Local abundance of Ixodes scapularis in forests: effects of environmental moisture, vegetation characteristics, and host abundance

Publication date: Available online 14 September 2019Source: Ticks and Tick-borne DiseasesAuthor(s): Howard S. Ginsberg, Eric L. Rulison, Jasmine L. Miller, Genevieve Pang, Isis M. Arsnoe, Graham J. Hickling, Nicholas H. Ogden, Roger A. LeBrun, Jean I. TsaoAbstractIxodes scapularis is the primary vector of Lyme disease spirochetes in eastern and central North America, and local densities of this tick can affect human disease risk. We sampled larvae and nymphs from sites in Massachusetts and Wisconsin, USA, using flag/drag devices and by collecting ticks from hosts, and measured environmental variables to evaluate the environmental factors that affect local distribution and abundance of I. scapularis. Our sites were all forested areas with known I. scapularis populations. Environmental variables included those associated with weather (e.g., temperature and relative humidity), vegetation characteristics (at canopy, shrub, and ground levels), and host abundance (small and medium-sized mammals and reptiles). The numbers of larvae on animals at a given site and season showed a logarithmic relationship to the numbers in flag/drag samples, suggesting limitation in the numbers on host animals. The numbers of nymphs on animals showed no relationship to the numbers in flag/drag samples. These results suggest that only a small proportion of larvae and nymphs found hosts because in neither stage did the numbers of host-seeking ticks decline with increased numbers on hosts. Canopy cover wa...
Source: Ticks and Tick borne Diseases - Category: Zoology Source Type: research