Saturday, November 12, 2011


I hate leeches!
Not because of what they are but what they do me. A leech bite leaves a nasty red lump on me that can itch for months.
Recently the co driver found a big leech (see pic) lying in a pool of blood on the carpet. A quick inspection found that it had dropped off my leg after a day out spraying the vines. Despite wearing knee length rubber boots it had found its way in. Serves me right for not spraying my pants legs and boots with Aerogard before going out I suppose.
When conditions are right (moist), these relatives of the worm come out and hang about in grass, on bushes and in trees waiting for their victims. They do this by ‘standing’ in an upright position by means of their posterior sucker.

Chemical sensors and vibration are used to detect an approaching host, usually mammals or humans. As the unsuspecting victim moves past they attach themselves with their anterior sucker. Once on, they make their way to a suitable vein near the skin surface, often around the ankle, upper foot or calf.
The Australian land leech (Gnatbobdellida libbata) has two jaws and makes a V-shaped incision which distinguishes it from other leeches in the world which have three jaws leaving a Y shaped incision.

Blood is prevented from clotting via an anticoagulant and a histamine with improves blood flow directly into the leech. Once the attached leech is fill-up with blood, perhaps tripling its size, they drop off the victim and find a suitable place to digest their meal.
This one didn't get a chance to enjoy its lunch, however.
Pass the Itch-X!

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