Arthropods in the news: Ticks

As you probably all ready know...Lyme disease is a serious bacterial disease transmitted by deer ticks (also known as black legged ticks): Ixodes scapularis, Pictured below:

Photo credit: Jae Nanthranoha (Bugguide.net)

Ticks are probably my least favorite arthropod, they can sit on a blade of grass for months just waiting for a mammal to walk past, on which they attach and take a blood meal, they are sneaky, and spread multiple diseases. Recently the incidences of Lyme disease have been increasing and scientists have been testing hypotheses hoping to find the mechanism for the spread. It was first hypothesized that the increase in deer populations was causing cases of Lyme disease, but that idea was refuted when it was discovered that the increases were not correlated with eachother. However, as reported in the link posted below, the researchers found that there was a correlation between increasing Lyme disease cases and the decline of the red fox.

MSNBC: Missing foxes fuel spread of Lyme disease

Looking at data from five states, it was discovered that the spread of Lyme disease correlated with the loss of red foxes, while deer populations were remaining steady. The scientists propose that the reason for this may be the increase in Coyote populations which prey on the foxes. The lack of foxes increases the amount of small mammals such as mice which also act of vectors for Lyme disease.

So...more coyotes --> less foxes --> more small mammals --> more Lyme disease. Got it?

Few people would have been able to predict that an increase in Coyote populations would lead to a spread of Lyme disease. However it is well known that alterations in populations of organisms can have unexpected consequences on food webs and within the ecosystem.