...

I thought it would reassure me to learn they don't fall out of trees, but this seems even worse somehow.

At 9:08 AM, Anonymous Anonymous said...

It "almost" makes you feel for the tick's point of view, until you get to the part about the plunger and the spit glue! This is the sort of information that will stick in my mind for a long time.

At 10:17 AM, Anonymous Anonymous said...

great info on the little deer's friends.

The "more" link gets a 404 now.

At 10:30 AM, Blogger melinama said...

Thanks Pearl - I fixed the link! Glad to know you wanted to know more about ticks!

At 9:20 PM, Blogger Erin said...

Great, I used to feel tick-safe by staying away from the trees, now I'm afraid to walk through the lawn!

I wonder how I'll tell the husband that I'm not mowing anymore!?

At 11:36 PM, Blogger Ron Hudson said...

I swear I have seen human babies questing and then expanding to 200-600 times their body weight when they find milk!


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