LTREB: Pulsed Resources and the Dynamics of Rodents, Ticks, and Lyme-disease Risk in Oak Forests

Cary Institute Of Ecosystem Studies, Inc., Millbrook NY

Investigators

Abstract

0075277 Ostfeld Seven years of observational and experimental studies in oak forests suggest that risk of human exposure to Lyme-disease bearing ticks may be predictable almost two years in advance based on acorn production. High abundance of acorns in the fall stimulates population growth of white-footed mice, resulting in high mouse density the following spring and summer. Newly hatched larval ticks acquire the Lyme disease bacterium more efficiently from mice than from other hosts. Therefore, the greater the abundance of mice in summer, when larval ticks are active, the greater the opportunities to feed on mice. Larval ticks feeding from abundant mice the summer following a mast year molt into nymphs one year later, resulting in high density of infected nymphs, and therefore high risk of exposure to Lyme disease, two summers following mast production. The project will support continued core monitoring of acorn production, population dynamics of rodents, and density and infection prevalence of tick vectors, for the next five years. Five additional years of data will allow investigators to test the hypothesis that (1) significant relationships between acorn production, the summer density of mice, and the density of infected nymphal ticks occur across multiple masting cycles, (2) relationships between acorn production and tick density and infection prevalence, and between mouse density and tick density and infection prevalence, are best described by linear rather than curvilinear regressions, (3) significant relationships between acorn production and tick density and infection prevalence, and between mouse density and tick density and infection prevalence, are caused by the leverage from extremely high acorn production, and (4) interannual variation in mouse density, tick density and infection prevalence not explained by acorn production will be explained by interannual variation in climate. The core monitoring facilitates related research on impacts of pulsed resources on consumer community dynamics, (2) patterns and implications of dispersal by mice in heterogeneous landscapes and 93) the role of vertebrate diversity in Lyme disease dynamics. Continued long-term research will promote linkages between community ecology and epidemiology.