Balance of nature: Oaks and acorns and Lyme disease (Introduction)

by David Turell , Saturday, November 02, 2019, 18:00 (1847 days ago) @ David Turell

Note how moths, mice and acorns all interact to further the spread of Lyme disease:

https://science.sciencemag.org/content/279/5353/1023.full

Chain Reactions Linking Acorns to Gypsy Moth Outbreaks and Lyme Disease Risk

"Abstract
In eastern U.S. oak forests, defoliation by gypsy moths and the risk of Lyme disease are determined by interactions among acorns, white-footed mice, moths, deer, and ticks. Experimental removal of mice, which eat moth pupae, demonstrated that moth outbreaks are caused by reductions in mouse density that occur when there are no acorns. Experimental acorn addition increased mouse density. Acorn addition also increased densities of black-legged ticks, evidently by attracting deer, which are key tick hosts. Mice are primarily responsible for infecting ticks with the Lyme disease agent. The results have important implications for predicting and managing forest health and human health."

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"Lyme disease in the northeastern and north central United States is transmitted to humans by black-legged ticks infected with B. burgdorferi. Adult ticks feed and mate on white-tailed deer before dropping to the ground in autumn, laying eggs the following spring or early summer. Larvae hatch in midsummer and are free from infection with B. burgdorferi because of extremely low rates of transovarial transmission. White-footed mice are primarily responsible for infecting ticks with B. burgdorferi during the larval blood meal. Larvae then molt to nymphs that overwinter on the forest floor. In spring or early summer 1 year after egg hatch, infected nymphs seek vertebrate hosts, including humans, and may transmit B. burgdorferi to the host at this blood meal. The abundance of infected nymphs is the primary determinant of Lyme disease risk. Nymphs molt into adults that seek a deer host in the autumn. The location of deer in autumn determines the location of egg-laying adults and thus where host-seeking larvae should occur the following summer."

Comment: Lyme disease is a severe infection in humans in this country. It is an amazing example of how the parts of econiches are so tightly interrelated. I have actually had an adult deer tick on my leg several years ago. Luckily not a larval tick. We live in an oak forest with lots of deer.