Oak dominated forests are characterized by periodic or episodic production of large acorn crops, punctuated by several consecutive years of poor acorn production. This phenomenon is called masting. Because acorns constitute a high quality food for many vertebrate consumers, masting behavior results in a flush of resources available to wildlife every 2-5 years.
Autumn is also the peak activity period for the adult stage of the black-legged tick.
Because deer are the preferred host for adult ticks, oak forests are the sites where these ticks take their terminal blood meal, drop off the deer, and lay eggs, which hatch the following summer. We have found, via both monitoring natural variation in acorn production, and by experimentally adding acorns to large forest plots, that the density of larval ticks hatching from eggs in summer is highly predictable on the basis of acorn availability the prior autumn. Therefore, the white-footed mouse is considered the principal natural reservoir for Lyme disease. Results of our monitoring and experimental studies demonstrate that population density of mice in summer is highly predictable on the basis of acorn production the prior autumn. The Ostfeld lab is currently testing whether this results in higher density of infected nymphal ticks two summers following heavy acorn production.