"The lone-star tick, the most commonly encountered tick in the St. Louis area, is very aggressive and will actually go after its host. It will run toward the host, faster than most people probably think a tick can run. It has its front legs out, and it's trying to find you. It has sensory organs on its front two legs, so it'll stand there and wave those legs around trying to detect your heat and your carbon dioxide signature. And when it gets closer, it kind of zig zags as it's approaching you, because it's homing in on your signal and when it gets really close, it grabs on.
"Sometimes I'll just stand there and watch the ticks do this," he says grinning. "It's pretty amusing.
"My record trap, the one that blew the rest out of the water, had 5,000 nymph lifestage lone-star ticks on it. We've done capture studies that suggest the nymphs don't travel much more than three meters, so that means there were 5,000 nymphal ticks within about a three-meter radius of where we put that trap down.
"It was remarkable. It took 10 man-hours to count all the ticks on that trap. We need to bring them into the lab to test them, so we pick them off with a pair of forceps one at a time and put them in ethanol."
Getting blood from a tick
The ticks are brought into the lab where they are pulverized and the mash is run through a DNA assay developed by Robert E. Thach, PhD, professor of biology in Arts & Sciences and of biochemistry and molecular biophysics in the School of Medicine, and Lisa S. Goessling, staff research associate in the Department of Biology.
"The technology for identifying mosquito blood meals has existed for some time," Allan explains, "because mosquitoes
|Contact: Diana Lutz|
Washington University in St. Louis