Black-legged Ticks

From U.S. Geological Survey (USGS):

Is it the heat or the humidity? For black-legged ticks that carry Lyme disease, in the South it's both. They cope with the Southern climate in a way that explains why nearly all cases of Lyme disease come from 14 Northern, Midwestern and Mid-Atlantic states.

Heat in the 90s and humidity below super-soggy levels kill young black-legged ticks in days, a USGS-led study found. That's why Northern ticks perch on plant stems while Southern ticks hide under a layer of leaves, said study author Howard Ginsberg.

“In the North, when you walk through the woods you’re walking right through tick habitat,” Ginsberg said. “In the South, you’re walking on top of the habitat. We think that is a crucial difference." If the Mid-Atlantic states get warmer and dryer, scientists think Lyme disease rates there will go down.

Photo: Black-legged ticks in leaf litter in Tennessee, courtesy of Graham Hickling 




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