Lizard loss

If lizards are so important in keeping California relatively Lyme disease free then what would happen if we were to lose the lizards from an area? This is the sort of thing that might happen with a dramatic change in habitat.

Well this has been tested experimentally and the results are a little surprising.

“Our expectation going into this study was that removing the lizards would increase the risk of Lyme disease, so we were surprised by these findings,” said study lead author Andrea Swei, who conducted the study while she was a Ph.D. student in integrative biology at UC Berkeley. “Our experiment found that the net result of lizard removal was a decrease in the density of infected ticks, and therefore decreased Lyme disease risk to humans.”
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The researchers found that in plots where the lizards had been removed, ticks turned to the female woodrat as their next favorite host. On average, each female woodrat got an extra five ticks for company when the lizards disappeared.

However, the researchers found that 95 percent of the ticks that no longer had lizard blood to feast on failed to latch on to another host.

“One of the goals of our study is to tease apart the role these lizards play in Lyme disease ecology,” said Swei, who is now a post-doctoral associate at the Cary Institute of Ecosystem Studies in New York. “It was assumed that these lizards played an important role in reducing Lyme disease risk. Our study shows that it’s more complicated than that.”

Notwithstanding the results in this new study, Lane pointed out that the Western fence lizard are key to keeping infection rates down among adult ticks. “This study focused only on the risk from juvenile ticks, specifically those in the nymphal stage,” he said. “The earlier finding that adult ticks have lower infection rates because they feed predominantly on the Western fence lizard at the nymphal stage still holds.”

For more information check out this press release from UC Berkeley: Tick population plummets in absence of lizard hosts or the original article here: Impact of the experimental removal of lizards on Lyme disease risk.